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ACI 355.4M-11 Qualification of Post-Installed Adhesive Anchors in Concrete (ACI 355.4M-11) An ACI Standard and Commentary Reported by ACI Committee 355

First Printing September 2011 American Concrete Institute® Advancing concrete knowledge Qualification of Post-Installed Adhesive Anchors in Concrete (ACI 355.4M-11) and Commentary Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of ACI. The technical committees responsible for ACI committee reports and standards strive to avoid ambiguities, omissions, and errors in these documents. In spite of these efforts, the users of ACI documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incorrect. Users who have suggestions for the improvement of ACI documents are requested to contact ACI via the errata website at www.concrete.org/committees/errata.asp. Proper use of this document includes periodically checking for errata for the most up-to-date revisions. ACI committee documents are intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. Individuals who use this publication in any way assume all risk and accept total responsibility for the application and use of this information. All information in this publication is provided “as is” without warranty of any kind, either express or implied, including but not limited to, the implied warranties of merchantability, fitness for a particular purpose or non-infringement. ACI and its members disclaim liability for damages of any kind, including any special, indirect, incidental, or conse- quential damages, including without limitation, lost revenues or lost profits, which may result from the use of this publication. It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involved with its use. ACI does not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. Participation by governmental representatives in the work of the American Concrete Institute and in the development of Institute standards does not constitute governmental endorsement of ACI or the standards that it develops. Order information: ACI documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI. Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP). American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 U.S.A. Phone: 248-848-3700 Fax: 248-848-3701 www.concrete.org ISBN 978-0-87031-409-4

A U.S. Customary version of this document ACI 355.4M-11 (ACI 355.4-11) is available at www.concrete.org Qualification of Post-Installed Adhesive Anchors in Concrete (ACI 355.4M-11) and Commentary An ACI Standard Reported by ACI Committee 355 Donald F. Meinheit J. Bret Turley Chair Secretary Tarek S. Aziz Werner A. F. Fuchs Richard E. Klingner Jake Olsen Ranjit L. Bandyopadhyay* Branko Galunic Anthony J. Lamanna Alan D. Price Peter J. Carrato Brian C. Gerber Harry B. Lancelot III John F. Silva Harry A. Chambers Michael Gong Patrick J. E. Sullivan Herman L. Graves III Nam-Ho Lee Harry Wiewel Ronald A. Cook Christopher Heinz Lee W. Mattis Richard E. Wollmershauser Rolf Eligehausen Bruce I. Ireland Robert R. McGlohn Sam S. Eskildsen *Deceased. The committee would like the recognize Christopher LaVine for his significant contributions to this document. Consulting members Edwin G. Burdette Paul R. Hollenbach Robert W. Cannon Conrad Paulson Neil M. Hawkins Dan R. Stoppenhagen This standard prescribes testing programs and evaluation requirements for Keywords: adhesive anchors; cracked concrete; fasteners; post-installed post-installed adhesive anchors intended for use in concrete under the anchors; qualification procedures; uncracked concrete. design provisions of ACI 318M. Testing and assessment criteria are provided for various conditions of use, including seismic loading; CONTENTS sustained loading; aggressive environments; reduced and elevated temper- Chapter 1—Introduction and scope, p. 3 atures; and for determining whether anchors are acceptable for use in uncracked concrete only, or acceptable for service both in cracked and 1.1—Introduction uncracked concrete. Criteria are provided for establishing the characteristic 1.2—Scope bond strength, reductions for adverse conditions, and the anchor category 1.3—Units of measurement and associated job-site quality control requirements. Chapter 2—Notation and definitions, p. 5 The official version of this ACI document uses inch-pound units. A 2.1—Notation conversion of an ACI document into SI units is for the convenience of 2.2—Defintions users. Care has been taken to ensure that the conversion is correct; however, ACI does not guarantee its accuracy. Official interpretation of Chapter 3—General requirements, p. 11 this ACI document shall be based only on the U.S. customary units. 3.1—Test organization 3.2—Variables and options ACI Committee Reports, Guides, and Commentaries are 3.3—Test requirements intended for guidance in planning, designing, executing, and 3.4—Assessment for multiple anchor element types for inspecting construction. This document is intended for the use adhesive anchors of individuals who are competent to evaluate the significance 3.5—Assessment for alternate drilling methods and limitations of its content and recommendations and who will accept responsibility for the application of the material it ACI 355.4M-11 supersedes ACI 355.4-10 (provisional), was adopted July 5, 2011, and contains. The American Concrete Institute disclaims any and all published September 2011. responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom. Copyright © 2011, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any Reference to this document shall not be made in contract means, including the making of copies by any photo process, or by electronic or documents. If items found in this document are desired by the mechanical device, printed, written, or oral, or recording for sound or visual reproduction Architect/Engineer to be a part of the contract documents, they or for use in any knowledge or retrieval system or device, unless permission in writing shall be restated in mandatory language for incorporation by is obtained from the copyright proprietors. the Architect/Engineer. 1

2 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Chapter 4—Requirements for test specimens, 8.11—Tests to determine shear capacity of anchor elements anchor installation, and testing, p. 17 with nonuniform cross section 4.1—Testing by ITEA and manufacturer 8.12—Simulated seismic tension tests 4.2—Test samples 8.13—Simulated seismic shear tests 4.3—Concrete for test members 4.4—Requirements for test members Chapter 9—Supplemental tests, p. 38 4.5—Anchor installation 9.1—Round-robin tests 4.6—Drill bit requirements 9.2—Tests to determine minimum member thickness 4.7—Test methods 4.8—Tests in cracked concrete Chapter 10—Assessment of anchors, p. 39 4.9—Changes to products 10.1—Analysis of data 10.2—Normalization of anchor capacities for measured Chapter 5—Requirements for anchor identification, concrete bond and steel strengths p. 24 10.3—Establishing characteristic values 10.4—Assessment of characteristic tension capacity 5.1—Basic requirements associated with concrete breakout and pullout 5.2—Verification 10.5—Assessment of steel tension capacity 5.3—Fingerprinting adhesive materials 10.6—Assessment of steel shear capacity 5.4—Packaging 10.7—Assessment of minimum member thickness 10.8—Assessment of maximum tightening torque Chapter 6—Reference tests, p. 24 10.9—Assessment of behavior under crack cycling 6.1—Purpose 10.10—Assessment of freezing-and-thawing behavior 6.2—Required tests 10.11—Assessment of sustained load behavior 6.3—Conduct of tests 10.12—Assessment of performance associated with installation direction Chapter 7—Reliability tests, p. 25 10.13—Assessment of performance at elevated temperature 7.1—Purpose 10.14—Assessment of performance with decreased 7.2—Required tests installation temperature 7.3—Conduct of tests 10.15—Assessment for cure time at standard temperature 7.4—Reliability tests 10.16—Assessment of durability requirement 7.5—Sensitivity to hole cleaning—dry concrete 10.17—Assessment of performance in corner test 7.6—Sensitivity to hole cleaning—saturated concrete 10.18—Assessment of performance in minimum spacing 7.7—Sensitivity to hole cleaning—water-filled hole and edge distance test 7.8—Sensitivity to hole cleaning—submerged concrete 10.19—Assessment of performance under seismic tension 7.9—Sensitivity to mixing effort 10.20—Assessment of performance under seismic shear 7.10—Sensitivity to installation in water-saturated concrete 10.21—Establishment of hole cleaning procedures 7.11—Sensitivity to installation in water-filled hole— 10.22—Establishment of on-site quality control and saturated concrete installation conditions 7.12—Sensitivity to installation in submerged concrete 10.23—Assessment based on installation and environmental 7.13—Sensitivity to crack width—low-strength concrete conditions 7.14—Sensitivity to crack width—high-strength concrete 10.24—Assessment for fire exposure 7.15—Sensitivity to crack width cycling 7.16—Sensitivity to freezing and thawing Chapter 11—Data presentation, p. 51 7.17—Sensitivity to sustained loading at standard and 11.1—General requirements maximum long-term temperature 11.2—Contents of evaluation report 7.18—Sensitivity to installation direction 11.3—Data presentation 7.19—Torque test Chapter 12—Independent testing and evaluation Chapter 8—Service-condition tests, p. 32 agency requirements, p. 53 8.1—Purpose 8.2—Required tests 12.1—General requirements 8.3—Conduct of tests 12.2—Certification 8.4—Tension tests in uncracked and cracked concrete 8.5—Tension tests at elevated temperature Chapter 13—Quality control requirements, p. 54 8.6—Tension tests with decreased installation temperature 13.1—Quality assurance program 8.7—Establishment of cure time at standard temperature 13.2—Quality control manuals 8.8—Durability assessment 13.3—Special inspection 8.9—Verification of full concrete capacity in a corner 8.10—Determination of minimum spacing and edge Chapter 14—References, p. 54 distance to preclude splitting 14.1—Referenced standards and reports 14.2—Cited references

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 3 CHAPTER 1—INTRODUCTION Table 1.1—Overview of anchor systems 1.1—Introduction Anchor Embedded part Assessment criteria This standard prescribes testing and evaluation requirements type for post-installed adhesive anchor systems intended for use in concrete under the provisions of ACI 318M. Criteria are Threaded rods, deformed Uncracked Table 3.1 separately prescribed to determine the suitability of adhesive Adhesive reinforcing bars, or inter- concrete anchors used in uncracked concrete only, or in both cracked Table 3.2 or and uncracked concrete. Criteria are prescribed to determine anchor nally threaded steel sleeves Cracked and Table 3.3 the design parameters and performance category for adhesive with external deformations uncracked anchors. Included are assessments of the adhesive anchor concrete system for bond strength, reliability, service conditions, and quality control. Special inspection (13.3) is required during diameter to anchor element diameter provides a demarcation anchor installation as noted in 10.22. Table 1.1 provides an between conditions where a single bond strength can be used overview of the scope. to evaluate anchor strength and conditions where bond strengths at both the anchor interface and concrete interface R1.1 This standard prescribes the testing programs must be determined to evaluate anchor strength. In addition, required to qualify post-installed adhesive anchor systems the value of 1.5da is based on consideration of typical practice for design in accordance with ACI 318M, Appendix D. whereby most organic adhesives are used with thin bond Appendix D requires that anchors be tested either for use lines to limit both adhesive shrinkage and creep of the exclusively in uncracked concrete or for use in cracked and anchor when under load. The design method deemed to uncracked concrete conditions, whereby it is understood that satisfy the anchor design requirements of ACI 318M, the presence of cracking may occur at any time over the Appendix D, is based on an analysis of an anchor database service life of the anchors. Test and assessment criteria are with a maximum diameter of 50.8 mm. While ACI 355.4M provided for various conditions, including loads (seismic gives no limitations on maximum anchor diameter, for and sustained), environmental with regard to humidity and anchors beyond this dimension, the testing authority should temperature, and determination if anchors are acceptable decide if the tests described in this standard are appli- for use in cracked or uncracked concrete. Refer to Cook and cable or if alternative tests and analyses are more appro- Konz (2001) for a review of factors that influence adhesive priate. It may also be desirable to reconsider those tests anchor behavior. Refer to Fuchs et al. (1995) for background where only small, medium, and large diameters are tested on the concrete breakout design model and to Eligehausen et when the upper diameter is much larger than 38 mm. al. (2006) and Zamora et al. (2003) for a discussion of bond models for adhesive and grouted anchors. For a discussion A limitation on the minimum embedment length of adhesive of issues associated with the qualification and design of anchors is necessary to ensure conformance with the design systems for post-installed reinforcing bars, refer to Spieth et method deemed to satisfy the anchor design requirements of al. (2001). ACI 318M, Appendix D. 1.2—Scope 1.2.2 The minimum member thickness shall not be less This standard applies only to post-installed adhesive than the value given by Eq. (10-21). Values of Δh in Eq. (10-21) shall be permitted if they are verified by tests according to anchors as defined herein. Table 3.1, Test no. 14, and Table 3.2, Test no. 20, or Table 3.3, Test no. 15. R1.2 Adhesive anchors resist tension loads with a combi- nation of adhesion and mechanical bond (micro-interlock). 1.2.3 This standard does not address the following systems Different anchor designs and adhesive types may exhibit a and use conditions: range of performance characteristics. In particular, the sensitivity of adhesive anchors to variations in installation 1. Bulk adhesives mixed in open containers without auto- and service-condition parameters (such as hole cleaning, matically controlled metering and mixing of adhesive installation orientation, and cracked concrete characteristics) components. may vary widely from each system. ACI 318M addresses this situation by matching capacity reduction factors to anchor 2. Adhesives to adhere structural elements to concrete performance categories that are, in turn, established surfaces outside of a drilled hole. through a series of reliability tests. 3. Adhesive anchors in aggressive environments not 1.2.1 This standard applies to anchors with a diameter da specifically considered in this standard. of 6 mm or larger. The drilled hole shall be approximately cylindrical with a diameter do ≤ 1.5da. This standard also 4. Adhesive anchors to resist fatigue or shock loading. applies to anchors with an anchor embedment depth hef not R1.2.3 Correct proportioning (metering) and mixing of less than four diameters (4da), or 41 mm, and an embedment adhesive components is critical to their performance. Bulk depth not exceeding 20da. mixing and delivery of adhesives (for example, those with paddle mixers in buckets), while appropriate for some appli- R1.2.1 The minimum diameter of 6 mm is based on cations, may not provide anchor performance consistent practical considerations regarding the limit of structural with the assumptions of this standard. These systems are not anchor applications. The upper limit on the ratio of hole considered to provide controlled metering of adhesive components. Bulk dispensing equipment that provides automatic metering and mixing of the adhesive components is included; however, ongoing monitoring is required to check that the equipment is operating within tolerances in accordance with the Manufacturer’s Printed Installation

4 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Fig. R1.1—Examples of post-installed reinforcing bars proportioned with anchor theory and with concepts of reinforcement development and splicing. Instructions (MPII), particularly with respect to mixture adhesive anchors exclusively for short-term loads is not ratios, leak tightness, and dwell time. permitted by this standard. This standard is not appropriate for assessing the use of R1.2.4 While it is permissible to use adhesive anchors to adhesives to adhere structural elements to the concrete surface. resist short-term loads such as those from wind or earthquake, Examples include bonded steel plates or external carbon fiber the sustained load tests and corresponding assessment reinforcement. Other standards exist for these purposes. This described herein are not optional. All anchors qualified in standard includes tests to assess the sensitivity of adhesive accordance with ACI 355.4M are suitable for sustained anchor systems to a limited range of aggressive environments, loads within the use parameters established in the assess- including moisture, highly alkaline fluids, and sulfur dioxide. ment (7.17 and 10.4.7). While it is believed that these exposure environments envelop a range of possible exposures, specific environments (for 1.2.5 Adhesive anchor systems shall exhibit characteristic example, radiation exposure and chemical production bond strengths as determined in accordance with Eq. (10-12) environments) may require unique assessment. equal to or exceeding the minimum permissible bond strength τk,min. Adhesive anchor systems that do not exhibit Due to the variety of possible loading conditions associated characteristic bond strengths equal to or exceeding the with fatigue and shock loading, this standard does not minimum permissible bond strength in accordance with include tests for these loading variants. Fatigue and shock 10.2, shall not be qualified according to this standard. loading may result in reductions in bond strength, steel strength, and concrete strength, and these effects are not R1.2.5 ACI 318M, Appendix D, provides default bond addressed by this standard. Caution should be exercised in stress values for specific constellations of use parameters the determination of whether cyclic loading should be that may be used in place of values from an evaluation report explicitly considered. These conditions may be evaluated in accordance with this standard. Because the default values separately for specific systems using generally accepted are independent of the adhesive anchor system selected, they principles. Fatigue is generally less of a problem for the represent minimum values for the assessment of any adhesive adhesive than for the anchor element; provisions of preload anchor system under this standard. The minimum values and in the anchor to reduce the level of stress fluctuation in the corresponding use parameters are given in Table 10.2. anchor element is only effective if sufficient unbonded length is provided to ensure a reasonable degree of elastic stretch. 1.2.6 In general, ACI 355.4M is intended to address the assessment of adhesive anchors for cases where anchor 1.2.4 Adhesive anchors shall be evaluated for sustained design theory applies. It is not intended to address the loading with the provisions of this standard. Qualification of assessment or design of post-installed reinforcing bars proportioned according to the concepts of development and splicing of reinforcement.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 5 R1.2.6 This standard is intended to provide parameters for do = nominal diameter of drilled hole in the the design of adhesive anchors in conjunction with the concrete, mm, see 2.1 provisions of ACI 318M, Appendix D. Those provisions are derived from the principles of anchor theory, whereby Fi = test result normalized to considered concrete anchor forces are transferred to the concrete in a manner strength i, N that generally precludes splitting of the concrete and where spacing, edge distance, and member thickness are explicitly Fk = characteristic capacity for a test series, considered in the evaluation of the concrete breakout capacity calculated according to 10.3, N (Fig. R1.1(a)). It is not intended to address the assessment or design of post-installed reinforcing bars proportioned Ftest,i = mean anchor capacity as determined from test according to the concepts of development and splicing of series i, N reinforcement (Fig. R1.1(b)). While the provisions of Chapter 12 of ACI 318M may be used to establish embed- Ftest,i,fc = mean capacity for test series i, normalized to ment lengths for post-installed reinforcing bars in such concrete strength fc, in accordance with 10.2, N cases, the ability of an adhesive anchor system to transfer loads to adjacent embedded bars, particularly where longer Fy = tension force corresponding to bolt yield in splice lengths are required, should be verified by appro- accordance with Eq. (10-22), N priate testing. Testing for the splice length is outside the scope of this standard. fc′ = specified strength of concrete, MPa fc,i = mean concrete compressive strength measured with standard cylinders for concrete of batch i, MPa fc,test,x = mean concrete compressive strength measured with standard cylinders of the test members used for test series x, MPa 1.3—Units of measurement ft = mean ultimate tensile strength of anchor steel Values in this specification are stated in SI units. A as determined by test, MPa companion specification in inch-pound units is also available. futa = specified tensile strength of anchor steel, MPa fut,test = specified ultimate tensile strength of steel anchor elements used in seismic tests, MPa CHAPTER 2—NOTATION AND DEFINITIONS fya = specified yield strength of anchor steel, MPa h = thickness of test member in which an anchor 2.1— Notation is installed, measured perpendicular to the Ase,N = effective cross-sectional area of anchor in tension, mm2 concrete surface, mm, see Fig. 2.1 Ase,V = effective cross-sectional area of anchor in hef = effective embedment depth, measured from shear, mm2 the concrete surface to the deepest point at cac = critical edge distance required to develop the which bond to the concrete is established, basic concrete breakout strength of anchor in mm, see Fig. 2.1 uncracked concrete without supplementary hmin = minimum member thickness specified by the reinforcement to control splitting, mm anchor manufacturer and verified in accordance cmin = minimum anchor edge distance required to with 9.2 and 10.7, mm prevent splitting during anchor installation, hsl = slice thickness as measured immediately prior mm, see 8.10 to punch testing in accordance with 8.8, mm K = tolerance factor corresponding to a 5 percent da = nominal outside diameter of post-installed probability of nonexceedence with a confidence anchor, mm, see Fig. 2.1 of 90 percent, derived from a noncentral t- de = nominal diameter of bolt or threaded anchor distribution for which the population standard element in a sleeved insert, mm, see Fig. 2.1 deviation is unknown Fig. 2.1—Adhesive anchor dimensional parameters.

6 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY k = effectiveness factor, whose value depends on Nk,p,nom,uncr= characteristic tension capacity corresponding = the type of anchor to service-condition tests in low- and high- kcr = effectiveness factor for anchors tested in kf = cracked concrete strength uncracked concrete, N km = friction factor of threads kuncr = mean coefficient for the concrete breakout Nk,r,i = characteristic tension capacity of an anchor in tension reliability test series i, N lside effectiveness factor for anchors tested in uncracked concrete Nk,st = characteristic tension capacity at short-term dimension of the side of a cube or diameter of a elevated temperature, N cylinder for conducting a freezing-and- thawing test, mm Nlt = mean tension capacity of an anchor at long- 95 percent fractile at 90 percent confidence of term elevated temperature, N the induced tension force corresponding to 1.3Tinst, N Nm = minimum tension load to be applied in the 95 percent fractile at 90 percent confidence of simulated seismic tension test, N the force corresponding to loss of adhesion N95% = between the anchor element and the adhesive Nm,reduced = reduced minimum tension load at which the for anchor diameter d, N anchor successfully completes the simulated minimum value of tension load corresponding to loss of adhesion in test series i, N seismic tension test, N, see 10.19.1.2 tension load corresponding to loss of adhesion N95%,slip,d = between the adhesive and the concrete, N No = mean tension capacity of an anchor, N tension load corresponding to loss of adhesion in reliability test series i, test j, N No,i = mean tension capacity of an anchor in reference test series i, N minNadh,i = No,i,confined= mean tension capacity of anchor in confined reference tests i, N Nadh = Norigin = tension load corresponding to origin of load- displacement curve, N Nadh,i,j = Np = characteristic tension pullout capacity of an anchor, 5 percent fractile of test results, as determined in accordance with 10.3, N Ncure = Nr,i = mean tension capacity of an anchor in reliability test series i, N Ncure+24h = mean tension capacity corresponding to the Ns = characteristic tension steel capacity of an anchor manufacturer’s published minimum cure as determined in accordance with 10.3, N time plus 24 hours, N Nst = mean tension capacity at short-term elevated temperature, N Neq = maximum tension load to be applied in the simulated seismic tension test, N Nsust,ft = sustained tension load applied during freezing-and-thawing cycles, N Neq,reduced= reduced maximum tension load at which the anchor successfully completes the simulated Nsust,lt = sustained tension load applied at long-term test temperature, N seismic tension test, N, see 10.19.1.2 Nu = peak tension load measured in a tension test, N Ni = intermediate tension load to be applied in the simulated seismic tension test, N Nu,i = peak tension load measured in a tension test in test series i or concrete batch i, N Ni,reduced = reduced intermediate tension load at which the anchor successfully completes the simulated Nu,i = mean ultimate tension load measured in a tension test in test series i or concrete batch i, N seismic tension test, N, see 10.19.1.2 Nk = characteristic tension capacity of an Nu,i,fc = peak tension load measured in a tension test anchor, 5 percent fractile of test results, as conducted in test series i or concrete batch i, determined in accordance with 10.3, N normalized to concrete strength fc, N Nk,cure = characteristic tension capacity corresponding Nu,i,j = peak tension load measured in a tension test to the manufacturer’s published minimum in test series or concrete batch i, test j, N cure time, N Nw = tension load applied to anchor during crack width cycling, N Nk,cure+24h = characteristic tension capacity corresponding to the manufacturer’s published minimum n = number of replicates in a test series, number of cure time plus 24 hours, N anchors in an anchor group, and exponent for Nk,i = characteristic tension capacity of an anchor in determining relationship of bond stress as a test member i or concrete batch i, N function of concrete compressive strength Nk,lt = characteristic tension capacity at long-term smin = minimum anchor spacing as required to elevated temperature, N prevent splitting during anchor installation or Nk,o,i = characteristic tension capacity of an anchor in tension loading, mm, see 8.10 reference test series i, N Tinst = specified tightening torque for setting or Nk,p,nom,cr = characteristic tension capacity corresponding prestressing of an anchor, according to the to service-condition tests in low- and high- MPII, N-m strength cracked concrete, N tservice = intended anchor service life, in hours

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 7 Veq = maximum shear load to be applied in the β = reduction factor evaluated as the minimum of Veq,reduced = simulated seismic shear test, N reduced maximum shear load at which the α/αreq and αadh for reliability tests and anchor successfully completes the simulated service-condition tests listed in Tables 10.3 seismic shear test, N, see 10.20.1.2 intermediate shear load to be applied in the and 10.4 in accordance with Eq. (10-12) simulated seismic shear test, N reduced intermediate shear load at which the Δ = anchor displacement as measured in a test, mm anchor successfully completes the simulated Vi = seismic shear test, N, see 10.20.1.2 Δ0.3 = displacement at N = 0.3Nu, mm Vi,reduced = minimum shear load to be applied in the Δlim = mean displacement corresponding to loss of simulated seismic shear test, N reduced minimum shear load at which the Δorigin adhesion load Nadh, mm anchor successfully completes the simulated = displacement at origin of load displacement seismic shear test, N, see 10.20.1.2 mean shear capacity of an anchor in reference curve, mm test series i, N Vm = characteristic shear capacity corresponding Δservice = extrapolated estimate of the total displacement Vm,reduced = to steel failure, N over the anchor intended service life, mm seismic shear capacity as governed by steel failure, N Δservice = mean value of the extrapolated estimate of the ratio of reliability to reference tension test total displacement over the anchor intended results calculated in accordance with 10.4.3 reduction factor for alkalinity in accordance service life, mm with 10.16 Vo,i = ratio of the load at loss of adhesion to the peak Δt=0 = initial displacement under sustained load, mm Vs = load calculated in accordance with 10.4.4 Δh = concrete thickness beyond hef, mm, see 2.1 VS,seis = additional reduction factor for Anchor Δ(t) = displacement at time t under sustained load, mm α = Category 3 in accordance with 10.4.6.2 adjustment factor for regional variations in Δw = required change in crack width, in addition to concrete in accordance with 10.4.1.2 reduction factor for larger coefficients of the initial hairline crack width as measured variation in accordance with 10.4.2 reduction factor for durability tests in after anchor installation, mm accordance with 10.16 reduction factor for maximum long-term φ = strength reduction factor for concrete failure temperature in accordance with 10.13.1 reduction factor for seismic tension loading and steel failure modes corresponding to the in accordance with 10.19 αalk = threshold value of α given in Table 3.1, 3.2, anchor category established in accordance or 3.3 αreqfor Anchor Category 3 for corresponding with 10.4.6 and 10.5, respectively reliability test in accordance with Table 10.5 αadh = or 10.6 νtest,x = sample coefficient of variation for test series reduction factor for service-condition tests x equal to the sample standard deviation performed as confined tests in accordance αcat3 = with 10.4.5.1 divided by the mean, percent reduction factor for maximum short-term temperature in accordance with 10.13.2 τdur,i = minimum of mean bond stress corresponding reduction factor for sulfur in accordance with to durability tests with test member i or αconc = 10.16 reduction factor for seismic shear loading in concrete batch i stored in different media accordance with 10.20 αCOV = reduction factor for reliability tests in according to 8.8.3, MPa accordance with 10.4.7.1 αdur = reduction factor for sustained load reliability τi = calculated bond stress corresponding to peak test in accordance with 10.4.7.2 load in a tension test, MPa αlt = τi = mean bond stress corresponding to test series i or concrete batch i, MPa αN,seis = τk,(cr,uncr) = characteristic bond stress in cracked or uncracked concrete, respectively, adjusted for variations in concrete batches and reduced in αreq = accordance with 10.4.5.3.2, MPa αreq,cat3 = τk,i = characteristic bond stress corresponding to tension tests in test member i or concrete batch i, MPa τk,min = minimum permissible bond strength in accor- dance with 1.7, MPa αsetup = τk,o,i = characteristic bond stress corresponding to reference tension tests in test member i or concrete batch i, MPa αst = τk,seis,(cr,uncr)= seismic tension bond resistance calculated in αsulf = accordance with 10.4.5.5, MPa αV,seis = αρ = τo,i = bond stress corresponding to a reference αρ,sust = tension test in test member i or concrete batch i, MPa τref,fc = mean bond stress corresponding to round- robin tests, MPa τu = calculated bond stress adjusted for variations in concrete batches, MPa τu = mean bond stress, MPa

8 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY τu,i = mean bond stress from reliability test series in water-saturated concrete, water-filled holes, overhead concrete batch or test member i, MPa installation, and other adverse installation conditions. 2.2—Definitions aggressive environment—any anchor environmental adhesive—any adhesive comprised of chemical components exposure that may be characterized as equivalent to that produced by exposure of the adhesive compound to an alkaline that cure when blended together. Adhesives are formulated environment and a high sulfur dioxide concentration. from organic polymers, or a combination of organic polymers and inorganic materials. Organic polymers used in adhesives aggressive environment —testing of adhesive compounds can include, but are not limited to, epoxies, polyurethanes, as used in adhesive anchor applications to resist chemical polyesters, methyl methacrylates, and vinyl esters. exposure is limited in this standard to alkalinity, which is mandatory, and sulfur dioxide, which is optional. As both of adhesive—it is not intended that adhesives be restricted to these tests involve exposure to water, evaluation of the adhesive those listed in this standard and the listing of a specific for susceptibility to hydrolyzation is included as well. ACI adhesive does not imply any preference. The suitability of a Committee 355 believes alkalinity is the most common specific adhesive for anchoring applications may also be aggressive chemical exposure condition. This standard dictated by health and safety requirements as contained, for considers the effects of alkalinity and sulfur dioxide separately, example, in the product Material Safety Data Sheet (MSDS). and the αdur factor is taken as the condition representing the This standard does not address issues such as adhesive greatest reduction in strength. toxicity, safe disposal of adhesive compounds, or confor- mance with sustainable building requirements as applicable. anchor—a steel element post-installed into a hardened concrete member and used to transmit applied loads. Steel adhesive anchor—a post-installed anchor, inserted into elements for adhesive anchors may include threaded rods, hardened concrete with an anchor hole diameter not greater deformed reinforcing bars, or internally threaded steel than 1.5 times the anchor diameter, that transfers loads to the sleeves with external deformations. concrete by bond between the anchor and the adhesive and bond between the adhesive and the concrete. anchor—the term “anchor,” as used herein, refers to the steel component bonded to the concrete with adhesive. The adhesive anchor—evaluation of the tension resistance of bond model used in ACI 318M is appropriate for steels only grouted anchors installed in hole diameters greater than because the use of non-steel elements may influence the bond 1.5da requires separate consideration of bond stresses stress distribution and may involve failure modes not developed along the anchor element/grout interface, as well considered in the model. as between the grout and the concrete. Because these anchors may demonstrate tension behavior that does not anchor category—an assigned rating that corresponds to conform to the design method deemed to satisfy the anchor a specific strength reduction factor φ for concrete failure design requirements of ACI 318M, Appendix D, they are not modes associated with anchors in tension. The anchor considered in this standard. category is established by performance of the anchor in reliability tests. adhesive anchor system—for the purposes of this standard, the adhesive anchor system is comprised of the following anchor category—assignment of the anchor category is components: intended to represent sensitivity of the anchor system (for example, variations in installation conditions). It is used to • Anchor determine the strength reduction factor in ACI 318M, Appendix D. • Proprietary adhesive compounds in combination with a mixing and delivery system where different mixing and anchor installation—unless otherwise noted, the process delivery systems are provided for the same adhesive defined by the MPII for the subject anchor. anchor system, it shall be verified through testing that the mixing and delivery systems yield equivalent anchor installation—anchor installation parameters performance of the installed anchor shall include, but are not limited to, ambient air and concrete temperature at the time of installation, concrete • Accessories for cleaning the drilled hole, including type and strength, presence of moisture or water in the brushes, air nozzles, and other items needed to drilled hole at installation time, hole drilling method, hole complete the cleaning process diameter, hole cleaning and preparation requirements, adhesive material conditioning, mixing and placement, • Printed instructions for the adhesive anchor installation anchor element installation and retention, gel and cure time including hole preparation, injection, and cure for all restrictions, and installer safety requirements. It is assumed environmental conditions permitted in the qualification. that all aspects of anchor installation are described in the MPII for all installation conditions, including installation adhesive anchor system—this standard addresses the direction and concrete temperature. testing and assessment of adhesive anchor systems, whereby all components of the system (for example, the anchor itself bulk adhesives—two-component adhesives supplied in and all accessories and instructions necessary for the industrial quantities in either barrels or 4 to 19 L cans. They installation in the drilled hole) are included in the assessment. are delivered with a bulk dispensing machine whereby Instructions for use as provided by the manufacturer, should metering and mixing of the components are automatically include specific instructions for all conditions of installation controlled during dispensing through a metering manifold to be included in the evaluation, including installation in and disposable mixing nozzle.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 9 bulk adhesives—the use of bulk adhesive in conjunction associated with a closed crack may be influenced by the with automatic mixing and metering equipment that ensures presence of anchors installed in the crack path and by the the correct proportioning and mixing of the adhesive crack width cycling history of the test member. components is permitted in conjunction with the standard. Such equipment is considered part of the adhesive anchor concrete batch—a mixture of specific amounts of system. The use of bulk adhesive components metered, cement, aggregate, water, and admixtures prepared and mixed, and delivered manually (that is, poured) is not placed at a specific time and cured in a specific manner. addressed by this standard. concrete batch—a concrete batch is one mixture of capsule anchor systems—adhesives for anchor applications concrete from which test members are made. It represents a packaged in glass or foil capsules. Capsule diameter single mixture so that variations from different batches can corresponds approximately to nominal anchor diameter. The be eliminated in the testing. Batch control requirements are quantity of resin, hardener, and aggregate component in each provided in 4.4. capsule is suitable for a single anchor application. Component mixing is achieved during anchor installation. The capsule is concrete breakout failure—failure of the anchor in an fragmented and becomes part of the hardened resin matrix. unconfined tension test, characterized by the formation of a conical fracture surface originating at or near the embedded capsule anchor systems—unlike cartridge and bulk adhesive end of the anchor element and projecting to the surface of the anchor systems, capsule anchor systems are designed to concrete test member. deliver a finite quantity of adhesive into the drilled hole. Their use, therefore, is generally limited to discrete embedment concrete breakout failure—the concrete breakout surface depths for each anchor diameter corresponding to complete is associated with concrete breakout failure mode. The filling of the annular gap with cured adhesive. For deeper design method deemed to satisfy the anchor design require- embedments, use of multiple capsules may be specified by the ments of ACI 318M, Appendix D, idealizes the shape and manufacturer. The drilling action during setting of spin-set dimensions of the concrete breakout surface to establish capsule anchors is critical to the correct mixing and curing spacing and edge distance effects associated with concrete of adhesive. Unlike cartridge systems, the characteristics of breakout, edge breakout, and pryout failure modes. Adhesive the tool used for setting of the anchor, such as horsepower, anchors may exhibit concrete breakout failure before torque, and rpm, is an integral part of the anchor system. attainment of the maximum bond stress achievable for the Capsule anchors that are set with hammering action only, adhesive in question. Sometimes concrete breakout surface hammer-set may have other parameters that are critical in formation is observable in the test and in other cases it may this regard. not reach the concrete surface before the associated fracture process in the concrete precipitates a bond failure. Care cartridge systems—two-component adhesives for anchor should be taken in the characterization of failure modes applications packaged in cartridges for use with either manually- based on test observations. or power-driven dispensers. Metering and mixing of the components is automatically controlled as the adhesive is cracked concrete—for the purposes of this standard, a dispensed through a manifold and disposable mixing nozzle. test member with a uniform crack width over the depth of the concrete test member. cartridge systems—cartridge systems may employ different types of injection equipment depending on, for cracked concrete—for purposes of this test program, example, the anchor size and hole depth. Each injection cracked concrete refers to an idealized crack with parallel system used with the adhesive anchor system should be walls, and not the wedge-shaped crack opening expected in evaluated as part of the anchor qualification in accordance bending. Parallel crack openings are used because they with this standard. represent the most critical condition for the anchor response to loading. characteristic value—the 5 percent fractile, that is, value with a 95 percent probability of being exceeded with a cure time—the elapsed time from after mixing the adhesive confidence of 90 percent. Refer to five percent fractile. material components until the adhesive material in the drilled hole achieves mechanical properties that correspond characteristic value—the characteristic value is used for to those established with the test conducts described in this design in ACI 318M, Appendix D. The characteristic value is standard and are consistent with final design. less than the average by a percentage of the average and based on the number of tests conducted, the confidence level cure time—cure time is influenced by concrete and that the code writing body elects to use, and an accepted ambient temperature. For adhesive placement in deep failure rate. The characteristic value or 5 percent fractile embedments and/or large-diameter holes, rapid cure has been selected for anchorage design. brought on by high concrete temperatures may result in voids, incomplete embedment of the anchor, and loss of closed crack—condition of a crack in an unloaded test bond. Retarded cure associated with low temperatures may member. Refer to hairline crack. likewise result in loss of adhesive in nondownhole applications. The manufacturer should specify proper procedures for closed crack—crack closure in cracked concrete test permissible installation temperatures as required ensuring members is facilitated by tension forces in the test member of correct anchor placement and attainment of maximum bond the longitudinal reinforcing steel. Following unloading of strength. Refer to gel time. the test member, a residual crack width approximately 0.05 mm will typically remain. The residual crack width

10 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY dry concrete—concrete that, at the time of adhesive testing agency and evaluation agency may be separate anchor installation, is 21 days and older and has not been organizations. exposed to water for the preceding 14 days. load at loss of adhesion—load corresponding to the loss dry concrete—the term “dry concrete” as used herein of adhesion between adhesive and concrete in a tension test is relevant to the establishment of anchor performance in (10.4.4.1). connection with reliability tests. load at loss of adhesion—loss of adhesion is typically elevated concrete temperature—interior temperature of identified as an abrupt change in the load-slip response of an concrete within vicinity of anchor location. Short-term elevated adhesive anchor in a tension test and marks the transition concrete temperatures occur over brief intervals, for example, as from resistance associated primarily with adhesion, or a result of diurnal cycling. Long-term concrete temperatures are chemical bond, to frictional resistance or micro-keying. roughly constant over significant periods of time. Manufacturer’s Printed Installation Instructions elevated concrete temperature—elevated concrete (MPII)—published instructions for correct anchor installation temperatures arise from a number of factors, including sun under all covered installation conditions as supplied in exposure, proximity to operating machinery, or containment product packaging by the manufacturer of the adhesive of liquids or gasses at elevated temperature. anchor system. The MPII shall include information on storage conditions, shelf life, and all restrictions on installation To establish design bond strengths, two classes of elevated conditions (10.22.1). concrete temperature are identified: Manufacturer’s Printed Installation Instructions 1. Where elevated concrete temperatures are transient or (MPII)—for the purposes of this standard, the MPII is the part of a regular cycle of heating and cooling, such as sole source of instruction for the installation of the adhesive day-night temperature rise and fall, they are considered anchor system. It must be included in packaging for the short-term elevated temperatures for the purposes of adhesive anchor system and cannot be supplied in the form this standard; and of supplementary documentation or verbal instruction. The format, text, pictograms, photos, or other graphic devices 2. Where concrete temperatures may remain elevated used to convey the installation procedures should be legible, over weeks or months, they should be considered long- self-explanatory, and understandable for persons having a term elevated temperatures. secondary school or higher education level. It is the respon- sibility of the ITEA to evaluate the MPII and assess its Concrete temperature as an installation parameter is suitability prior to beginning the test program. addressed separately in 8.6 and 8.7. primary testing laboratory—ITEA with primary respon- five percent fractile—a value corresponding to a 5 percent sibility for testing and assessment of an anchor product in probability of nonexceedence with a confidence of 90 percent accordance with this standard. based on a Gaussian distribution for which the population standard deviation is unknown. Refer to characteristic value. primary testing laboratory—while it is permissible for multiple ITEAs to be engaged in the assessment of a single five percent fractile—this section intentionally left blank. adhesive anchor system, one laboratory is responsible for the coordination and overall assessment of the system. gel time—the elapsed time after mixing adhesive material components to onset of significant chemical reaction as pullout failure—a failure mode characterized by the characterized by an increase in viscosity. withdrawal of the anchor element from the concrete without rupture of the embedded part—for example, the threaded rod gel time—mechanical disturbance of the chemical reaction or reinforcing bar—and without formation of a full-depth after the gel time has elapsed and before the attainment of conical breakout surface. The formation of limited-depth full cure as defined by the cure time is likely to result in conical breakout surfaces shall also be considered as pullout impairment of adhesive material mechanical properties. failures. hairline crack—a crack in an unloaded test member pullout failure—visual assessment of pullout failure is resulting from tension loading of the member. difficult in many cases. This standard compares the predicted concrete breakout strength with the maximum hairline crack—hairline cracks in test members used for bond strength, as based on the characteristic limiting bond anchor testing in cracks are typically 0.05 mm. The residual stress, to determine pullout failure. crack width associated with a hairline crack may be influenced by the presence of anchors installed in the crack path and the saturated concrete—concrete that, at the time of adhesive crack width cycling history of the test member. anchor installation, has been exposed to water over a sufficient length of time to have the maximum possible amount of Independent Testing and Evaluation Agency (ITEA)— absorbed water into the concrete pore structure to a depth a laboratory accredited in conformance with requirements in equal to the anchor embedment depth. Chapter 12 having responsibility for testing and assessment of an anchor product in accordance with the criteria in this saturated concrete—the term “saturated concrete” as standard. used herein is relevant to the establishment of anchor perfor- mance in connection with reliability tests. Independent Testing and Evaluation Agency (ITEA)— laboratories engaged in testing and evaluation of adhesive shelf life—recommended time that adhesive materials anchor systems must be familiar with the test procedures and may be stored before degradation may begin. Shelf life shall reference standards described in this standard as applicable and have demonstrated conformance with the procedures and policies set forth in ISO 17020 and ISO 17025. The

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 11 be determined by appropriate testing, indicated on the 3.1.2.1 Mandatory round-robin tests for adhesive adhesive anchor system packaging, with required storage anchors shall be performed to establish the effects of conditions described in the MPII. regional variations in concrete on anchor behavior (9.1). shelf life—influenced by storage conditions. The MPII R3.1.2.1 Round-robin tests were introduced in ACI 355.4M should clearly state the storage requirements associated to avoid undue influence of regional concrete composition with predicted shelf life for the adhesive. on anchor tension strength. Round-robin tests followed extensive, but inconclusive, investigations to determine small, intermediate, and large diameters—the smallest, the precise nature of concrete composition influence on intermediate, and largest diameters are to be determined from adhesive anchor performance. Theories regarding this effect the manufacturer’s published or production anchor diameters include variations in concrete porosity, as reflected in the of the tested anchor system. The intermediate diameter shall concrete density, and aggregate hardness. Limited experi- be taken as least 3 mm larger than the smallest diameter and mental evidence indicates these effects may lessen as the the diameter most closely representing the arithmetic mean concrete age increases. of the smallest and largest diameters. Round-robin tests are performed in regional concretes to small, intermediate, and large diameters—this section establish and compare a nominal bond strength for generally intentionally left blank. expected anchor performance against the tested anchor bond strength. Based on round-robin tests (establishing a splitting failure—a concrete failure mode characterized bond strength above or below the ITEA value) the reported by the formation of a planar crack in the concrete parallel to bond strength is adjusted up or down. Refer to 9.1 and 10.4.1 and extending through the axis of the anchor or anchors. for further methodology. standard temperature—23°C ± 4°C. 3.1.2.2 Supplemental assessment tests for multiple statistically equivalent—two groups of test results shall anchor element types (refer to 3.4). be considered statistically equivalent if there are no significant differences between the means and the standard deviations 3.1.2.3 Supplemental assessment tests for alternate of the two groups. Such statistical equivalence shall be drilling methods (refer to 3.5). demonstrated using a one-sided Student’s t-Test at a confidence level of 90 percent. 3.2—Variables and options steel failure—a failure mode characterized by fracture of R3.2 Optional tests are specified in ACI 355.4M. Omission of the anchor element. test member—a concrete element in which anchors are optional tests will result in limitations being placed on use of installed and tested. the adhesive anchor system. test member—this section intentionally left blank. test series—a group of identical anchors tested under 3.2.1 The assessment of a given anchor system in accordance identical conditions. Identical conditions include anchor with ACI 355.4M includes consideration of the following diameter, length, embedment, spacing, edge distance, hole system variables and optional installation and use conditions: diameter and depth, concrete density/weight, test member thickness, and concrete compressive strength. 1. Presence of water during anchor installation— uncracked concrete—for purposes of this standard, a Installation procedures, including hole cleaning concrete test member that is uncracked at the beginning of procedures, are as specified in the MPII. Hole cleaning the test. procedures typically include vacuuming, evacuation with forced air, and brushing. Quantification of the CHAPTER 3—GENERAL REQUIREMENTS number, order, and duration of cleaning operations and 3.1—Test organization description of equipment used is required. The default installation condition for verification of the hole 3.1.1 Qualification of an anchor system in accordance with cleaning procedure is dry concrete. Verification in ACI 355.4M evaluates the anchor system under four types of water-saturated concrete is mandatory. Options include tests: installation in water-filled holes and in submerged concrete (7.6 through 7.8 and 7.10 through 7.12). 1. Identification tests to evaluate anchor compliance with manufacturer’s specifications (Chapter 5) 2. Drilling method—The default drilling method uses a rotary hammer drill with carbide bit. Optional drilling 2. Reference tests to obtain baseline values for the methods for assessment includes core drilling and rock evaluation of reliability and service-condition test drilling (3.5). results (Chapter 6) 3. Installation direction—Installation direction is the 3. Reliability tests to assess anchor sensitivity to adverse orientation of the axis of the anchor relative to gravity. installation conditions and long-term loading (Chapter 7) Unless otherwise noted, the installation direction is vertically down. Optional installation directions for 4. Service-condition tests to establish anchor performance assessment extenuation are horizontal and vertical (7.18). under expected service conditions (Chapter 8) 4. Installation temperature—The default concrete R3.1.1 The classification of test types in this standard is temperature range during anchor installation is 10 to identical to that established in ACI 355.2 (ACI Committee 27°C. Options include installation at lower concrete 355 2007). temperatures (8.6). 3.1.2 In addition, the following supplemental service-condi- tion tests (3.1.2.1 through 3.1.2.3) are included (Chapter 9).

12 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 5. Embedment depth and anchor diameter—The anchor concrete conditions, the entire test program outlined in diameters and associated embedment depth range are Table 3.2 must be conducted. specified by the manufacturer within the ranges permitted by this standard (refer to Chapter 1). 3.3.3 Test requirements for adhesive anchors to be assessed to resist seismic loads are defined in Table 3.2. 6. Anchor element type—Anchor element types used in Tables 3.1 and 3.3 may not be used to assess anchors to the anchorage system include different steel material resist seismic loads. types such as carbon and stainless steels, different tensile strengths of the steel, and different anchor 3.4—Assessment for multiple anchor element elements such as threaded rods, reinforcing bars, and types for adhesive anchors internally threaded inserts (3.4). R3.4 When tests are performed on one type of anchor 7. Environmental use conditions—Default conditions are material such as carbon steel-threaded rod and the qualification dry and wet environments with service temperatures is intended to include other types of threaded rod, such as ranging from –40°C to the maximum long- and short- stainless steel or hot-dip galvanized rod, then the testing and term service temperatures corresponding to the assessment of the adhesive anchor system is conducted for temperature categories given in Table 8.1. the primary rod type (usually carbon steel) and supplementary tests are conducted using the second rod type in accordance 8. Chemical exposure—The default exposure condition with Table 3.4. This abbreviated testing and assessment is is high alkalinity in a wet environment. The optional primarily intended to address change in the torque-tension exposure condition is sulfur dioxide (8.8). relationship associated with different rod materials, coatings, and thread types (ANSI/ASME B1.1 1989). 9. Concrete condition—Options include uncracked concrete or uncracked and cracked concrete. If the additional testing performed using Table 3.4 indicates significant differences between the bond stresses of the two 10. Loading—Default loading conditions are static anchor elements, then repeat the entire test program for the loading including sustained loads. Qualification for anchor element. seismic loading is optional in conjunction with qualifi- cation for cracked concrete (8.12 and 8.13). 3.4.1 When the assessment encompasses multiple anchor element material types such as carbon and stainless 11. Member thickness—The default minimum member steel, the entire assessment shall be permitted to be thickness is hef,min + Δh. Refer to 1.2.1 for hef,min and performed with one anchor type; however, the other anchor 10.7 for Δh. For smaller values of Δh, tests shall be element types shall be subjected to additional tests in accor- conducted to verify that holes may be drilled and dance with Table 3.4. anchors installed without concrete spalling on the backside of the member for specific ratios of hef /h. 3.5—Assessment for alternate drilling methods R3.5 Hammer drilling and rock drilling are assumed to 3.2.2 Limitations on conditions of use as a function of which optional tests are performed are described in 10.22.1. produce similar hole wall characteristics from the standpoint of bond strength development. Drilling with diamond core 3.3—Test requirements bits, dry or wet, produces a smoother hole wall with a layer of R3.3 This standard makes a fundamental distinction drilling slurry or dust that can impair bond development. between anchors qualified for use exclusively in concrete 3.5.1 Qualification of anchors using drilling methods other that is expected to remain uncracked over the service life of than carbide bit rotary-hammer must meet the requirements the anchorage and anchors qualified for use in concrete that noted in 3.5.1.1 and 3.5.1.2. may be cracked or uncracked over the service life of the anchorage. 3.5.1.1 Perform supplemental tests in accordance with Table 3.5 using the alternate drilling method. Install anchors Table 3.1 addresses qualification for use in uncracked in accordance with the MPII. concrete only, while Table 3.2 addresses cracked concrete qualification as well as qualification for seismic loading. 3.5.1.2 Results of supplemental testing required in Note that qualification for seismic loading can only be Table 3.5 must be compared to corresponding tests conducted conducted in the context of qualification for cracked concrete. using a carbide rotary-hammer bit. If the comparison does Table 3.3 provides an abbreviated test program for anchors to not indicate statistical equivalence in test results between be qualified for use in cracked concrete, but without the option carbide rotary-hammer drilling and the alternative drilling to achieve qualification for seismic loading. method, then the alternative drilling method must be qualified using the test requirements of 3.3. 3.3.1 Test requirements for adhesive anchors assessed to resist static loads in uncracked concrete conditions are There are, however, two exceptions: 1) testing for shear defined in Table 3.1. capacity of the anchor element need not be repeated. Additional testing for shear capacity of the anchor element 3.3.2 Test requirements for adhesive anchors assessed to is not required and may be omitted (Table 3.1, Test 12; resist static loads in both cracked and uncracked concrete Table 3.2, Test 16; or Table 3.3, Test 13); and 2) testing conditions are defined in Tables 3.2 and 3.3. The reduced test using a carbide rotary-hammer drill shall also be valid for program in Table 3.3 is associated with a predefined and percussive drilling, like pneumatic rock drilling, without conservative value for the ratio of characteristic limiting supplementary tests. Testing using percussive drilling, bond stresses in uncracked and cracked concrete. For optimi- zation of the predicted strength of anchors in cracked

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 13 Table 3.1—Test program for evaluating adhesive anchor systems in uncracked concrete Test no. Test reference Testing Test parameters Assessment fc* Minimum Purpose Load and sample size hef† nmin αreq displacement Reference tests 1a Chapter 6 Reference tension in Tension, confined, single anchor away — — low min Five per low-strength concrete from edges max concrete batch 1b Chapter 6 Reference tension in Tension, confined, single anchor away — — high min Five per high-strength concrete from edges concrete batch Reliability tests 2a 7.5 Sensitivity to hole cleaning, dry Tension, confined, single anchor away 10.4.6 10.4.2 low max Five‡ substrate from edges 10.4.4 2b 7.6 Sensitivity to hole cleaning, installation Tension, confined, single anchor away 10.4.6 10.4.2 low max Five‡ 10.4.4 in water-saturated concrete from edges 2c 7.7 Sensitivity to hole cleaning, installation Tension, confined, single anchor away 10.4.6 10.4.2 low max Five‡ in a water-filled hole§ 10.4.4 from edges 2d 7.8 Sensitivity to hole cleaning, Tension, confined, single anchor away 10.4.6 10.4.2 low max Five|| installation in submerged concrete§ from edges 10.4.4 2e 7.9 Sensitivity to mixing effort Tension, confined, single anchor away 10.4.6 10.4.2 low max Five# from edges 10.4.4 2f** 7.10 Sensitivity to installation Tension, confined, single anchor away 10.4.6 10.4.2 low max Five‡ in water-saturated concrete from edges 10.4.4 2g 7.11 Sensitivity to installation Tension, confined, single anchor away 10.4.6 10.4.2 low max Five‡ in a water-filled hole§ from edges 10.4.4 2h 7.12 Sensitivity to installation in submerged Tension, confined, single anchor away 10.4.6 10.4.2 low max Five|| concrete§ 10.4.4 from edges 3 7.16 Sensitivity to freezing/thawing Sustained tension, residual capacity, 0.90 10.4.2 high min†† Five# conditions confined test 10.4.4 10.10 4 7.17 Sensitivity to sustained load Sustained tension, residual capacity, 0.90 10.4.2 low min†† Five# confined test 10.4.4 10.11 5 7.18 Sensitivity to installation direction§ Tension, confined, single anchor away 0.90 10.4.2 low max Five# from edges 10.4.4 10.12 6 7.19 Torque test‡‡ Application of torque, confined, single — 10.8 high min Five|| anchor away from edges Service-condition tests 7a 8.4 Tension in low-strength concrete Tension, unconfined, single anchor — 10.4.2 low min Five|| away from edges§§ 10.4.4 max 10.4.5 7b 8.4 Tension in high-strength concrete|||| Tension, unconfined, single anchor — 10.4.2 high min Five|| away from edges§§ 10.4.4 10.4.5 8a 8.5 Tension at elevated temperatures Tension, confined, single anchor away — 10.4.2 low min Five# from edges 10.4.4 10.13 8b 8.6 Tension at decreased installation Tension, confined single anchor away — 10.4.2 low min Five# temperature§ from edges 10.4.4 10.14 8c 8.7 Curing time at standard installation Tension, confined single anchor away — 10.4.2 low min Five# 10.4.4 temperature from edges 10.15 9a 8.8 Resistance to alkalinity Slice tests — 10.16 low — Ten# 9b 8.8 Resistance to sulfur§ Slice tests — 10.16 low — Ten# 10 8.9 Edge distance in corner condition to Tension, unconfined single anchor in — 10.17 low min Four|| corner with proximate edges## max develop full capacity 11 8.10 Minimum spacing and edge distance to High installation tension (torque or — 10.18 low min Five|| preclude splitting unconfined tension), two anchors near an edge## 12 8.11 Shear capacity of steel element having a Shear, single anchor away from edges — 10.6 low min Five|| non-uniform cross section*** 13 9.1 Round-robin tests for regional concrete Tension, confined and unconfined — 10.4.1 low††† 7da Five# variation single anchor away from edges 14 9.2 Minimum member thickness§ Installation tests## — 10.7 low max Ten|| *For definition of high- and low-strength concrete, refer to 4.3.4. †Where MPII specifies multiple ‡Test small, medium, and large embedment depths for single anchor diameter, test anchor at minimum or maximum embedment depth as noted, whereby hef,max/hef,min ≤ 5.0 (4.7.2). diameters. §Optional test. ||Test all diameters. #Test the nominal M12 diameter or the smallest nominal diameter if it is larger than M12. For overhead and horizontal orientations, test the largest diameter for which recognition is sought. For tests conducted in accordance with 9.1, tests shall be performed with a nominal M12 anchor only. **Test 2f may be omitted if Test 2g is performed. ††Refer to 4.7.2.2. ‡‡Refer to 3.4 for multiple anchor element types. §§Alternatively, tests may be performed as confined tests. ||||Tests are optional if test results of Test 1b can be shown to be statistically equivalent to or greater than the results of Test 1a. If Test 7b is not performed, limit the calculated anchor t*#e#*nU*Tssieoesnmt riiesnsirimesqtuaunmicreemdteoomnfcbl′ye=rfot1hr7icaMknncPheasosrreshghmaairnvdiflneogsrstahoefcsrteohsetse-isnstes-p.ctliaocneacloanrcerae,twe sitthreinngftihv.e anchor diameters of the shear failure plane, that is less than that of a threaded bolt having the same nominal diameter as the anchor. †††Test in concrete having a measured compressive strength of 21 ± 3.5 MPa at the time of testing.

14 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Table 3.2—Test program for evaluating adhesive anchor systems for cracked and uncracked concrete (cont.) Test Test Testing Test parameters Crack Assessment fc* Minimum no. reference Purpose width Δw, sample size Load and hef† nmin mm displace- αreq ment Reference tests 1a Chapter 6 Reference tension in low-strength Tension, confined, single anchor away — — — low min Five per max concrete batch concrete from edges 1b Chapter 6 Reference tension in low-strength, Tension, confined, single anchor away 0.3 — — low min Five per concrete batch cracked concrete from edges 1c Chapter 6 Reference tension in high-strength Tension, confined, single anchor away — — — high min Five per concrete batch concrete from edges 1d Chapter 6 Reference tension in high-strength, Tension, confined, single anchor away 0.3 — — high min Five per cracked concrete‡ concrete batch from edges Reliability tests 2a 7.5 Sensitivity to hole cleaning, dry substrate Tension, confined, single anchor away — 10.4.6 10.4.2 low max Five§ from edges 10.4.4 2b 7.6 Sensitivity to hole cleaning, installation Tension, confined, single anchor away — 10.4.6 10.4.2 low max Five§ 10.4.4 in water-saturated concrete from edges 2c 7.7 Sensitivity to hole cleaning, installation Tension, confined, single anchor away — 10.4.6 10.4.4 low max Five§ in a water-filled hole|| 10.4.4 from edges 2d 7.8 Sensitivity to hole cleaning, installation Tension, confined, single anchor away — 10.4.6 10.4.4 low max Five# in submerged concrete|| from edges 2e 7.9 Sensitivity to mixing effort Tension, confined, single anchor away — 10.4.6 10.4.2 low max Five** from edges 10.4.4 2f †† 7.10 Sensitivity to installation Tension, confined, single anchor away — 10.4.6 10.4.2 low max Five§ in water-saturated concrete from edges 10.4.4 2g 7.11 Sensitivity to installation Tension, confined, single anchor away — 10.4.6 10.4.2 low max Five§ in a water-filled hole|| from edges 10.4.4 2h 7.12 Sensitivity to installation in submerged Tension, confined, single anchor away — 10.4.6 10.4.2 low max Five# concrete|| 10.4.4 from edges 3 7.13 Sensitivity to crack width in Tension, confined, single anchor away 0.5 0.80 10.4.4 low min Five§ low-strength concrete from edges 10.4.4 4 7.14 Sensitivity to crack width in Tension, confined, single anchor away 0.5 0.80 10.4.2 high min Five§ high-strength concrete‡ from edges 10.4.4 5 7.15 Sensitivity to crack width cycling Sustained tension, single anchor away 10.4.2 low min Five # from edges, residual capacity, 0.1 to 0.3 0.90 10.4.4 confined test 10.9 6 7.16 Sensitivity to freezing/thawing Sustained tension, residual capacity, — 10.4.2 Five** conditions confined test 0.90 10.4.4 high min‡‡ 10.10 7 7.17 Sensitivity to sustained load Sustained tension, residual capacity, — 10.4.2 Five** confined test 0.90 10.4.4 low min‡‡ 10.11 8 7.18 Sensitivity to installation direction|| Tension, confined, single anchor away — 10.4.2 low max Five** from edges 0.90 10.4.4 10.12 9 7.19 Torque test§§ Application of torque, confined, single — — 10.8 high min Five# anchor away from edges Service-condition tests 11a 8.4 Tension in low-strength concrete Tension, unconfined, single anchor — — 10.4.2 low min Five# away from edges 10.4.4 max 10.4.5 11b 8.4 Tension in high-strength concrete‡ Tension, unconfined, single anchor — 10.4.2 Five# away from edges — 10.4.4 high min 10.4.5 11c 8.4 Tension in low-strength, cracked Tension, unconfined, single anchor 0.3 10.4.2 Five# concrete away from edges — 10.4.4 low min 10.4.5 11d 8.4 Tension in high-strength, cracked Tension, unconfined, single anchor 0.3 10.4.2 Five# concrete‡ away from edges — 10.4.4 high min 10.4.5 12a 8.5 Tension at elevated temperatures Tension, confined single anchor away — 10.4.2 Five ** from edges — 10.4.4 low min 10.13 12b 8.6 Tension at decreased installation Tension, confined single anchor away — 10.4.2 Five** temperature|| from edges — 10.4.4 low min 10.14 12c 8.7 Curing time at standard installation Tension, confined single anchor away — 10.4.2 Five** — 10.4.4 low min temperature from edges 10.15

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 15 Table 3.2—Test program for evaluating adhesive anchor systems for cracked and uncracked concrete (cont.) Test Test Testing Test parameters Crack Assessment fc* Minimum no. reference Purpose width Δw, sample size Load and hef† nmin mm displace- αreq ment 13a 8.8 Resistance to alkalinity Slice tests — — 10.16 low — Ten** 13b 8.8 Resistance to sulfur|| Slice tests — — 10.16 low — Ten** 14 8.9 Edge distance in corner condition to Tension, unconfined single anchor in — — 10.17 low min Four# corner with proximate edges## max develop full capacity 15 8.10 Minimum spacing and edge distance to High installation tension (torque or — — 10.18 low min Five# preclude splitting unconfined tension) two anchors near an edge## 16 8.11 Shear capacity of anchor element having Shear, single anchor away from — — 10.6 low min Five# a non-uniform cross section edges*** 17 8.12 Seismic tension|| Pulsating tension, single anchor away 0.5 — 10.4.2 low min Five# from edges 10.4.4 max 10.19 18 8.13 Seismic shear|| Alternating shear, single anchor away 0.5 — 10.20 low min Five§ from edges 19 9.1 Round-robin tests for regional concrete Tension, confined and unconfined — — 10.4.1 low††† 7da Five** variation single anchor away from edges 20 9.2 Minimum member thickness|| Installation tests## — — 10.7 low max Ten# *For definition of high- and low-strength concrete, refer to 4.3.4. †Where MPII specify multiple embedment ‡Tests are optional if test results of Test 1c depths for single anchor diameter, test anchor at minimum or maximum embedment depth as noted, whereby hef,max/hef,min ≤ 5.0 (4.7.2). can be shown to be statistically equivalent to or greater than results of Test 1a. If any of Tests 1d, 4, 11b, and 11d are not performed, limit calculated anchor tension resistance to fc′ = 17 MPa. §Test small, medium, and large diameters. ||Optional test. #Test all diameters. **Test the nominal M12 diameter or the smallest nominal diameter if it is larger than M12. For overhead and horizontal orientations, test the largest diameter for which recognition is sought. For tests conducted in accordance with Section 9.1, tests shall be performed with a nominal M12 anchor only. ††Test 2f may be omitted if Test 2g is performed. ‡‡Refer to Section 4.7.2.2. §§Refer to Section 3.4 for multiple anchor element types. *#*#U*Tseesmt iisnirmequumiremdeomnblyerfothricaknnchesosrshhmainvifnogr these tests. area, within five anchor diameters of the shear failure plane, that is less than that of a threaded bolt having the same a cross-sectional nominal diameter as the anchor. †††Test in concrete having a measured compressive strength of 21 MPa ± 3.5 MPa at the time of testing. Table 3.3—Reduced test program for evaluating adhesive anchor systems in cracked and uncracked concrete (cont.) Testing Crack Assessment Minimum Purpose Test Test Test parameters width Δw, Load and fc* hef† sample size no. reference mm αreq displacement nmin Reference tests 1a Chapter 6 Reference tension in Tension, confined, single anchor — — — low min Five per low-strength concrete away from edges max concrete batch 1b Chapter 6 Reference tension in Tension, confined, single anchor — — — high min Five per high-strength concrete away from edges concrete batch Reliability tests 2a 7.5 Sensitivity to hole cleaning, Tension, confined, single anchor — 10.4.6 10.4.2 low max Five‡ 10.4.4 dry substrate away from edges 2b 7.6 Sensitivity to hole cleaning, Tension, confined, single anchor — 10.4.6 10.4.2 low max Five‡ installation in water-saturated away from edges 10.4.4 concrete 2c 7.7 Sensitivity to hole cleaning, Tension, confined, single anchor — 10.4.6 10.4.2 low max Five‡ installation in a water-filled hole§ 10.4.4 away from edges 2d 7.8 Sensitivity to hole cleaning, Tension, confined, single anchor — 10.4.6 10.4.2 low max Five|| installation in submerged away from edges 10.4.4 concrete§ 2e 7.9 Sensitivity to mixing effort Tension, confined, single anchor — 10.4.6 10.4.2 low max Five# away from edges 10.4.4 2f** 7.10 Sensitivity to installation in Tension, confined, single anchor — 10.4.6 10.4.2 low max Five‡ 10.4.4 water-saturated concrete away from edges 2g 7.11 Sensitivity to installation in a Tension, confined, single anchor — 10.4.6 10.4.2 low max Five‡ water-filled hole§ 10.4.4 away from edges 2h 7.12 Sensitivity to installation in Tension, confined, single anchor — 10.4.6 10.4.2 low max Five|| submerged concrete§ 10.4.4 away from edges

16 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Table 3.3—Reduced test program for evaluating adhesive anchor systems in cracked and uncracked concrete (cont.) Test Test Testing Test parameters Crack Assessment fc* hef† Minimum no. reference width Δw, low min sample size Purpose Load and high min†† 3 7.15 mm αreq displacement low min†† nmin Sensitivity to crack width low max Five|| cycling Sustained tension, single anchor 10.4.2 high min away from edges, residual 0.1 to 0.3 0.90 10.4.4 Five# capacity, confined test 10.9 Five# 4 7.16 Sensitivity to freezing/thawing Sustained tension, residual — conditions capacity, confined test 10.4.2 Five# 0.90 10.4.4 Five|| 5 7.17 Sensitivity to sustained load Sustained tension, residual — capacity, confined test 10.10 Five|| 6 7.18 Sensitivity to installation Tension, confined, single anchor -— 10.4.2 Five|| direction§ away from edges 0.90 10.4.4 Five# 7 7.19 Torque test‡‡ Application of torque, confined, — 10.11 single anchor away from edges 10.4.2 Service-condition tests 0.90 10.4.4 8a 8.4 Tension in low-strength concrete Tension, unconfined, single — 10.12 low min anchor away from edges max — 10.8 8b 8.4 Tension in high-strength Tension, unconfined, single — high min concrete§§ anchor away from edges 10.4.2 — 10.4.4 9a 8.5 Tension at elevated temperatures Tension, confined single anchor — low min away from edges 10.5 10.4.2 — 10.4.4 10.5 10.4.2 — 10.4.4 10.13 9b 8.6 Tension at decreased installation Tension, confined single anchor — — 10.4.2 low min Five# temperature§ 10.4.4 away from edges 10.14 9c 8.7 Curing time at standard Tension, confined single anchor — — 10.4.2 low min Five# installation temperature away from edges 10.4.4 10.15 10a 8.8 Resistance to alkalinity Slice tests —— 10.16 low - Ten# 10b 8.8 Resistance to sulfur§ Slice tests — — 10.16 low - Ten# 11 8.9 Edge distance in corner condition Tension, unconfined single — — 10.17 low min Four|| to develop full capacity anchor in corner with proximate max edges## 12 8.10 Minimum spacing and edge High installation tension (torque — — 10.18 low min Five|| distance to preclude splitting or unconfined tension), two anchors near an edge## 13 8.11 Shear capacity of anchor element Shear, single anchor away from — — 10.6 low min Five|| having a non-uniform cross edges*** section 14 9.1 Round-robin tests for regional Tension, confined and unconfined — — 10.4.1 low††† 7da Five# concrete variation single anchor away from edges 15 9.2 Minimum member thickness§ Installation tests## —— 10.7 low max Ten|| *For definition of high- and low-strength concrete, refer to 4.3.4. †Where MPII specify ‡Test small, medium, multiple embedment depths for single anchor diameter, test anchor at minimum or maximum embedment depth as noted, whereby hef,max/hef,min ≤ 5.0 (4.7.2). and large diameters. §Optional test. ||Test all diameters. #Test nominal M12 diameter or smallest nominal diameter if it is larger than M12. For overhead and horizontal orientations, test largest diameter for which recognition is sought. For tests conducted in accordance with 9.1, tests shall be performed with nominal M12 anchor only. **Test 2f may be omitted if Test 2g is performed. ††Refer to 4.7.2.2. ‡‡Refer to 3.4 for multiple anchor element types. §§Tests are optional if test results of Test 1b can be shown to be statistically equivalent to or greater than results of Test 1a. If Test 8b is not performed, limit calculated anchor #*te*#n*UTssieoesnmt riiesnsirimesqtuaunmicreemdteoomnfcbl′ye=rfot1hr7iacMnkcnPheaos.srshhmainvifnogr these tests. area within five anchor diameters of the shear failure plane that is less than that of threaded bolt having same nominal cross-sectional diameter as anchor. †††Test in concrete having measured compressive strength of 21 ± 3.5 MPa at time of testing.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 17 Table 3.4—Additional tests required for assessment of multiple anchor element types in accordance with 3.4 Nature of variation from tested anchor element* Material† Geometry Surface coating Reference Test no. Purpose Requirement — X X Table 3.1 6 — X X Table 3.2 9 Torque test‡ Refer to Section 10.8 — X X Table 3.3 7 — X X Table 3.1 10 — X X Table 3.2 14 Corner test§ Refer to Section 10.17 — X X Table 3.3 11 — X X Table 3.1 11 Minimum spacing and edge distance§ — X X Table 3.2 15 Refer to Section 10.18 — X X Table 3.3 12 X X — Table 3.1 12 Shear test to determine shear Required for anchor elements with X X — Table 3.2 16 capacity as governed by steel reduced cross section; refer to X X — Table 3.3 13 failure Section 8.11 X X — Table 3.2 18 Seismic shear test Optional test; refer to Section 10.20 *In cases where anchor element varies in more than one characteristic (for example, material, geometry, or surface coating), test requirements indicated for each variation shall apply. †For stainless steels, conduct tests as required for change in geometry. ‡In cases where results of torque testing can show statistical equivalence to tested anchor element type, repetition of corner and minimum spacing and edge distance tests shall be permitted to be omitted. §Where reference test results indicate that anchor element has statistically meaningful influence on bond stress, repeat entire test program for anchor element. Table 3.5—Required supplemental tests for each alternative drilling method Test numbers to be conducted for each alternative drilling method Table no. Reference Reliability/installation safety Reliability/crack width —— 3.1 1a 1b — — 2a 2b 2c* 2d* 2f 2g* 2h* 34 2h* —— 3.2 1a 1b 1c 1d 2a 2b 2c* 2d* 2f 2g* 2h* 3.3 1a 1b 1c 1d 2a 2b 2c* 2d* 2f 2g* * Optional tests required only if conditions of use associated with these tests are to be included for recognition. however, shall not be valid for rotary-hammer drilling facility and verify the samples are representative of production without supplemental tests, as described in 3.5. of the manufacturer as supplied to the marketplace. CHAPTER 4—REQUIREMENTS R4.2.1 Practical considerations may dictate that sampling FOR TEST SPECIMENS, be performed at a distribution center instead of the manufac- turing facility. Due diligence should be exercised by the ANCHOR INSTALLATION, AND TESTING ITEA to ensure the samples are representative of production 4.1—Testing by ITEA and manufacturer in all cases. Methods for ensuring the integrity of randomly sampled product throughout the custody chain include The minimum number of reference, reliability, and stamping or signing over the packaging, recording serial service-condition tests given in Tables 3.1 through 3.3 of this and batch numbers, and photographing the sampled product. standard shall be performed by the ITEA (Chapter 12). Results of additional tests performed by the manufacturer 4.2.2 To test newly developed anchor adhesives not in can be considered in the evaluation, only if the results are production, use samples produced by the expected production statistically equivalent to those of the ITEA. methods. After production has begun, perform identification and reference tests to verify the constituent materials have R4.1 It is required that the testing program be performed not changed and performance of the production anchors is under the guidance and direction of a single qualified ITEA statistically equivalent to the anchors originally evaluated. with experience in anchor testing. The primary testing labo- ratory may have specific tests performed by other qualified R4.2.2 The use of preproduction prototypes for testing to laboratories, but retains the overall responsibility for testing develop qualification data is foreseen by ACI 355.4M. The and evaluating the anchor system. Tests performed in the prototypes, however, must be produced using the production manufacturer’s laboratory shall only be considered for methods foreseen for the full-scale production and must be improvement of the statistical accuracy of a test series and accompanied by a complete MPII. Supplemental testing of must be shown to belong to the same data population by the production product to confirm validity of the prototype establishing statistical equivalency with test data developed tests is required. by the primary laboratory or other ITEAs. 4.2.3 When internally threaded anchors are supplied 4.2—Test samples without fastening items such as bolts, threaded rods, or nuts, 4.2.1 The ITEA (Chapter 12) shall randomly select the manufacturer shall specify the fastening items to be used. anchors for testing from a manufacturing or distribution

18 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 4.2.4 The sample sizes given in Tables 3.1 through 3.3 • Low-strength concrete: 17 to 28 MPa are the minimum required to satisfy ACI 355.4M. The • High-strength concrete: 46 to 60 MPa sample size may be increased at the discretion of the ITEA or manufacturer. R4.3.4 The influence of concrete compressive strength (as measured in a uniaxial compressive test) on anchor bond 4.2.5 Where tension tests on anchor elements are required strength is dependent on specific bonding properties of the to establish steel properties, a minimum of three replicates adhesive anchor system and must be established by test. shall be performed. Tests are conducted in low- and high-strength concrete to assess whether there is a direct or inverse correlation 4.3—Concrete for test members between concrete compressive strength and bond strength 4.3.1 Concrete used in testing shall meet the requirements for the adhesive anchor system in question. of 4.3. To assess the performance of an anchor for use in 4.3.5 Test members shall be at least 21 days old at the time concrete outside of the scope of ACI 355.4M, additional of anchor installation and testing. tests consistent with the requirements of Tables 3.1 through 3.3 shall be conducted with that concrete. R4.3.5 Testing of anchors in concrete less than 21 days old constitutes testing in a nonstandard concrete. R4.3.1 As a rule, testing is conducted in concrete using portland cement, normalweight aggregate, and natural sand 4.3.6 Refer to 9.1 for additional requirements in conjunction without cement replacements, admixtures, or other enhance- with round-robin testing for adhesive anchors. ments. The results of these tests are assumed to be generally applicable to a wide range of concrete mixture designs with 4.3.7 It shall be permitted to test anchors, when required, modification factors applied to the bond strength or concrete in test members cast of concrete with a nominal compressive breakout strength where applicable. Where specific qualifi- strength of 14 MPa; however, the results may not be normal- cation is desired for anchors used in lightweight concrete or ized for any other strength concrete. concrete containing cement replacements, admixtures, or other enhancements such as to support increased design R4.3.7 ACI 318M currently specifies a minimum concrete values over those provided for in ACI 318M, the test strength of 17 MPa. In prior codes, the minimum concrete program must be repeated using mixture designs that employ compressive strength was 14 MPa. Testing in concrete with the lightweight aggregate, cement replacement, admixture, a compressive strength of 14 MPa may be necessary to validate or enhancement in question. the use of anchors in existing structures. The results of tests obtained in 14 MPa concrete may not be increased for use of 4.3.2 Coarse and fine aggregates in concrete shall comply anchors in higher concrete strengths. with ASTM C33/C33M. The aggregate description shall include rock and mineral components, shape, hardness, and 4.4—Requirements for test members maximum size and grading specification. Use a maximum 4.4.1 Test members shall conform to the requirements of coarse aggregate size of either 19.0 or 25.0 mm. ASTM E488. Where the requirements of ASTM E488 R4.3.2 The influence of aggregate type on bond strength is conflict with this standard, the provisions of this standard not well understood. Round-robin tests are required to minimize shall take precedence. the potential impact of locally favorable or unfavorable aggregate types on the results of qualification testing. R4.4.1 ASTM E488 establishes general procedures for the testing of anchors in tension and shear. 4.3.3 For general qualification for use of the anchor system in normalweight concrete, use portland cement 4.4.2 Reliability tests and reference tests to which they are conforming to ASTM C150/C150M. The concrete mixture compared shall be conducted in the same batch of concrete. shall not include cement replacements such as slag cement, fly ash, and silica fume or limestone powder. If a concrete R4.4.2 Batch control (refer to Fig. R.4.1) is required for mixture is used for test members that do not conform to the reference tests to ensure that the resultant α values reflect mixture requirements listed herein, a description of the actual variations in anchor behavior, not concrete composition. concrete mixture components and proportions shall be included in the test report. In this case, qualification will be 4.4.3 Casting, curing, and strength determination of test specific to the tested concrete mixture. members R4.3.3 Use of blended cements constitutes a nonstandard 4.4.3.1 Cast test member either horizontally or vertically. If concrete mixture design. Use of lightweight aggregates can the test member is cast vertically, limit the maximum height result in a reduction of bond strength. Where bond values in of a concrete lift to 1.5 m. excess of those specified in ACI 318M, Appendix D, for adhesive anchors in lightweight concrete are required, these R4.4.3.1 Casting of test members in the vertical position must be based on testing in lightweight concrete. provides for formed surfaces on the top and bottom sides of the test member and minimizes the effect of irregularities in 4.3.3.1 For qualification of anchors in lightweight the surface concrete on anchor performance. Care should be concrete, all tests shall be conducted in lightweight concrete exercised in vertical casting that the casting process does unless the default values in ACI 318M, Appendix D, are used. not result in concrete with significant strength variation due to segregation and bleeding effects, especially in the case of 4.3.4 Test anchors in test members cast of concrete within lower-strength concrete. two nominal compressive strength ranges: 4.4.3.2 Sample, mold, and cure compressive strength cylinders in accordance with ASTM C31/C31M. Cure cylinders to the same environmental conditions as the test member. Remove molds from cylinders concurrent with removal of forms and curing covers from the test member.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 19 Fig. R4.1—Concept of concrete batches. Fig. 4.1—Example of test slab for testing in cracked concrete. 4.4.3.3 Determine test member concrete compressive so there is no influence on the anchor performance. Refer to strength at the time of anchor testing from compression tests Fig. 4.1 for an example test slab configuration. conducted on concrete cylinders in accordance with ASTM C39/C39M or cores extracted from the test member in R4.4.5 For additional guidance on preparing and testing accordance with ASTM C42/C42M. The results of tests on in cracked concrete, refer to Eligehausen et al. (2004). cylinders and cores shall not be combined for the establishment of the mean compressive strength at a given concrete age. 4.4.5.1 Control the crack width using embedded reinforcing Determine mean strength test values from: (a) linear interpola- bars oriented perpendicular to the intended crack plane and tion of a test series using the beginning and ending tests as distributed symmetrically over the test member cross section. endpoints; or (b) strength-age relationships developed using The ratio of tension reinforcement for top and bottom layers to compression tests of concrete test members at various test ages. the area of the crack plane shall be approximately 1 percent. R4.4.3.3 Cylinder compressive strengths are preferable 4.4.5.2 The crack control reinforcement shall be to concrete cores for the determination of member permitted to cross the potential concrete cone breakout compressive strength. The potential differences in measured surface associated with the test anchor. The centerline-to- compressive strength resulting from tests on cores or on centerline distance between any crack control reinforcement cylinders should be accounted for. and the anchor shall not be less than 0.4hef. Greater values for spacing of reinforcement are allowed as in the case of 4.4.4 Test members for tests in uncracked concrete—Test narrow concrete components, for example: members for tests in uncracked concrete shall be unreinforced except as required to permit efficient handling of the test width x depth = 500 mm x 250 mm member or distribution of reaction loads from test equipment. Position such reinforcement so that the capacity of the tested where it is ensured that planar cracks of uniform width anchor is not affected. For concrete breakout failure, this throughout the thickness of the component are produced and requirement is satisfied for anchors tested in tension if the the crack width requirements of ACI 355.4M are satisfied. reinforcement is located outside of a virtual cone projecting Furthermore, smaller values for center-to-center distance from the embedded end of the anchor to the concrete surface between reinforcement and anchor are allowed in the case of with an internal vertex angle of 120 degrees. Additionally, deep embedments where the anchorage mechanism is not for splitting failure, reinforcement shall be omitted between influenced by the reinforcement. It shall be permitted to the anchor location and the concrete edge. R4.4.4 Positioning of reinforcement as required for safe transportation of the test member should consider the potential formation of concrete breakout surfaces. Where anchors are to be tested in tension, reinforcement should be placed near the surface and toward the outer edges of the member. Where anchors are to be tested in shear, reinforcement should not be placed near the surface or corners of the test member. 4.4.5 Test members for tests in cracked concrete—Test members for tests in cracked concrete shall be designed to produce cracks of reasonably constant width throughout the thickness of the component. The cracks should be spaced sufficiently apart to facilitate testing of individual anchors placed in a crack without influence from adjacent cracks. For test members that use internal reinforcement to control the crack width or for specimen handling, place the reinforcement

20 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Fig. 4.2—Example of test rig for testing in cracked concrete. 4.5.1.2 Install anchors in a formed face of the concrete or in concrete with a steel-troweled finish. debond reinforcement over a length of 75 mm on either side of the anticipated crack plane location using tape, plastic R4.5.1.2 Testing of anchors in shear and in confined tubing, or other debonding agents. tension should be conducted on a flat, smooth concrete surface. Preferably, formed concrete surfaces should be 4.4.5.3 An acceptable method for crack formation and used for shear testing. crack opening is described in 4.4.5.4. Other methods shall be permitted subject to the requirements of ACI 355.4M. 4.5.1.3 Drilled holes for anchors shall be within six degrees of perpendicular to the surface of the concrete test member. 4.4.5.4 Initiate and control the crack progression with planar sheet metal shapes, or crack initiators, placed in the R4.5.1.3 The allowance of six degrees in the drilling angle formwork prior to casting of the test member. Position crack is intended to permit use of a hand-held hammer drill. It is not initiators so the capacity of the tested anchor is not affected intended that anchors should be installed with a six-degree tilt by their presence. Extend tension reinforcing as required in as a means of enhancing resistance to tension loads. 4.4.5 beyond the ends of the test member to facilitate application of external tension loads directly to the reinforce- 4.5.1.4 Components of the anchor on which the reliability ment. Apply external loading to both ends of the reinforce- and capacity depend shall not be exchanged. Bolts, nuts, and ment to facilitate development of uniform strain over the washers not supplied with the anchors shall conform to the length of the reinforcing. External loads for crack opening specifications given by the manufacturer, which shall be shall not be reacted against the test member. Support the test included in the test report. member to permit uniform tension strain distribution over the length of the test member. Refer to Fig. 4.2 for an R4.5.1.4 Substitution of bolts, nuts, and washers to example test setup. achieve bond failure is permitted. 4.4.5.5 The average crack width for each test series, 4.5.2 For installation of anchors in cracks, follow measured by the two-crack measurement devices for each procedures in R4.5.2. anchor before the load application, shall be equal to or greater than the specified crack width for that test series. R4.5.2 The creation of planar cracks in the test member is Individual crack widths shall be within ±15 percent of the a matter of experience and may be influenced by the position specified crack width for the test series. and type of crack inducers, the type and position of reinforce- ment, and the method used to generate the necessary tensile 4.5—Anchor installation stresses in the concrete. Positioning of the anchor in the 4.5.1 General requirements crack is likewise a matter of judgment. Ideally, the crack 4.5.1.1 Install anchors according to the MPII, except as runs vertically down the centerline axis of the anchor over its entire length. For anchors to be tested in tension, deviation otherwise required in ACI 355.4M. of the crack position from the anchor centerline should be R4.5.1.1 The MPII should be the sole source of information limited to the surface of the member. For anchors to be tested in shear, it is more important that the crack transect for the specified anchor installation unless modified by this the anchor position at the concrete surface. These conditions standard. are best confirmed using a boroscope. 4.5.2.1 With the test member unloaded, drill the hole for the anchor in a hairline crack that is sufficiently planar to ensure the crack will approximately bisect the anchor location over the embedment depth of the anchor. 4.5.2.2 Visually verify positioning of the anchor in the crack before installation by using a boroscope or similar device. 4.5.3 Unless otherwise specified in ACI 355.4M, adhesive anchors shall not be torqued prior to testing. R4.5.3 Unlike torque-controlled expansion anchors, adhesive anchors do not require the application of torque for proper set. 4.6—Drill bit requirements R4.6 Unlike some types of expansion anchors, adhesive anchors are generally insensitive to minor variations in drilled hole diameter. Bit wear should, nevertheless, be monitored during the test program. 4.6.1 Drill holes with a rotary-percussive hammer drill using carbide-tipped, hammer-drill bits meeting the requirements of ANSI B212.15. R4.6.1 For drill bits not covered by ANSI B212.15, for example, core bits, the ITEA shall measure and report the cutting diameter of the bits.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 21 4.7—Test methods drilling methods may be used as appropriate. Seal the interface 4.7.1 Test anchors in conformance with ASTM E488 and between the blocks. this standard. Where differences occur, ACI 355.4M shall 1. Clean the hole in accordance with the procedures take precedence over ASTM E488. The recorded displace- described in the MPII (Fig. 4.3(b)); ments should be corrected so that they represent the displacement at the concrete surface. 2. Perform adhesive injection in accordance with the procedures described in the MPII. Limit injection depth R4.7.1 ASTM E488 provides general guidelines for testing to the bottom block B (Fig. 4.3(c)); anchors in tension and shear. It does not contain specific instructions for many of the tests described in this standard. 3. Remove the upper block A and install the anchor element in accordance with the procedures described in 4.7.2 Configure tension tests used to establish the characteristic the manufacturer’s published installation instructions limiting bond stress so that bond failure is the controlling (Fig. 4.3(d)); and mode of failure. 4. Perform a confined tension test to failure (Fig. 4.3(e)). R4.7.2 In general, the objective of tension tests in ACI R4.7.2.1.2 The use of stacked concrete blocks enables 355.4M is to measure the tension resistance of the adhesive anchor as governed by bond strength. Where either steel or duplication of installation conditions, with respect to hole concrete breakout failures occur, it may be assumed that the depth, while still enabling tension testing that results in bond maximum potential bond strength associated with the adhesive failure as opposed to failure of the anchor element. Other anchor system is not reflected in the measured peak load. methods may be used subject to assessment by the primary testing laboratory. 4.7.2.1 To avoid steel failure, unconfined and confined tension tests may be performed with an anchor element 4.7.2.2 Proof of maximum bond stress for freezing-and- having a documented strength exceeding the product thawing and sustained load tests—For establishing the specification, subject to: 1) the geometry and coatings of the sustained load applied in freezing-and-thawing and substitute anchor element shall be identical to the product sustained load, tests and all other test series where hef,min is specification; or 2) it shall be demonstrated that the substitute specified in Table 3.1, 3.2, or 3.3, it shall be demonstrated anchor element does not affect the function or performance that Eq. (4-1) is fulfilled for the hef,min value used. If Eq. (4-1) of the anchor. is not satisfied with the results of unconfined tests, increase the embedment depth until Eq. (4-1) is satisfied; however, R4.7.2.1 For deeper embedments, it may be necessary to steel failure should be avoided in all tests. Alternatively, use a high-strength threaded rod to avoid steel failure. conduct confined tests with an embedment of approximately ASTM A193 B7 is a readily available high-strength threaded 7da in accordance with 4.7.3.2 and with the value No,i in rod material. Heat-treatment may also be used to increase accordance with Eq. (4-2). the rod strength. In all cases, the thread configuration should be representative of the threaded rod types included No,i ≤ km fc, test, ihe1.f5 N (4-1) in the qualification of the adhesive anchor system. where km equals 10 for tests conducted in uncracked 4.7.2.1.1 An exception to this is in cases where use of concrete, and 7 for tests conducted in cracked concrete; No,i a high-strength steel anchor element is insufficient to prevent is the mean ultimate tension load as determined from uncon- steel failure (minimum strength equivalent to ASTM A193); the anchor embedment may be reduced accordingly. In cases fined tests, N; and fc,test,i is the concrete compressive where the embedment depth must be reduced to avoid failure strength in test series i, MPa. modes other than bond failure, check the effectiveness of the MPII by other means; with respect to hole cleaning and No,i = αsetupNo,i,confined N (4-2) injection at the unreduced maximum hole depth, also check by other means. The method described in 4.7.2.1.2 shall be where No,i,confined is the mean ultimate tension load permitted. measured in confined reference tests at hef ≈ 7da, N, and αsetup is the reduction factor for service-condition tests R4.7.2.1.1 Where it is not possible to preclude steel performed as confined tests in accordance with 10.4.5.1. failure for a specific embedment, it is permissible to reduce the bonded length to force a bond failure. When this step is R4.7.2.2 For sustained load tests, it is important that the taken, it is necessary to simulate the hole cleaning and sustained load is based on the maximum potential bond adhesive injection processes for the full-depth hole condition by strength on which the anchor design will be based. Many some other means. The use of stacked blocks is one such adhesive anchor systems exhibit concrete breakout failure method. when tested in tension at minimum embedment. In these cases, it is necessary to increase the embedment to a point 4.7.2.1.2 For cases where the embedment depth must where bond failure occurs. The establishment of bond failure be reduced to avoid failure modes other than bond failure, solely on the basis of physical observation of the failed the following test method shall be permitted for use to verify specimen, however, is problematic. Development of fracture the installation method. surfaces that do not project to the concrete surface may preclude the attainment of maximum potential bond Stack concrete blocks A and B, as shown in Fig. 4.3(a), as strength. Comparison of the mean strength obtained in the required to achieve the desired embedment and perform the tension tests with a predicted value for the concrete breakout drilling operation. Although the core drill is shown, other

22 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Fig. 4.3—Establishing bond strength at deeper embedments: optional method to verify installation. strength serves to determine whether that value is representative adhesive anchors, whereby the reaction force is transferred into of the maximum potential bond strength or reflects a the concrete in close proximity to the anchor element. The hole premature concrete breakout failure. For cases where the in the confining plate shall be 1.5do to 2.0do and the thickness resistance at the embedment required to promote bond shall be greater than or equal to da. Place a sheet of tetrafluoro- failure exceeds the strength of the high-strength rods used ethylene (TFE), polytetrafluoroethylene (PTFE), fluorinated for testing, confined tests may be performed and converted ethylene (FEP), or perfluoroalkoxy (PFA) of 0.5 ± 0.1 mm to unconfined values via the term α setup. corresponding to the area of the confining plate between the confining plate and concrete surface to reduce friction. 4.7.3 Unconfined and confined tension tests R4.7.3 This standard permits the use of confined testing 4.7.3.3 Confined tests are specified primarily to reduce for service-condition tests in cases where unconfined testing the size and quantity of concrete test members required. In no is either impractical or does not facilitate the assessment of case shall the results of confined tests be compared with the the characteristic bond stress for the product. Table R4.1 results of unconfined tests, for example, for the determination provides guidance for the conduct of specific tests in of α (10.4.3). accordance with ACI 355.4M. 4.8—Tests in cracked concrete 4.7.3.1 Conduct unconfined tension tests where specified. 4.8.1 Perform tests in concrete test members meeting the Figure 4.4 shows a typical unconfined tension test setup whereby the supports are spaced a suitable distance from the requirements of 4.3. Initiate cracking in the test member. anchor to permit unrestricted development of a conical Install the anchor according to 4.5 so that the axis of the concrete fracture surface. anchor is coincident with the crack plane. Install instrumentation for monitoring crack-opening width. Monitor crack-opening 4.7.3.2 Confined instead of unconfined tension tests may width using dial gauges or electronic transducers located be conducted where permitted (Table 3.1, 3.2, or 3.3). roughly symmetrically on either side of the anchor on an axis Figure 4.5 shows a typical confined tension test setup for

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 23 Table R4.1—Confined and unconfined testing* Suitability test Test configuration Reference test for establishing Reference test for residual capacity applied load† Sensitivity to crack width cycling Unconfined during crack cycling Unconfined Confined and confined for residual capacity Sensitivity to freezing/thawing conditions Confined unconfined Confined Sensitivity to sustained load Confined Unconfined Confined Seismic tension load cycling Unconfined or confined Unconfined or confined depending on NA configuration of test during load cycling Seismic tension residual capacity Unconfined or confined NA Unconfined or confined depending on configuration of residual capacity test *In no case are the results of confined tests compared with the results of unconfined tests. †All reference tests should be configured to result in bond failure. Fig. 4.4—Example of unconfined tension test setup for Fig. 4.5—Example of confined tension test setup for adhesive adhesive anchors. anchors. oriented perpendicular to the crack plane to permit interpolation 4.8.2 Subject the anchor to the specified loading sequence for the crack width at the anchor location. Keep the distance while monitoring the crack opening width at the surface as from the crack width measurement point to the anchor required in the specific test centerline as small as possible; not to exceed the greater of 1.0hef or 125 mm. Increase the crack width by the specified 4.8.3 Record the applied load, corresponding anchor crack value prior to applying external loads to the anchor. displacement, and crack width during the test as required in Verify by suitable means that the system used for crack the specific test. Use a sampling frequency appropriate for formation and the associated test procedures produce cracks the load or strain rate employed for the test. that remain parallel during the performance of tests. The crack width, as measured at the opposite face of the test 4.9—Changes to products member in line with the anchor location, or as estimated 4.9.1 Prior to modifying an anchor adhesive system based on the crack width measurement on each side of the test member as close to the opposite face as possible, should be previously assessed in accordance with ACI 355.4M, the approximately equal to the crack width measured on the manufacturer shall report the nature and significance of the anchor side. Verification that the test procedure used for a change in the system to the ITEA serving as the primary specific test will produce the appropriate crack geometry laboratory for the original assessment. The ITEA shall shall be performed at the beginning of the test series. determine which tests, if any, shall be performed to determine whether the change in the adhesive anchor system is equivalent R4.8.1 The test specimen geometry and loading method to the previously assessed adhesive anchor system. are determinants in whether the cracks remain parallel over the depth of the member. It is important that the crack width measurement devices reflect the crack width at the anchor location. It is generally acceptable to check the performance of the specimen at the beginning of the test series.

24 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY For all changes that might affect the anchor performance, as appropriate. The manufacturer shall select from the following the ITEA shall perform sufficient reference and reliability list a minimum of three fingerprint tests for this purpose: tests to assess the impact of the change. Test results shall be • Infrared absorption spectroscopy—ASTM E1252 shown statistically equivalent to those of the originally tested • Bond strength—ASTM C882/C882M or equivalent product. If the results of the reference and reliability tests cannot be shown to be statistically equivalent to the results method of the original testing, retest and evaluate the modified • Specific gravity—ASTM D1875 adhesive anchor system in accordance with ACI 355.4M. • Gel time—ASTM C881/C881M • Viscosity—ASTM D2556, ASTM F1080, or equivalent R4.9.1 Modifications to the adhesive anchor system that should trigger this provision include significant changes to method the MPII including, but not limited to, changes to scope of • Other tests that may be appropriate for the specific product use, hole cleaning methodology, injection technique, and listed cure times. Other changes include the adhesive that can be shown to provide positive identification formulation, adhesive confectioning, adhesive mixing and 5.3.2 Test methods not described herein shall be proposed to delivery system, and the supplementary tools and devices and accepted by the ITEA prior to commencing tests. Other test used to clean the drilled hole. methods shall be permitted if approved by the ITEA. CHAPTER 5—REQUIREMENTS FOR ANCHOR 5.4—Packaging IDENTIFICATION R5.4 The packaging of adhesive components in the adhe- 5.1—Basic requirements sive anchor system should contain the information required R5.1 The description of the adhesive anchor system should in 5.4 in a legible and readily-understandable format. be developed by the ITEA based on information provided by 5.4.1 Packaging of the adhesive materials shall include: the manufacturer. • Manufacturer’s name and address • Lot number 5.1.1 Provide the following information in the evaluation • Packing date and shelf life or product expiration date report. • MPII and application information 5.1.1.1 Product description, including: CHAPTER 6—REFERENCE TESTS • Generic or trade name. 6.1—Purpose • Anchor element dimensions; constituent materials; and R6.1 Reference tests form the basis for the adhesive appropriate physical properties including tensile anchor system when subjected to suboptimal conditions. As strength, hardness, and coatings. such, it is important that the concrete used for these tests is • A description of the adhesive components including the as closely related as possible to the concrete used for the adhesive name, packaging system, mixing ratios, gel suitability tests. Depending on the manner in which the time, cure time, storage information, and shelf life. reference tests are conducted, they may also serve as service-condition tests for the system (Chapter 8). 5.2—Verification R5.2 Additional testing as required to verify the components 6.1.1 Reference tests are performed in each batch of concrete to obtain baseline values for reliability and service-condition of the adhesive anchor system is at the discretion of the ITEA. tests where reference values are required to assess the effects of 5.2.1 The testing and evaluation agency shall verify the suboptimal hole cleaning, temperature variation, mixing effort, cracking, sustained load, installation direction, spacing, edge characteristics reported in accordance with 5.1.1.1 against distance, type of loading (shear or tension), environmental the manufacturer’s product specifications. exposure, and member thickness on anchor performance. 5.3—Fingerprinting adhesive materials 6.1.2 Unless otherwise noted, perform reference tests as R5.3 Fingerprinting the adhesive anchoring materials confined tension tests (4.7.3). involves the performance of specific tests to establish a R6.1.2 The use of confined tests is based on two baseline of the adhesive material for comparing future considerations: batches of product. If the adhesive material is changed by the manufacturer, that change may or may not significantly 1. Confined tests measure the bond strength of the affect the published performance of the anchor system. anchorage as opposed to the concrete capacity associated Selection of appropriate tests for comparison with future with concrete failure modes such as concrete cone batches is a critical function. The use of alternate tests to breakout. As such, they are suitable to assess the effects address other materials is at the discretion of the ITEA. The of temperature variation, suboptimal hole cleaning, fingerprinting tests may or may not be part of the manufac- mixing effort, sustained load, installation direction, turer’s quality control system. temperature variations, and environmental exposure on anchor performance. 5.3.1 Test the adhesive material components used for the qualification testing to establish a standard fingerprint for 2. Confined tests do not generate large spall cones, and as comparison with future production of adhesive material in such serve to reduce the volume of concrete required accordance with the required quality audits. It shall be for the test program. permitted to test the components separately or their mixture, 6.1.3 Reference tests shall be permitted to be performed as unconfined tension tests only if the service-condition tests

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 25 Fig. 6.1—Example test layout. CHAPTER 7—RELIABILITY TESTS 7.1—Purpose are also performed as unconfined tests. Where unconfined tension tests are used as reference tests, they shall be R7.1 Reliability tests are intended to check the sensitivity of compared to unconfined reliability or service-condition the adhesive anchor system to foreseeable variations from tests. In all cases, bond failure is required (refer to 4.7.3). optimal installation conditions. They are not pass-fail tests, but rather provide the necessary input for determining the charac- 6.2—Required tests teristic maximum bond stress for the adhesive anchor system. R6.2 The use of confined tests serves to reduce the volume 7.1.1. Reliability tests are performed to establish that the of concrete required for the tests, and may also be necessary anchor is capable of safe, effective behavior under normal to force bond failures for shallower embedments. Note the and adverse installation conditions. use of unconfined tests for reference tests can lead to an unconservative assessment if the unconfined reference tests 7.2—Required tests result in concrete cone failures. One example is under- R7.2 Required reliability tests are a function of the options representing the maximum bond strength of the adhesive anchor system. selected for the assessment, including uncracked or cracked concrete assessment, admissible exposure conditions, and 6.2.1 Required reference tests are given in Table 3.1 for required job-site quality control measures. anchors to be qualified for use in uncracked concrete only and in Table 3.2 or 3.3 for anchors to be qualified for use in 7.2.1 Required reliability tests are given in Table 3.1 for both uncracked and cracked concrete. adhesive anchors to be qualified for use in uncracked concrete only and in Table 3.2 or 3.3 for adhesive anchors to 6.2.2 Conduct reference tests in the same concrete batch be qualified for use in both uncracked and cracked concrete. used for the reliability or service-conditions tests to which they are compared. Reference tests may be used for comparison 7.2.2 Tests for the influence of drill tolerance on anchor with more than one series of reliability or service-condition behavior are not required. tests. Refer to Fig. 6.1 for an example test layout. 7.3—Conduct of tests 6.2.3 The anchor diameters for which reference tests are R7.3 Reliability tests should be conducted under ideal required shall correspond to requirements for the reliability or service-condition tests for which the reference tests are laboratory conditions to avoid under-representing the bond performed. strength characteristics of the adhesive anchor system. 6.2.4 Reference tests for the assessment of tests conducted 7.3.1 Prepare test members, install anchors, and test in in uncracked concrete shall be performed in uncracked accordance with Chapter 4 unless otherwise noted. concrete. Reference tests for the assessment of tests conducted in cracked concrete shall be performed in cracked concrete. 7.3.2 Perform tests in dry concrete except as required by specific tests. 6.2.5 It shall be permitted to perform additional reference tests (4.2.4). 7.3.3 Perform tests with air, concrete, and anchor at standard temperature unless otherwise noted. 6.3—Conduct of tests R6.3 Reference tests should be conducted under ideal 7.4—Reliability tests R7.4 Reliability tests are not intended to sanction or laboratory conditions to avoid under-representing the bond strength of the adhesive anchor system. otherwise imply acceptance of job-site variations from the MPII, nor do they ensure proper functioning under all 6.3.1 Prepare test members, install anchors, and test in possible and foreseeable job-site errors. While it is assumed accordance with Chapter 4. that the on-site installation personnel will generally conform to the MPII, the potential for inadvertent deviations from the 6.3.2 Perform tests listed in Chapter 3 under Reference MPII, particularly with respect to hole cleaning procedures, Tests in dry concrete. forms the basis for many of the reliability tests. 6.3.3 Perform tests listed in Chapter 3 under Reference Tests with air, concrete, and anchor at standard temperature.

26 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Gross installation errors as denoted in this section are not 7.5.2 General test conditions—Perform confined tension addressed by this standard and are assumed to be precluded tests in uncracked concrete. by attention to worker training and job-site inspection and quality control practices. 7.5.3 The test description provided herein presumes a method of hole cleaning that includes cleaning the hole wall 7.4.1 Reliability tests are intended to assess the sensitivity with a brush and blowing out the hole with air. Other of the tested system to variations in installation and service- cleaning methods are permitted; however, the MPII for the condition parameters that are likely experienced in practice. product shall contain sufficient specificity to permit the They are not intended to address gross installation errors. determination of a numeric (50 percent) reduction of hole Gross installation errors are characterized by significant cleaning effort. For hole cleaning methods involving deviations from the MPII or design specifications and brushing and blowing operations, such specificity shall include, but are not limited to: include as a minimum: • Deviations from the specified embedment depth • Use of a nominal diameter drill bit other than that specified 1. Requirements for all equipment to be used in the hole • Incorrect assembly or operation of the adhesive mixing cleaning process, including air/vacuum pressure, nozzle construction, and brush dimension and materials and dispensing equipment as applicable • Use of the product in base materials other than structural 2. Acceptable methods and minimum number and duration concrete of operations required for removal of drilling debris • Use of the product in concrete exhibiting compressive from hole strength outside of the specified range 3. Acceptable methods and minimum number and duration • Use of the product in base materials having a temperature of operations required for removal of dust or drilling flour from the hole wall outside of the specified range for the product • Violation of specified gel and cure times 4. The required sequence of operations • Violation of storage and shelf life restrictions for the An exception to determine the reduced hole cleaning effort, regardless of the number of hole cleaning operations adhesive specified in the MPII, the number of times the operation step is repeated in tests for reduced cleaning effort shall not 7.5—Sensitivity to hole cleaning—dry concrete exceed two. For the purposes of this section, an operation Refer to Table 3.1, Test 2a; Table 3.2, Test 2a; and Table 3.3, shall be considered to be an action that is repeated not more than three times in succession. Test 2a. 7.5.4 Drill the hole downward to the depth defined by the R7.5 Hole cleaning procedures can have a significant manufacturer. Clean the hole with 50 percent of the specified minimum number of operations in the specified sequence, influence on bond strength. This reliability test checks for the rounding down to the next whole number of operations. So sensitivity of anchor bond strength to suboptimal hole if a total of four brushing and four blowing operations are cleaning effort (50 percent) in dry concrete conditions. The specified, install the anchor with only two brushing and two MPII should provide necessary instructions for hole blowing operations. cleaning with the required degree of specificity to permit evaluation of the 50 percent hole cleaning effort. For 7.5.4.1 If the MPII does not contain sufficient specificity example, if the MPII calls for blowing out the hole twice with with respect to hole cleaning as defined in 7.5.3, to permit compressed air followed by four insertions of a brush and the determination of a numeric reduction of hole cleaning two additional applications of compressed air, 50 percent effort per this section, or if the required equipment is not effort would be assessed as one application of compressed specified as defined in 7.5.3, conduct the tests without hole air followed by two insertions of the brush and one application cleaning. Load the anchor to failure with continuous of compressed air. Where three repeats of a specific operation measurement of load and displacement. are specified, one should be performed; where one is specified, the cleaning step should be omitted. The type of 7.6—Sensitivity to hole cleaning—saturated brush, such as steel and nylon, and its diameter should be concrete specified in the MPII together with any other details, such as air pressure, that might affect the effectiveness of the hole- Refer to Table 3.1, Test 2b; Table 3.2, Test 2b; and Table 3.3, cleaning process. If the MPII does not contain sufficient Test 2b. information to permit the establishment of a cleaning effort that represents 50 percent of the specified effort, hole R7.6 Hole cleaning procedures appropriate for dry cleaning should be omitted. concrete may be inappropriate for a hole drilled into saturated concrete due to the presence of wet drilling mud. It is antic- An effective upper limit on repetitions of any single hole- ipated that the MPII will contain specific procedures, such cleaning operation of four is intended to prevent the speci- as flushing the hole with water, for cleaning holes drilled fication of excessive hole cleaning effort in the MPII as a into saturated concrete or where the drilled hole has been means of satisfying reliability test criteria. subjected to water prior to the anchor installation (for example, from rain). Due to the likelihood that products will 7.5.1 Purpose—These reliability tests are used to assess be installed in concrete exposed to water (such as concrete the sensitivity of the anchor tension capacity to the degree of exposed to weather), these tests are mandatory. hole cleaning employed prior to anchor installation.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 27 7.6.1 Purpose—These reliability tests are used to assess 7.8—Sensitivity to hole cleaning—submerged the sensitivity of the adhesive material to hole cleaning for concrete applications in water-saturated concrete. Refer to Table 3.1, Test 2d; Table 3.2, Test 2d; and Table 3.3, 7.6.2 General test conditions—Perform confined tension Test 2d. tests in uncracked concrete. R7.8 For installation of adhesive anchors in submerged 7.6.3 Qualification for use with carbide drill bits—Drill a concrete, specific instructions should be provided in the pilot hole downward to the specified hole depth with a bit MPII. These tests are optional; however, failure to assess approximately half the diameter of the specified hole diam- this condition will result in restrictions on the use of the eter. Fill the pilot hole with potable water and ensure that the adhesive anchor system. hole remains flooded for a minimum of 8 days or 192 hours. Immediately prior to installing the anchor, remove all free- 7.8.1 Purpose—These optional reliability tests are used to standing water with a vacuum and redrill the existing hole assess the sensitivity of the adhesive material to hole with the specified drill bit diameter. Clean the hole in accor- cleaning for applications in submerged concrete. dance with the reduced cleaning effort specified in 7.5.3 and 7.5.4. Install the anchor in accordance with the MPII. Load the 7.8.2 General test conditions—Perform confined tension anchor to failure with continuous measurement of load and tests in uncracked concrete. displacement. Other methods of achieving saturation of the concrete, such as immersing the test member, shall be 7.8.3 Cover the surface of the water-saturated concrete test permitted. If methods other than those described previously member with potable water to a minimum depth of 13 mm are used, it shall be shown by appropriate methods that the for the duration of the test, including anchor installation and concrete in the area of the anchorage is water saturated. tension testing. Drill the hole downward in the submerged concrete, clean the hole in accordance with the reduced 7.6.4 Qualification for water-flushed holes—Redrill the cleaning effort specified in 7.5.3 at 50 percent of the cleaning pilot hole with the specified drill bit. If the MPII specifies efforts given in the MPII for this application, and install the flushing of the hole with water prior to anchor installation, it anchor in accordance with the MPII. Load the anchor to failure shall be permitted to flush the hole with potable water prior with continuous measurement of load and displacement. to installing the anchors. Prepare the hole with reduced cleaning effort in accordance with 7.6.3. Immediately prior 7.9—Sensitivity to mixing effort to installing the anchors, remove freestanding water from the Refer to Table 3.1, Test 2e; Table 3.2, Test 2e; and Table 3.3, hole with a vacuum. Install the anchor in accordance with the MPII. Load the anchor to failure with continuous measurement Test 2e. of load and displacement. R7.9 For adhesive anchor systems that do not use automatic 7.7—Sensitivity to hole cleaning—water-filled hole metering and mixing systems, it is necessary to check the Refer to Table 3.1, Test 2c; Table 3.2, Test 2c; and Table 3.3, sensitivity of the system to suboptimal mixing of the adhesive components. Test 2c. R7.7 For installation of adhesive anchors in water-filled 7.9.1 Purpose—These reliability tests are used to assess the sensitivity of the adhesive material to mixing effort. holes, specific instructions should be provided in the MPII. These tests are required only for those anchor systems where These tests are optional; however, failure to assess this the mixing of the adhesive material is substantially condition will result in restrictions on the use of the adhesive controlled by the installer. Such cases include systems that anchor system. require components to be mixed until a color change is effected throughout the adhesive material, the adhesive 7.7.1 Purpose—These optional reliability tests are used to materials to be mixed with recommended equipment for a assess the sensitivity of the adhesive material to hole cleaning specific duration, and the adhesive materials be mixed with for applications in water-saturated concrete where the drilled a repetitive mixing operation a specific number of times. holes contain standing water at the time of anchor installation. 7.9.1.1 These tests are not required for capsule anchor 7.7.2 General test conditions—Perform confined tension systems or cartridge or bulk systems that employ automatic tests in uncracked concrete. metering and mixing through a manifold and disposable mixing nozzle. 7.7.3 Qualification for use with carbide drill bits— Prepare and clean the hole in accordance with 7.6.3; 7.9.2 General test conditions—Perform confined tension however, refill the hole with potable water immediately prior tests in uncracked concrete. to installing the anchor and install the anchor in the water- filled hole. Load the anchor to failure with continuous 7.9.3 Conduct tests as required to establish the required measurement of load and displacement. time for full mixing using standard mixing equipment. Reduced mixing effort shall be achieved by decreasing the 7.7.4 Qualification for water-flushed holes—Prepare and mixing time required for full mixing by 25 percent. Load the clean the hole in accordance with 7.6.4; however, refill the anchor to failure with continuous measurement of load and hole with potable water immediately prior to installing the displacement. anchor. Install the anchor in accordance with the MPII. Load the anchor to failure with continuous measurement of load 7.10—Sensitivity to installation in water-saturated and displacement. concrete Refer to Table 3.1, Test 2f; Table 3.2, Test 2f; and Table 3.3, Test 2f.

28 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY R7.10 For systems used only in conjunction with R7.13 The effect of upper-bound service-condition increased levels of job-site quality control (for example, cracking on the tension resistance of adhesive anchors in continuous inspection and proof loading), lower thresholds low-strength concrete is assessed with a crack width of 0.5 mm. are established for the reliability tests. It is therefore necessary to perform supplemental checks for the sensitivity of the 7.13.1 Purpose—These reliability tests are used to assess adhesive anchor system to installation in water-saturated the sensitivity of the anchor system installed in low-strength concrete where the full cleaning effort in accordance with concrete to a wide crack in the concrete passing through the the MPII is used. anchor location. 7.10.1 Purpose—These reliability tests are used to 7.13.2 General test conditions—Perform tension tests in independently assess the sensitivity of the adhesive material cracked concrete. Tests on adhesive anchors shall be to applications in water-saturated concrete where the anchor confined tension tests. category shall be determined in accordance with Table 10.6. 7.13.3 Initiate the crack in the test member and install the 7.10.2 General test conditions—Perform tests in accordance anchor at the crack location so that the axis of the anchor lies with 7.6; however, hole cleaning shall be conducted in approximately in the plane of the crack. Visually confirm the accordance with the MPII. correct location of the crack in the drilled hole prior to installing the anchor in accordance with 4.5.2. Open the 7.11—Sensitivity to installation in water-filled crack by the specified value Δw. Perform a confined tension hole—saturated concrete test to failure with continuous measurement of load, displacement, and crack width. Refer to Table 3.1, Test 2g; Table 3.2, Test 2g; and Table 3.3, Test 2g. 7.14—Sensitivity to crack width—high-strength concrete R7.11 For systems used only in conjunction with increased levels of job-site quality control (for example, continuous Refer to Table 3.2, Test 4. inspection and proof loading), lower thresholds are established for the reliability tests. It is therefore necessary to perform R7.14 The effect of upper-bound service-condition supplemental checks for the sensitivity of the adhesive anchor cracking on the tension resistance of adhesive anchors in system to installation in water-filled holes where the full high-strength concrete is assessed with a crack width of cleaning effort in accordance with the MPII is used. 0.5 mm. This corresponds to a tolerable crack width for inte- rior exposures. 7.11.1 Purpose—These optional reliability tests are used to independently assess the sensitivity of the adhesive material 7.14.1 Purpose—These reliability tests are used to assess to applications in water-filled hole in saturated concrete for the sensitivity of the anchor system installed in high-strength cases where the anchor category shall be determined in concrete to a wide crack in the concrete passing through the accordance with Table 10.6. anchor location. 7.11.2 General test conditions—Perform tests in accordance 7.14.2 General test conditions—Perform tension tests in with 7.7; however, hole cleaning shall be conducted in cracked concrete. Tests on adhesive anchors shall be accordance with the MPII. confined tension tests. 7.12—Sensitivity to installation in submerged 7.14.3 Initiate the crack in the test member and install the concrete anchor at the crack location so that the axis of the anchor lies approximately in the plane of the crack. Visually confirm the Refer to Table 3.1, Test 2h; Table 3.2, Test 2h; and Table 3.3, correct location of the crack in the drilled hole prior to Test 2h. installing the anchor in accordance with 4.5.2. Open the crack to the specified value Δw. Perform a confined tension R7.12 For systems used only in conjunction with test to failure with continuous measurement of load, increased levels of job-site quality control (for example, displacement, and crack width. continuous inspection and proof loading), lower thresholds are established for the reliability tests. It is therefore necessary 7.15—Sensitivity to crack width cycling to perform supplemental checks for the sensitivity of the Refer to Table 3.2, Test 5, and Table 3.3, Test 3. adhesive anchor system to installation in submerged concrete where the full cleaning effort in accordance with R7.15 The crack-width cycling test simulates the effect of the MPII is used. crack opening and closing as it might occur over the anchor service life due to diurnal temperature changes, settlement, 7.12.1 Purpose—These optional reliability tests are used or restraint of shrinkage and creep on the anchor tension to assess the sensitivity of the adhesive material to applications resistance. The test consists of three parts: in submerged concrete where the anchor category shall be determined in accordance with Table 10.6. 1. Installation of the anchor in the crack and application of the static sustained load to the anchor. 7.12.2 General test conditions—Perform tests in accordance with 7.8; however, hole cleaning shall be conducted in 2. Cycling of the crack width and monitoring of the accordance with the MPII. anchor displacement. 7.13—Sensitivity to crack width—low-strength 3. Performance of a tension test to failure to measure the concrete residual tension resistance of the tested anchor. Refer to Table 3.2, Test 3.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 29 7.15.1 Purpose—These reliability tests are performed to Fig. 7.1—Crack-width requirements for crack cycling. evaluate the performance of anchors located in cracks whose width is cycled. during the crack cycling portion of the test. The crack opening width Δw2 shall be permitted to increase (Fig. 7.1); 7.15.2 General test conditions— Perform crack cycling however, the difference Δw1 – Δw2 shall be not less than tests as unconfined tension tests in cracked concrete. Tests 0.1 mm for the duration of the crack cycling portion of the for residual capacity following crack cycling are confined test. During the test, adjust the amplitude of the load applied tension tests performed in cracked concrete. to the test member as required to maintain a minimum differential Δw1 – Δw2 of 0.1 mm. This may result in an 7.15.3 Prior to installing anchors in the test member, it increase in the crack width Δw1 beyond 0.3 mm for part of shall be permitted to run opening and closing cycles as the crack cycling portion of the test. required to stabilize the relationship between crack width and applied load. Loading shall not exceed the elastic limit R7.15.3 The crack width is dependent, in part, on the bond of the test member reinforcement. With the test member stress developed by the embedded reinforcement on each unloaded, install the anchor in a closed (hairline) crack that side of the crack. Running opening and closing cycles serves is sufficiently planar to ensure that the crack will approximately to stabilize the bond stresses at a constant level and permits bisect the anchor location over the extent of the anchor load- control of the crack width via application of a defined external transfer zone. Visually verify the positioning of the anchor in load. Equation (7-1) provides a load level Nw on the anchor the crack in accordance with 4.5.2.2. Measure the crack that is consistent with the load on headed anchors corre- width in accordance with 4.8. After installation of the anchor sponding to the threshold displacements established for this but before the anchor is loaded, subject the test member to test. Where these threshold displacements are exceeded in the loading as required to open the crack width by Δw1 = 0.3 mm, test, the load Nw is reduced to a level that does not generate where Δw1 is additive to the initial width of the crack after displacements in excess of the threshold values. Crack closing installation of the anchor but before loading of the anchor. is accomplished with the embedded reinforcement and may be Following application of load to the anchor sufficient to influenced by slippage of the anchor in the crack. It is not remove any slack in the loading mechanism, begin recording intended that crack closure should be controlled externally, for the anchor displacement, and increase the tension load on the example, with a hydraulic cylinder. anchor to Nw as given by Eq. (7-1). Apply the load in accordance with 4.7.2.2, unconfined. 7.15.3.1 Measure the load-displacement relationship up to load Nw. At load Nw, measure the displacements of the  f--c-f-,c--t,--et--es--ts-,-t-2- n anchor and the crack-opening widths Δw1 and Δw2, either  continuously or at least after 1, 2, 5, 10, 20, 50, 100, 200, Nw = 0.3 Nk, i N (7-1) 500, and 1000 cycles of crack opening and closing. where 7.15.4 Following completion of the crack cycling portion of the test, unload the anchor, record the anchor displacement, Nk,i = an anchor assessed in accordance with Table 3.2— open the crack width to Δw = 0.3 mm and perform a tension characteristic resistance as determined from test of the anchor to failure with continuous measurement of load and displacement. reference service-condition tests in low-strength 7.16—Sensitivity to freezing and thawing cracked concrete per Table 3.2, Test 11c, N; Refer to Table 3.1, Test 3; Table 3.2, Test 6; and Table 3.3, = an anchor assessed in accordance with Table 3.3— Test 4. 25 percent of the characteristic resistance from R7.16 The test for sensitivity to freezing and thawing is intended to simulate in-service temperature fluctuations that reference service-condition tests in low-strength the anchor might be subjected to during its service life. uncracked concrete per Table 3.3, Test 8a, N; 7.16.1 Purpose—These reliability tests are performed to evaluate the performance of anchors under freezing-and- fc,test = concrete compressive strength as measured at the thawing conditions. time of testing, MPa; fc,test,2 = concrete compressive strength corresponding to the tests used to establish Nk,i, MPa; and n = normalization exponent determined in accordance with 10.2. While maintaining the static load on the anchor within 5 percent of Nw, cyclically load the test member as required to cause the crack width to alternate continuously between Δw1 (0.3 mm) and the lower crack width limit Δw2 (0.1 mm), where Δw2 is additive to the initial width of the crack as measured after installation of the anchor but prior to loading of the anchor. Open and close the crack 1000 times at a maximum frequency of approximately 0.2 Hz. During crack cycling, adjustment of the force required to maintain the crack opening width Δw1 constant shall be permitted. Hold the minimum load applied to the test member constant

30 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 7.16.2 General test conditions—Perform sustained 7.17—Sensitivity to sustained loading at standard tension tests in uncracked concrete followed by confined and maximum long-term temperature tension tests to failure. Refer to Table 3.1, Test 4; Table 3.2, Test 7; and Table 3.3, 7.16.3 The test member shall consist of a cube or cylinder Test 5. with side length (or diameter) of 200 mm ≤ lside ≤ 300 mm for anchor diameters M12 to M16. For anchor diameters greater R7.17 The sustained load, or creep test, is conducted to than 16 mm, the test member shall have a side length 15d ≤ lside establish the creep behavior of the adhesive anchor system ≤ 25d. Dimensions of the test member shall be chosen to over its service life. Tests are performed at standard tempera- avoid splitting the test member during the test conduct. ture of 23°C ± 4°C, and at long-term elevated temperature. Freezing-and-thawing-resistant concrete shall be permitted. The long-term elevated temperature corresponds to the Restraint of the test member as required to prevent splitting temperature category as per Table 8.1. shall be permitted. Where such restraint is used (for example, steel cylinder), dimensions of the specimen may be reduced. 7.17.1 Purpose—These reliability tests are performed to evaluate the performance of anchors under sustained loads at 7.16.3.1 Install and cure anchors at standard temperature. standard temperature and maximum long-term temperature. 7.16.3.2 Cover the top surface of the test member within 7.17.2 General test conditions a minimum 75 mm radius from the center of the test anchor, with potable water maintaining a minimum of 13 mm depth 7.17.2.1 Perform sustained tension tests in uncracked throughout the test. Seal all other exposed surfaces to concrete, followed by confined tension tests to failure. prevent evaporation of water. Load the anchor with a constant tension load Nsust,ft given by Eq. (7-2), to be 7.17.2.2 Install and cure anchors at standard temperature. maintained throughout the test. 7.17.2.3 Conduct tests at standard and long-term test  -f-fc--c,--,t--et-e-s--st-,-t-i n temperatures corresponding to the desired temperature categories  in accordance with Table 8.1. If tests at the long-term test Nsust, ft = 0.55N o,i N (7-2) temperature are performed with Nsust in accordance with Eq. (7-3), unreduced by the factor αlt and extrapolated to where 50 years, and compared to the limiting displacement at loss of No,i = mean tension capacity as determined from reference adhesion derived from tests at standard temperature, the tests at standard temperature are permitted to be omitted (10.11.3). service-condition tests in high-strength concrete as follows: Table 3.1, Test 7b; Table 3.2, Test 11b; or 7.17.2.4 Temperature control shall be maintained via ther- Table 3.3, Test 8b whereby results that are less than mocouples in the concrete test member. Embed thermocouples 85 percent of the mean value shall be excluded a maximum of 115 mm from the surface of the concrete into from the determination of the mean (for example, which the anchors are to be installed. Distance from the outer the mean shall be recalculated with the remaining perimeter of the installed anchor and thermocouple shall not results, N) (refer also to 4.7.2.2); exceed 10 mm. The thermocouples shall be either cast in the concrete or positioned in holes drilled in the cured test member. fc,test = concrete compressive strength as measured at the Drilled holes for thermocouples shall have a maximum nominal time of testing, MPa; diameter of 13 mm and shall be sealed in such a manner that the temperature readings reflect the concrete temperature. fc,test,i = concrete compressive strength corresponding to the tests used to establish No,i, MPa; and The exception to this is that thermocouples are not required if it can be experimentally demonstrated that the n = normalization exponent determined in accordance test procedure will consistently produce test member with 10.2. temperatures in accordance with the target temperatures. The test procedure will include monitoring of test chamber 7.16.3.3 Carry out 50 freezing-and-thawing cycles. temperature at maximum 1-hour intervals. 1. Maintain load at Nsust,ft throughout the freezing-and- 7.17.2.5 Each test shall have a minimum duration of thawing test. 42 days. 2. Raise the temperature of the chamber within 1 hour to 7.17.3 Tests at standard temperature 20°C ± 2°C. 7.17.3.1 After the curing period has elapsed, apply a 3. Maintain the chamber temperature at 20°C ± 2°C for an tension preload to the anchor prior to zeroing displacement additional 7 hours. readings not to exceed 5 percent of Nsust,lt or 1300 N, then increase the load on the anchor to a constant tension load 4. Lower the temperature of the chamber to –20°C ± 2°C Nsust,lt as given by Eq. (7-3). The load shall be applied using within 2 hours. an unconfined test setup as shown in 4.4 or a confined test setup as shown in Fig. 4.5. After the load has been applied, 5. Maintain the chamber temperature at –20°C ± 2°C for adjust the temperature of the test member until the temperature, an additional 14 hours. as recorded by the embedded thermocouples, is stabilized at the target temperature. 7.16.3.4 Measure the displacements during the temperature cycles.  -f-fc--c,--,t--et-e-s--st-,-t-i n i 7.16.3.5 If the test is interrupted, the samples shall always Nsust, lt = 0.55 No, N (7-3) be stored at a temperature of –20°C ± 2°C between cycles. 7.16.3.6 After the completion of 50 cycles, conduct a confined tension test to failure at standard temperature.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 31 where Nsust,lt or 1300 N to the anchor prior to zeroing displacement No,i = mean tension capacity as determined from refer- readings. Then increase the load on the anchor to a constant tension load Nsust,lt as given by Eq. (7-3) multiplied by αlt as ence service-condition tests in low-strength determined in accordance with Eq. (10-26). concrete as follows: Table 3.1, Test 7a; Table 3.2, Test 11a; or Table 3.3, Test 8a whereby results 7.17.4.3 Maintain load Nsust,lt and maintain temperature that are less than 85 percent of the mean value at the maximum long-term test temperature. For the shall be excluded from the determination of the frequency of displacement monitoring, refer to 7.17.3. At the mean, that is, the mean shall be recalculated with long-term test temperature, the temperature in the test the remaining results, N (refer also to 4.7.2.2); chamber may vary by ±3°C due to day/night and seasonal fc,test = concrete compressive strength as measured at the effects, but the required test chamber temperature shall be time of testing, MPa; achieved as an average over the test period. fc,test,i = concrete compressive strength corresponding to the tests used to establish No,i, MPa; and 7.17.4.4 To check the remaining load capacity after the n = normalization exponent determined in accordance sustained load test, unload the anchor and carry out a confined with 10.2. tension test at the maximum long-term test temperature. 7.17.3.2 Maintain the load at Nsust,lt and maintain the temperature at the target temperature. 7.18—Sensitivity to installation direction 7.17.3.3 Record anchor displacement for the test duration. Refer to Table 3.1, Test 5; Table 3.2, Test 8; and Table 3.3, The frequency of monitoring displacements shall be chosen to demonstrate the anchor characteristics. As displacements Test 6. are greatest in the early stages, monitoring frequency should R7.18 The majority of ACI 355.4M tests are performed on be high initially, but reduced over time. As an example, the following monitoring schedule would be acceptable: anchors installed in the downward position. Where anchors a) During the first hour—every 10 minutes are to be installed in other orientations, such as horizontal and b) During the next 6 hours—every hour overhead, tests are required to validate the performance of the c) During the next 10 days—every day adhesive anchor system for these orientations. These tests are d) Thereafter—every 5 to 10 days intended to ensure the MPII is adequate to describe the neces- 7.17.3.4 Temperatures in the test chamber may vary by sary installation steps, the adhesive anchor system is appro- ±6°C due to day/night and seasonal effects, but the required priate for installation in the tested orientation, and the bond test chamber temperature shall be achieved as an average strength has been correctly assessed for anchors installed in over the test period. Record the concrete test member the tested orientation. Factors of particular importance in the temperature at maximum 1-hour intervals. If thermocouples assessment include completely filling the hole with adhesive, are not used in accordance with 7.17.2.4, record the tempera- avoiding excessive adhesive run-out during the installation ture in the test chamber at maximum 1-hour intervals. process, and preventing anchor element sag during adhesive 7.17.3.5 Alternatively, the concrete test member cure. Because of the possibility for run-out of adhesive during temperature shall be recorded at maximum 24-hour intervals overhead installations, particular care should be exercised to provided the temperature of the conditioning chamber prevent skin or eye exposure, and all precautions indicated by necessary to maintain the target test member temperature is the MSDS for the product should be exercised. recorded at maximum 1-hour intervals. 7.17.3.6 If the concrete test member temperature falls For adhesive anchor systems not designed for other than below the minimum target temperature, including tolerances, down-hole installation, these tests may be omitted. To avoid for more than 24 hours, extend the test duration by the length accidental misuse of such products, however, it is necessary of time the temperature was below the target minimum. to provide a standardized warning label on the product (for 7.17.3.7 At the conclusion of the sustained loading example, cartridge and foil pack) and on the packaging portion of the test, conduct a confined tension test to failure indicating restrictions on use (Fig. 7.2). at standard temperature with continuous measurement of load and displacement. 7.18.1 Purpose—These optional reliability tests are 7.17.4 Tests at long-term elevated temperature performed to evaluate the performance of adhesive anchors 7.17.4.1 It is required to perform the tests in a concrete test installed horizontally and overhead, that is, vertically up. member made from the same concrete batch as the test member used for the tests at elevated short-term temperature. 7.18.2 General test conditions—Perform confined tension 7.17.4.2 After the curing period has elapsed, increase the tests in uncracked concrete. Conduct tests on all-thread temperature of the test member until the temperature, as anchors that have been installed in accordance with the MPII. recorded by the embedded thermocouples, is stabilized at the target temperature. Raise the temperature of the test chamber 7.18.3 Perform separate test series with anchors installed to the maximum long-term test temperature (either Category A horizontally and overhead. Perform tension tests to failure or B according to Table 8.1) at a rate of approximately 20°C with continuous measurement of load and displacement. per hour. Apply a tension preload not exceeding 5 percent of Install and cure anchors at the minimum and maximum installation temperatures for concrete and adhesive included in the MPII for downhole installation. Perform tension tests at standard temperature. 7.18.3.1 Anchor installation used for testing shall be reviewed for effectiveness. A procedure for verifying the effectiveness of overhead installation procedures using blind injection into a clear tube of equivalent diameter and length is

32 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Fig. 7.2—Required labeling for products not tested for sensitivity to installation orientation. Fig. 7.3—Procedure to verify effectiveness of adhesive Fig. 7.4—Torque test setup. injection method. 7.19.3 Apply increasing torque and record the torque and shown in Fig. 7.3. The procedure used shall enable the corresponding induced tension in the anchor bolt. The evaluation of the installation procedure as described in 10.12. washer shall not turn during the application of torque. 7.19—Torque test CHAPTER 8—SERVICE-CONDITION TESTS Refer to Table 3.1, Test 6; Table 3.2, Test 9; and Table 3.3, 8.1—Purpose Test 7. The purpose of the service-condition tests is to determine R7.19 Torque tests establish a tightening torque that the basic data required to predict the performance of the anchor under service conditions. produces a clamping force to be applied to the connection through the adhesive anchor, but not too high of a clamping R8.1 Service-condition tests establish the general strength force so that the bond between the adhesive and concrete or data for the anchor system in uncracked and cracked concrete between the anchor rod and the adhesive is broken. For and under various temperature and environmental exposure anchor elements that do not require the application of conditions, as well as in conjunction with seismic loading. torque, such as deformed reinforcing bar dowels, these tests may be omitted. 8.2—Required tests Required service-condition tests are given in Table 3.1 for 7.19.1 Purpose—These reliability tests are used to establish the maximum level of torque that can be applied to the adhesive anchors qualified for use in uncracked concrete installed anchor without inducing tension yield of the anchor only and in Table 3.2 or 3.3 for adhesive anchors qualified element or damaging the adhesive bond. for use in both uncracked and cracked concrete. Test require- ments for adhesive anchors assessed to resist seismic loads 7.19.2 General test conditions—Figure 7.4 shows the test are defined in Table 3.2. setup. The fixture shall contain all elements shown. The double-sided abrasive paper shall have sufficient roughness R8.2 Anchors to be qualified for use in cracked concrete to prevent rotation of the washer relative to the test fixture are installed in hairline cracks, which are then opened to a during the application of torque. Other methods of preventing crack width w of 0.3 mm before anchor loading. This crack rotation of the washer shall be permitted, provided it can be width is consistent with the expected response of rein- shown they do not affect the anchor performance. forced concrete structures under sustained load. 8.3—Conduct of tests R8.3 Service-condition tests are to be performed on anchors installed in accordance with the MPII. 8.3.1 Prepare test members, install anchors, and test in accordance with Chapter 4 unless otherwise noted. 8.3.2 Perform tests in dry concrete. 8.3.3 Perform tests with air, concrete, and anchor at standard temperature unless otherwise noted. 8.4—Tension tests in uncracked and cracked concrete Refer to Table 3.1, Tests 7a and 7b; Table 3.2, Tests 11a, 11b, 11c, and 11d; and Table 3.3, Tests 8a and 8b. R8.4 Tests are conducted in low- and high-strength concrete to establish the characteristic limiting bond stress.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 33 Depending on the characteristics of the adhesive and the Table 8.1—Required temperatures for embedment depths for which the system is to be assessed, it testing at long- and short-term elevated may be necessary to take special measures to achieve bond concrete temperatures* failures in these tests (refer to 4.7). The use of confined tests is permitted under certain conditions and can enable the use Temperature Long-term temperature, Short-term temperature, of reference tests for establishing characteristic limiting Tlt, °C Tst, °C bond stress values. category 8.4.1 Purpose—These tests are used to establish the bond A 43 80 resistance of the anchor system. B ≥ 43 ≥ Tlt + 11 8.4.2 Conduct of tests—Perform unconfined service- condition tension tests in accordance with Section 4.7 in both *All test temperatures have a minus tolerance of 0 degrees. low- and high-strength concrete. internal temperature by separate investigations and control 8.4.2.1 It shall be permitted to perform the service- the chamber temperature for the elevated temperature tests. condition tension tests described in Table 3.1, Tests 7a and 7b; Table 3.2, Tests 11a through 11d; and Table 3.3, Tests 8a 8.5.2.3 Qualify anchors for one or both of the temperature and 8b as confined tests if the evaluation for τk,cr is categories given in Table 8.1. Install and test a minimum of performed in accordance with 10.4.5.3.3. five anchors at each temperature data point. For Temperature Category A, perform tests at the short- and long-term test 8.5—Tension tests at elevated temperature temperatures. For Temperature Category B, perform tests on Refer to Table 3.1, Test 8a; Table 3.2, Test 12a; and anchors—at standard temperature, at the long-term and short-term test temperatures, and at a minimum of two Table 3.3, Test 9a. intermediate temperatures between the long-term and short- term temperatures with a maximum increment of 20°C. If the R8.5 Tension tests establish the anchor performance at difference between the standard temperature and the selected concrete temperatures elevated above standard temperature short-term test temperature is less than 20°C, then testing at for long and short durations (2.2—elevated concrete intermediate temperatures is not required. temperature). Temperature Category A provides a standard approach that assumes a potential long-term elevated 8.5.2.4 Install and cure all anchors at standard temperature. temperature consistent with hot climate exposures and a Following the recommended cure period, heat and maintain short-term temperature reflective of diurnal cycling in such the test members at the desired temperature for a minimum climates for a given sun exposure duration and concrete of 24 hours. Remove each test member from the heating mass. Typical sources of elevated concrete temperature are chamber and conduct a confined tension test to failure with anticipated, with the exception of heat of hydration in early- continuous measurement of load and displacement before age concrete, extreme elevated temperature (for example, the temperature of the test member falls below the temperature boiler rooms), and exposure to nuclear radiation in contain- listed in Table 8.1. ment structure. Temperature Category B establishes the same long-term temperature as temperature Category A. 8.6—Tension tests with decreased installation This temperature is relevant for testing to establish response temperature to sustained load. The short-term temperature remains open- ended, however, and the response of the adhesive anchor to Refer to Table 3.1, Test 8b; Table 3.2, Test 12b; and intermediate levels of elevated concrete temperature is Table 3.3, Test 9b. established. Products may be tested and assessed for either or both categories under this standard. R8.6 These tests establish the suitability of the adhesive anchor system for installation in concrete at lower-than- 8.5.1 Purpose—These service-condition tests are used to standard temperatures. All adhesive anchor systems qualified assess the sensitivity of the adhesive material to applications for installation in concrete temperatures below 10°C are in concrete with elevated temperatures that can occur over required to be installed and tested at the target concrete short periods of time, that is, short-term test temperatures, as temperature. When the target temperature for the system to well as elevated temperatures that may occur over more be qualified falls below 5°C, additional tests are required to extended periods, that is, long-term test temperatures. assess the effect of rising concrete temperatures on the anchor response. The rate of temperature rise is intended to 8.5.2 General test conditions—Conduct static tension be consistent with sun exposure. tests at long-term and short-term concrete temperatures corresponding to the desired temperature category (Table 8.1). Follow special procedures where the MPII includes them It shall be permitted to obtain qualification at multiple for low-temperature installation conditions. Where preheating temperature categories. of adhesive cartridges to reduce viscosity and facilitate adhesive flow is specified in the MPII, observations should 8.5.2.1 Conduct confined tension tests in uncracked be made to determine whether this results in retarded cure, concrete. lowering of the glass-transition temperature, and impaired resistance to creep. 8.5.2.2 Maintain temperature control with thermocouples in accordance with 7.17.2.4. Alternatively, it shall be permitted 8.6.1 Purpose—These service-condition tests are used to to correlate the chamber temperature with the test member assess the sensitivity of adhesive material to installation in concrete below the standard temperature. 8.6.2 General test conditions—Perform confined tension tests in uncracked concrete for anchors to be installed in

34 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY concrete having a temperature less than 10°C. Prior to residual bond strength in the punch test apparatus, provides installation, condition the anchor rod and test member to for a relatively uniform and conservative assessment of the the lowest installation temperature and maintain it for a exposure condition by assuring the entire bond layer is minimum of 24 hours. Install anchors in concrete test subjected to the aggressive compound. Care must be taken in members and allow them to cure at the stabilized tempera- preparation of the slices and punch testing to ensure reliable ture according to the MPII. Remove the test member from results. An austenitic stainless steel anchor element of the cooling chamber and tension test the anchors immedi- sufficient resistance should be used in the sulfur dioxide tests ately to assure the test members reasonably remains at the to avoid steel failure. It does not capture all possible environ- conditioned temperature. A thermocouple inserted into the mental exposures deleterious to anchor performance. The test member may be used to confirm the temperature at the two exposure conditions—alkalinity and sulfur—are time of testing. considered two of the most common and aggressive and, therefore, used as the baseline classification of anchor use. 8.6.2.1 When the adhesives are recommended for installation in concrete temperatures below 5°C in addition to 8.8.1 Purpose—These service-condition tests are used to the tests described in 8.6.2, perform the following test: assess the response of the adhesive material to attack by environmental aggressors. Verify the durability of the adhe- a) Install and test a minimum of five anchors per the MPII. sive material with slice tests. With slice tests, the sensitivity Prior to installation, condition the anchor rod and test of installed anchors to different environmental exposures member to the target temperature and maintain that can be assessed. The test for exposure to high alkalinity temperature for a minimum of 24 hours. (8.8.2.2.1) is required. The test for exposure to sulfur dioxide (8.2.2.2.2) is optional. b) Install the anchors in accordance with the MPII and allow them to cure at the stabilized target temperature 8.8.2 General test conditions—Conduct tests on 13 mm recommended by the MPII. diameter all-thread anchors or the smallest nominal diameter if it is larger than 13 mm. Embed anchors in cylindrical c) Apply a constant tension load Nsust,ft as given by Eq. (7-2). concrete test members having a minimum diameter of 150 mm. Raise the temperature of the test chamber at a constant rate Cast the concrete test members in lengths of steel or plastic to standard temperature for 72 to 96 hours while monitoring pipe having a wall thickness as required to prevent slice the displacement response for each anchor. A thermocouple splitting during punch testing. All test members shall originate inserted into the test member may be used to confirm test from the same concrete batch. Install anchors along the central member temperatures during the test. axis of the concrete test members according to the MPII. For Once the test member attains standard temperature, tests in sulfur dioxide, fabricate the anchor element from conduct a confined tension test to failure with continuous austenitic stainless steel. After curing the adhesive, concrete measurement of load and displacement. cylinders in which the anchors are installed shall be sawn with a diamond saw into 30 mm ± 3 mm thick slices so the resulting 8.7—Establishment of cure time at standard slices are undamaged. Slices shall be oriented perpendicular to temperature the anchor axis and consist of the concrete, adhesive material, and anchor element. Discard the top and bottom slices. Refer to Table 3.1, Test 8c; Table 3.2, Test 12c; and Prepare a minimum of 10 slices for each environmental Table 3.3, Test 9c. exposure to be investigated and 10 reference slices subjected to standard climate conditions. R8.7 Cure time of most adhesive compounds is inversely proportional to temperature. Where cure times are provided 8.8.2.1 Storage of reference slices—Store the slices for temperature ranges that overlap the standard temperature under normal climate conditions (dry/standard tempera- range, a temperature should be selected that corresponds to ture/relative humidity 50 ± 5%) for 2000 hours. the lower end of the range. 8.8.2.2 Storage of slices under aggressive environmental 8.7.1 Purpose—These service-condition tests are used to exposure—Store 10 slices each under the following environ- establish the minimum curing time of the adhesive material mental exposures. for the anchor to achieve full tension capacity. 8.8.2.2.1 High alkalinity— Store slices under standard 8.7.2 General test conditions—Perform confined tension climate conditions in a container filled with an alkaline fluid tests in uncracked concrete. Tests are conducted on anchors (pH = 13.2). All slices shall be completely covered for installed in accordance with the MPII at standard temperature. 2000 hours. Produce the alkaline fluid by mixing water with The anchors are allowed to cure for the minimum curing potassium hydroxide (KOH) powder or tablets until the pH time. Tests are also conducted on anchors installed in the value of 13.2 is reached. Maintain a mean alkalinity value of same way and allowed to cure for the time specified in the pH = 13.2 ± 0.2 during storage. If the measured alkalinity MPII plus an additional 24 hours. falls below 13.0, extend the test duration by the total length of time during which the pH value was less than 13.0. The 8.8—Durability assessment length of time the pH was less than 13.0 shall not be included Refer to Table 3.1, Tests 9a and 9b; Table 3.2, Tests 13a in the calculation of the mean alkalinity value. Monitor the pH value on a daily basis. and 13b; and Table 3.3, Tests 10a and 10b. R8.8 Durability tests are intended to assess the response of the adhesive to aggressive exposure conditions. The slice test, where a thin slice of the installed anchor is exposed to a specific environmental condition and then tested for

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 35 8.8.2.2.2 Sulfur dioxide—Perform tests according to EN Fig. 8.1—Punch test. ISO 6988 (Kesternich Test); the theoretical sulfur dioxide concentration, however, shall be 0.67 percent at the beginning of a cycle, corresponding to 2 dm3 of SO2 for a test chamber volume of 300 dm3. Perform at least 80 cycles. 8.8.3 Punch tests—Within 24 hours after removal of the specimen from storage, measure the thickness of the slices and test them in a test apparatus that permits the metal, that is, the anchor element part of the slice, to be punched through the slice while restraining the surrounding concrete (Fig. 8.1). The loading punch shall act centrally on the metal element. The peak load for each test shall be recorded. Discard results from slices that split during the punch test. Evaluate the bond stress τdur,i for each punch test using Eq. (8-1). τdur, i = -π---Nd---a-u--h,--i-s--l MPa (8-1) where hsl = measured thickness of slice i, mm; da = anchor diameter, mm; and Nu,i = measured axial load corresponding to failure of slice i, N. R8.8.3 Slices removed from storage should be tested as soon as possible to avoid the potential effects of specimen drying on the measured bond strength. 8.9—Verification of full concrete capacity Fig. 8.2—Corner test. in a corner R8.10 Tests are performed with two anchors installed Refer to Table 3.1, Test 10; Table 3.2, Test 14; and Table 3.3, parallel to an edge with the minimum edge and spacing Test 11. distances and in a test member having the smallest thickness for which the manufacturer wishes to qualify the anchor. R8.9 The concrete capacity design method assumes that Minimum values for edge distance and anchor spacing are maximum concrete breakout or bond capacity is reached at given in ACI 318M, Appendix D. These tests permit the selec- edge distances equal to or greater than cac. To check this tion of product-specific values for cmin and smin that, in assumption for a specific anchor system, tests are performed conjunction with some value of hmin, will allow anchor with single anchors in a corner with ca1 = ca2 = cac. This installation without damage in the form of splitting cracks to edge distance represents the critical edge distance at which the concrete. There can be more than one combination of there is no edge influence on the tensile capacity of the anchor these three minimum values. While the application of torque is as governed by concrete failure. The tests are performed in not required to set normal adhesive anchor systems, most concrete members having the smallest thickness hmin for MPIIs specify a maximum torque value for the clamp attach- which the manufacturer wishes to qualify the anchor. These ment to the concrete. Use of an elevated torque value (1.7Tinst) tests permit the selection of product-specific values for cac is intended to compensate for possible inaccuracies in torque that, in conjunction with some value of hmin, will allow wrenches on site. For conditions in which torque is not applied anchor installation without damage in the form of splitting to the anchor, the minimum edge distance is governed by the cracks to the concrete. There can be more than one drilling process used to install the adhesive anchor. combination of these values. 8.10.1 Purpose—This test is performed to verify for the 8.9.1 Purpose—This test is performed to determine the smin and cmin requested by the manufacturer that the concrete critical edge distance cac in test members with the minimum will not experience splitting failure during installation and specified thickness for that anchor. the required tension capacity is achieved. 8.9.2 General test conditions—Perform tests on single anchors in uncracked, low-strength concrete at a corner with equal edge distances of cac, and test member thickness hmin (Fig. 8.2). 8.10—Determination of minimum spacing and edge distance to preclude splitting Refer to Table 3.1, Test 11; Table 3.2, Test 15; and Table 3.3, Test 12.

36 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 8.10.2 General test conditions; test anchors in uncracked, 1. Test anchor elements having a cross-sectional area that low-strength concrete—Install two anchors at the minimum is less than a threaded bolt of the same nominal diam- spacing smin and the minimum edge distance cmin in test eter as the anchor within five anchor diameters of the members with the minimum thickness hmin to be reported for shear failure plane. the anchor. Place the two anchors in a line parallel to the edge of a concrete test element at a distance of at least 3hef 2. Test anchors at hef = hef, min and at hef = 2hef, min for from other groups. Select smin, cmin, and hmin depending on anchor diameters that exhibit pullout failure in uncon- anchor characteristics. fined tension tests at hef = hef, min where hef, min ≤ 8da. 8.10.2.1 Separate bearing plates shall be permitted to be 8.11.3 For anchors evaluated according to Table 3.2, at the used for each anchor to simplify the detection of concrete manufacturer’s option, shear tests shall be performed in cracking. The distance to the edge of the bearing plate from cracked concrete with a crack width of 0.3 mm, with the the centerline of the corresponding anchor shall be three shear load applied parallel to the crack. times the diameter da of the anchor being tested. 8.12—Simulated seismic tension tests 8.10.2.2 Calculate the expected mean tension failure Refer to Table 3.2, Test 17. load corresponding to the edge distance and spacing of the anchor group to be tested considering the service-condition R8.12 Simulated seismic tests are intended to assess the tests and effects of reduced spacing and edge distance. If the anchor performance in cracked concrete conditions under average prestressing force corresponding to 1.7Tinst exceeds cyclic loading. The crack width is assumed to be roughly the calculated mean tension failure load of the anchor group 150 percent of the maximum crack width associated with in uncracked concrete, perform a torque test in accordance elastic conditions, with the maximum level of cyclic loading with 8.10.2.3. Otherwise, perform a load test in accordance approximately twice the service load level under with 8.10.2.4. nonseismic conditions. These tests are not intended to simulate all possible loading conditions that may occur in an earthquake 8.10.2.3 Torque test—Torque the anchors alternately in or intended to represent the degree of cracking that might occur increments of 0.2Tinst. After each increment, inspect the in plastic hinge regions of reinforced concrete structures. concrete surface for cracks. Stop the test when splitting or steel failure prevents the torque from being increased 8.12.1 Purpose—These optional tests are intended to further. For each test, simultaneously record the torque at evaluate the performance of anchors in seismic tension, first formation of a hairline crack at one or both anchors and including the effects of cracks, but without edge effects. the maximum torque that can be applied to the anchors. Qualification for seismic loading shall only be considered in the context of a cracked concrete test program in accordance with 8.10.2.4 Load test—Install anchors according to the Table 3.2. MPII using the minimum specified spacing and edge distances. Load the anchor group in tension to failure as an 8.12.2 General test conditions—Test each anchor diameter at unconfined test. embedments as specified in Table 3.2. Install the anchor in a closed crack in accordance with 4.8. If no torque is specified 8.11—Tests to determine shear capacity of anchor by the MPII, finger-tighten the anchor prior to testing. Open elements with nonuniform cross section the crack by Δw = 0.5 mm, where Δw is additive to the width of the closed hairline crack after anchor installation. Subject Refer to Table 3.1, Test 12; Table 3.2, Test 16; and Table 3.3, the anchors to the sinusoidal tension loads specified in Table 8.2 Test 13. and Fig. 8.3 with a cycling frequency between 0.1 and 2 Hz, whereby Neq is given by Eq. (8-2), Nm is given by Eq. (8-3), 8.11.1 Purpose—This test is performed to evaluate the and Ni is given by Eq. (8-4). shear capacity of anchors as governed by element shear failure in situations where the shear capacity cannot be  -f-c-f-,c--t,-e-t-es--t-s-,t-2-- n reliably calculated.  Neq = 0.5 No, i N (8-2) R8.11.1 Where the cross-sectional area of the anchor shear plane is less than a threaded section of the same where nominal diameter within five anchor diameters of the shear plane, the shear capacity may be affected by the reduced No,i = mean tension capacity from reference service- section. Additionally, shallow anchors that exhibit pullout condition tension tests in low-strength cracked failure in unconfined tension tests may exhibit shear strengths away from edges that are below those predicted by concrete (Table 3.2, Test 11c), N; ACI 318M, Appendix D. Tests shall be performed to estab- lish the appropriate shear capacity in these cases. For fc,test = compressive strength of concrete used at time of anchors assessed for use in cracked concrete and resisting testing, MPa; seismic loads, it may be advantageous to establish the reference shear capacity of the anchor system in cracked fc,test,2 = concrete compressive strength corresponding to concrete. the tests used to establish No,i, MPa; and 8.11.2 General test conditions—Perform shear tests in n = normalization exponent determined in accordance uncracked concrete away from edges in accordance with ASTM E488. with 10.2. Nm = -N----e--q N (8-3) 2

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 37 Fig. 8.3—Required load history for simulated seismic Fig. 8.4—Required load history for simulated seismic shear test. tension test. Table 8.2—Required loading history for simulated Table 8.3—Required loading history for simulated seismic tension test seismic shear test Load level Neq Ni Nm Load level ±Veq ±Vi ±Vm Number of cycles 10 30 100 Number of cycles 10 30 100 Ni = N-----e--q----+----N-----m- N (8-4) parallel to the direction of the crack, whereby Veq is given by 2 Eq. (8-5), Vm is given by Eq. (8-6), and Vi is given by Eq. (8-7). 8.12.2.1 Record the crack width, anchor displacement, Veq = 0.5Vo, if--c-f-,c--t,-e-t-es--t-s-,t-2-- N (8-5) and applied tension load in accordance with 4.8. Following completion of the simulated seismic-tension cycles, open the where = mean shear capacity of anchors from reference crack to a width not less than the crack opening width as Vo,i service-condition tests in uncracked, low- measured at the end of the cyclic test and load the anchor in strength concrete (Table 3.2, Test 16), N; tension to failure. Record the maximum tension load, that is, fut,test residual tension capacity; the corresponding displacement; fut,test,2 = specified ultimate tensile strength of steel and plot the load-displacement response. anchor elements used in seismic tests, MPa and 8.13—Simulated seismic shear tests = measured ultimate tensile strength of steel Refer to Table 3.2, Test 18. anchor elements used in reference service- condition tests, MPa. R8.13 Simulated seismic shear tests are performed in cracks that are parallel to the load direction. Load cycling Vm = -V---e---q N (8-6) may be conducted at a relatively low frequency because the 2 loading rate has not been determined to be a significant factor in anchor performance. The use of a ramped loading Vi = V----e---q---+-----V----m- N (8-7) function through the zero point of the cyclic load may be 2 advantageous for operation of the testing apparatus. 8.13.2.1 If the service-condition shear tests have not 8.13.1 Purpose—These optional tests are intended to evaluate the performance of anchors subjected to seismic shear been performed, Veq shall be permitted to be evaluated in loads, including the effects of concrete cracking. Qualification accordance with Eq. (8-8). for seismic loading shall only be considered in the context of a cracked concrete test program as given in Table 3.2. Veq = 0.35Ase fut,test N (8-8) 8.13.2 General test conditions—Test each anchor diameter 8.13.2.2 The frequency of loading shall be between 0.1 at embedments as specified in Table 3.2. Install the anchor in a and 2 Hz. To reduce the potential for uncontrolled slip during closed crack in accordance with 4.8. If no torque is specified by load reversal, the alternating shear loading shall be permitted the MPII, finger-tighten the anchor prior to testing. Test inter- to be approximated by the application of two half-sinusoidal nally-threaded anchors with the bolt specified by the manufac- load cycles at the desired frequency connected by a reduced- turer and report the bolt type (refer to Table 11.1 or Table 11.2 speed ramped load, as shown in Fig. 8.5. for forms). Open the crack by Δw = 0.5 mm, where Δw is addi- tive to the width of the initial hairline crack after anchor instal- 8.13.2.3 Record the crack width, anchor displacement, lation. Subject the anchors to the sinusoidal shear loads and applied shear load in accordance with 4.8. Plot the load- specified in Table 8.3 and Fig. 8.4, with the shear load applied displacement history in the form of hysteresis loops.

38 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Table 9.1—Materials for concrete round robin tests Mixture Coarse Fine Cementitious material design aggregate aggregate Normalweight A Normalweight ASTM C150 Type II cement Normalweight B ASTM C150 Type II cement Normalweight combined with 25% Class F fly ash conforming to ASTM C618 Fig. 8.5—Permitted approximation of seismic shear cycle. laboratory for the assessment of the service-condition tension capacity in low-strength concrete, each laboratory 8.13.2.4 Following completion of the simulated seismic- shall provide round-robin tests. shear cycles, open the crack to a width not less than the crack opening width as measured at the end of the cyclic shear test 9.1.5 Each of the four laboratories performing round-robin and load the anchor parallel to the crack in shear to failure. tests shall be located in a different geographic region of Record the maximum shear load or residual shear capacity North America, whereby the geographic regions shall be and the corresponding displacement, and plot the load- defined by time zone as follows: Region 1: Pacific Time Zone; displacement response. Region 2: Mountain Time Zone; Region 3: Central Time Zone; and Region 4: Eastern and Atlantic Time Zones. Aggregates CHAPTER 9—SUPPLEMENTAL TEST used for the concrete shall be representative of typical concrete 9.1—Round-robin tests production in each laboratory’s immediate geographic loca- tion. It shall be permitted, however, to transport specimens Refer to Table 3.1, Test 13; Table 3.2, Test 19; and Table 3.3, prepared by the regional laboratories in the different Test 14. geographic regions to the primary testing laboratory for testing. R9.1 The relationship between concrete composition and 9.1.5.1 If the primary laboratory is located outside of adhesive anchor performance is not well understood. North America, four secondary laboratories, each located in Anecdotal evidence indicates there may be a direct relationship a different geographic region in North America, shall be between aggregate types used and bond strength. Round- selected by the primary laboratory and round-robin tests robin tests are intended to establish the consistency of bond shall be provided by the secondary laboratories only. The properties of the tested system over a range of concrete aggregates used for the concrete shall be representative of mixture designs originating from various geographic regions. typical production in each laboratory’s geographic location. Two mixture designs—one without and one with fly ash as a cement replacement—are intended to provide a representa- 9.1.6 For the purpose of round-robin testing, each tive sample of concrete compositions in North America. secondary laboratory shall cast unreinforced concrete test members 300 mm thick with minimum plan dimensions of 9.1.1 Purpose—These round-robin tests are performed to 1.2 x 0.9 m from normalweight concrete using mixture calibrate adhesive anchor test results for regional variations designs formulated to achieve 21 ± 3.5 MPa at the time of in concrete. testing. Mixture designs shall be in accordance with 4.3 and 9.1.6. Aggregates shall be in accordance with 4.3.2. Test 9.1.2 General test conditions—Perform round-robin member strength shall be confirmed based on field prepared tension tests on anchor diameters and embedments as and cured cylinders in accordance with 4.4.3.2. Concrete specified in Table 3.1, 3.2, or 3.3. shall be produced from Mixture Designs A and B with materials in accordance with Table 9.1. 9.1.3 Round-robin tension tests shall be performed by the primary testing laboratory and three additional independent 9.1.7 Install anchors in accordance with the MPII. Perform laboratories (also known as secondary laboratories) accredited a minimum of five confined and five unconfined tension tests for testing adhesive anchors in accordance with Chapter 12. to failure on anchors in concrete produced in accordance with The three additional independent laboratories shall be Mixture Design A and a minimum of five confined and five selected by the primary testing laboratory and accredited for unconfined tension tests to failure in concrete produced in testing of anchors according to ASTM E488. accordance with Mixture Design B. Perform tests in accordance with 4.7 within the concrete age interval of 28 to 56 days. 9.1.4 All round-robin tests shall be conducted with ASTM Confined round-robin tests may be omitted, however, if A193 B7 Unified National Coarse (UNC) threaded rod Eq. (9-1) is fulfilled. anchors. If steel failure occurs, the embedment depth shall be reduced for all round-robin tests. Anchor test specimens k ≤ 10 sampled in accordance with 4.2 shall be provided by the primary testing laboratory to the three additional laboratories. where Where the primary laboratory uses data from more than one k = h----e1--.f-5-----N-f--c-u-,--t-e--s--t--,-i- (9-1)

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 39 Nu is the mean ultimate tension load in unconfined round- where robin tests, N. Fi = test result normalized to considered concrete 9.2—Tests to determine minimum member strength i, N; thickness Fu,test,x = test result from test series x, N; Refer to Table 3.1, Test 14; Table 3.2, Test 20; and fc,i = concrete compressive strength corresponding Table 3.3, Test 15. to concrete to which the test result shall be R9.2 The determination of alternate minimum member normalized, MPa; thicknesses hmin is permitted through testing conducted in accordance with this section. Refer also to 8.9 and 8.10. fc,test,x = concrete compressive strength corresponding to concrete used for test series x, MPa; and 9.2.1 Purpose—These optional tests are performed to check the minimum member thickness hmin specified by the n = 0.5 for concrete breakout and splitting failure manufacturer. or shall be determined from tests when failure under tension load is characterized by pullout 9.2.2 General test conditions—Test anchor diameters and or when tests are performed as confined tests. embedments as specified in Table 3.1, 3.2, or 3.3. 10.2.4 Anchor element failure 9.2.2.1 Perform a minimum of 10 installation tests for the maximum embedment depth hef associated with each 10.2.4.1 Where failure is characterized by metal rupture, anchor diameter to demonstrate that hole drilling and instal- normalize the capacity for nominal anchor element material lation (for example, setting and torquing of the anchor) does strength using Eq. (10-2). For steels conforming to a standard, not result in cracking or breakthrough of the concrete test the characteristic tensile strength shall be taken as the member. A test shall consist of drilling the hole, setting the minimum specified tensile strength futa. anchor, and inspecting the test member for visible concrete cracking or spalling. For the purpose of these tests, support Fu = Fu, test, x -----f--u--t--a----- N (10-2) the test member, that is, slab and beam, with a shear span fu, test, x length, which is the distance from anchor to support, not less than 1.5hef. Use drilling equipment and setting procedures where that are representative of normal anchor installation as specified by the anchor manufacturer. Fut = normalized test result, N; Fu,test,x = test result from test series x, N; 9.2.2.2 Instead of 9.2.2.1, tests in accordance with 8.9 futa = specified steel tensile strength to which the and 8.10 shall be permitted to be conducted with the test member supported with a shear span length not less than test result shall be normalized, MPa; and 1.5hef. Drilling equipment and setting procedures shall be representative of normal anchor installation as specified by fu,test,x = measured steel tensile strength corresponding the manufacturer. Subsequent to drilling the holes and to anchors used for test series x, MPa. setting anchors, the balance of tests in accordance with 8.9 and 8.10 shall be permitted, conducted without supports. 10.3—Establishing characteristic values R10.3 Establishment of characteristic values is based on factors for one-sided tolerance limits for normal distributions. 10.3.1 Evaluate the characteristic value—for example, Nk, Np, Ns, and Vs—from the mean value and the associated coefficient of variation v using Eq. (10-3). CHAPTER 10—ASSESSMENT OF ANCHORS Fk = Ftest,x(1 – K · νtest,x) (10-3) 10.1—Analysis of data where = tolerance factor corresponding to a 5 percent Analyze data according to the procedures of this chapter and K probability of nonexceedence with a confidence of 90 percent derived from a noncentral t- report the results according to the requirements of Chapter 11. Fk distribution for which the population standard Ftest,x deviation is unknown (values for specific 10.2—Normalization of anchor capacities for νtest,x samples sizes n are provided in Table 10.1); measured concrete bond and steel strengths = characteristic value (5 percent fractile), N; R10.2 Normalization to 17 MPa is based on the minimum = mean of test results for test series x, N; and concrete compressive strength permitted by ACI 318M. = coefficient of variation of the population 10.2.1 Consider the failure type when reporting results and sample corresponding to test series x, percent. data and comparing anchor capacities of tests that require normalization to a specific or a common strength. 10.4—Assessment of characteristic tension capacity associated with concrete breakout and 10.2.2 Normalize all test results to a concrete compressive pullout strength of 17 MPa and report according to the requirements of Chapter 11, unless otherwise specified by this standard. 10.4.1 Adjustment for regional variations in concrete 10.2.3 Concrete breakout, splitting, and pullout failure (Section 9.1) 10.2.3.1 Normalize test results for the influence of the R10.4.1 Variations in adhesive anchor bond strength as concrete compressive strength in accordance with Eq. (10-1). determined from round-robin tests is reflected in the value of  f--c--,-f-t-ce--,s--it--,-x-- n  Fi = Fu, te s t, x N (10-1)

40 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Table 10.1—K values for 5 percent probability of value of αconc shall be calculated for each laboratory and nonexceedence with a confidence of 90 percent applied to the service-condition tension tests originating Number of tests n K Number of tests n K from that laboratory. 3 5.311 21 2.190 4 3.957 22 2.174 -τ--r--e--f--,--f-c > 1.05  αconc = τ---r--e--f--,--f-c (10-5a) 5 3.400 23 2.159 τu, fc τu, fc 6 3.092 24 2.145 7 2.894 25 2.132 -τ--r--e---f-,--f-c < 0.95  αconc = τ---r--e---f-,--f-c (10-5b) 8 2.754 26 2.120 τu, fc τu, fc 9 2.650 27 2.109 10 2.568 28 2.099 0.95 ≤ τ---r--e---f-,--f-c ≤ 1.05  αconc = 1 (10-5c) 11 2.503 29 2.089 τu, fc 12 2.448 30 2.080 13 2.402 35 2.041 where 14 2.363 40 2.010 15 2.329 45 1.986 τu,fc = mean bond stress from unconfirmed round- 16 2.299 50 1.965 robin service-condition tests in uncracked 17 2.272 60 1.933 18 2.249 120 1.841 concrete normalized to concrete strength fc = 19 2.227 240 1.780 21 MPa in accordance with Section 10.2, MPa; 20 2.208 ∞ 1.645 or the mean bond stress from confirmed round- robin reference tests in uncracked concrete α conc. Testing in conformance with round-robin testing normalized to concrete strength fc = 21 MPa requirements may result in significant scatter and adjustment of in accordance with Section 10.2, MPa; and the characteristic bond stress from round-robin testing should be limited to cases where there is a clear trend. As τref,fc = as per Eq. (10-4). such, a 5 percent tolerance on the ratio of the round-robin bond stress to the reference bond stress is included in the 10.4.2 Requirements on coefficient of variation assessment. Where confined tests have been performed in accordance with Section 9.1.7, the value of α conc corresponding R10.4.2 The limits of 20 and 15 percent on the coefficient to the confined tests should be used in Eq. (10-12). of variation (COV) for reliability and reference/service- 10.4.1.1 The primary testing laboratory shall determine the mean bond stress τref,fc from the results of the combined condition tests, respectively, are derived from extensive round-robin tests in accordance with Eq. (10-4). If the mean bond stress corresponding to the tests conducted in any one experience with adhesive anchor testing. For systems that laboratory exceeds the mean of the combined results from the remaining three laboratories by more than 15 percent, exhibit larger variation, a reduction is taken on the bond discard that test series and use the remaining three test series to establish τref,fc. Perform this evaluation separately for the stress in the form of α COV. results for unconfined and confined tests. 10.4.2.1 In each reliability test series, the (COV)νtest,x of the peak loads shall not exceed 30 percent. For all other test series, the (COV)νtest,x of the peak loads shall not exceed 20 percent. 10.4.2.2 For cases where the (COV)νtest,x of the peak loads in reliability tests exceeds 20 percent, determine a reduction factor αCOV in accordance with Eq. (10-6). 10.4.2.3 For cases where the (COV)νtest,x of the peak loads in tests other than reliability tests exceeds 15 percent, determine τref, fc = -πF---d-t-e-a-s--ht-,--fe-c-f MPa (10-4) a reduction factor αCOV in accordance with Eq. (10-6). 10.4.2.4 The minimum value of αCOV as determined in accordance with Sections 10.4.2.2 and 10.4.2.3 shall control for where the determination of τk(cr,uncr) in accordance with Eq. (10-12). τref,fc = normalized mean bond stress corresponding αCOV = 1-----+-----0---.-0---3----(--ν---t--1e--s--t-,--x----–----C-----O----V----)- ≤ 1.0 to round-robin tests, MPa; and (10-6) Ftest,fc = mean peak load for all round-robin tests normalized to concrete strength fc = 21 MPa in where νtest,x is the sample coefficient of variation for test accordance with Section 10.2, N. series x equal to the mean divided by the sample standard deviation, percent, and COV is the threshold COV for adhesive 10.4.1.2 Based on the results of all round-robin testing, anchors, percent (20 for peak loads from reliability tests and 15 for peak loads from tests other than reliability tests). evaluate the adjustment factor αconc in accordance with Eq. (10-5) separately for unconfined and confined round- 10.4.3 Comparison with reference tests robin tests. The minimum value of αconc shall be used in R10.4.3 The assessment for performance in reliability Eq. (10-12). Where the primary laboratory uses data from tests is conducted through the determination of α-values that more than one laboratory for the assessment of service- condition tension capacity in low-strength concrete, a unique

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 41 Table 10.2—Minimum limiting characteristic bond stress τk,min, in MPa Table 3.1 Table 3.2, Table 3.3 Uncracked Reduction factors included in the evaluation of τk(cr,uncr) in accordance with Eq. (10-12) Uncracked Cracked concrete concrete concrete β αlt αst αdur αρ αconc αCOV αcat3 4.5 4.5 1.4 β — — — αρ αconc αCOV αcat3 7 7 2.1 Table 10.3—Reliability tests relevant for determination of min(α/αreq) and minαadh in Eq. (10-12) Table 3.1 Table 3.2 Table 3.3 Test no. Test no. Test no. 3 4 5* 3 4 5 6 7 8* 3 4 5 6* *Optional tests. Table 10.4—Service-condition tests relevant for determination of min(α/αreq) and minαadh in Eq. (10-12) Table 3.1 Table 3.2 Table 3.3 Test no. Test no. Test no. 7a 7b 8a 8b* 8c 11a 11b 11c 11d 12a 12b* 12c 17 8a 8b 9a 9b* 9c *Optional tests. are, in turn, compared with limiting values α req , below the concrete and the adhesive matrix, is generally determined which a reduction in the bond stress is required. by examination of the load-slip curve. Where this is not possible, rules are provided for consistent determination of 10.4.3.1 For those reliability tests listed in Tables 3.1, Nadh. Where the measured load at loss of adhesion is less 3.2, or 3.3 for which αreq is defined, calculate the value of α than 50 percent of the mean tensile strength, which is generally using Eq. (10-7) and the results of reference tension tests an undesirable response, a reduction in the bond stress is taken through the factor α adh. conducted in the same test member or concrete batch with 10.4.4.1 Uncontrolled slip under tension load corresponds anchors having the same diameter. to the loss of adhesion between the adhesive material and the concrete. Upon loss of adhesion, both the anchor element α = min τ---u--,--i ; τ---τk--,k--,o--i,--i (10-7) and adhesive material are extracted together from the τo, i concrete. In such cases, the subsequent load-slip behavior is substantially dependent on the roughness of the drilled hole. where The onset of uncontrolled slip is therefore defined as loss of τu,i = mean bond stress from reliability test series in adhesion and the load corresponding to loss of adhesion is denoted as Nadh. concrete batch or test member i, MPa; τo,i = mean bond stress from reference test series in 10.4.4.2 Evaluate the load Nadh for each test of the reliability test series (Table 10.3), the service-condition test series concrete batch or test member i, MPa; (Table 10.4), and the reliability tests (Table 10.5 or 10.6). τk,i = characteristic bond stress from reliability 10.4.4.3 Evaluate the load Nadh by examination of the test series in concrete batch or test member i load-displacement curve recorded during the test conduct. In calculated in accordance with Section 10.3, general, loss of adhesion is characterized by a significant MPa; and change in stiffness as reflected in an abrupt change in the slope τk,o,i = characteristic bond stress from reference test of load-displacement curve (Fig. 10.1(a)). series in concrete batch or test member i calcu- lated in accordance with Section 10.3, MPa. 10.4.4.4 In cases where the load corresponding to loss of adhesion may not readily be identified by direct observation 10.4.3.2 Omit comparison of the 5 percent fractile values of the load-displacement curve, evaluate the load Nadh as if either of the following conditions is met: follows. • For both test series, the COV of the failure loads v ≤ 1. Compute the tangent to the load-displacement curve at a 10 percent; or load N = 0.3Nu, where Nu is the peak tension load resisted by the anchor in the test. In general, the tangent stiffness • The difference in the number of tests in the series to be ktan can be conservatively estimated as the secant stiffness compared is Δn ≤ 5 and the COV of the reliability test between the origin of the load-displacement curve and the series is equal to or less than the COV of the reference point defined by 0.3Nu and Δ0.3 in Eq. (10-8). test series. 10.4.4 Requirements for load-displacement behavior R10.4.4 The point at which the adhesive anchor loses initial adhesion to the concrete and begins to slip, with further resistance provided by the rough interface between

42 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY (a) Nadh at loss of adhesion. (c) Nadh when peak load is before Δ lim. (b) Nadh when peak load-displacement is after Δ lim. (d) Nadh when Δ 0.3 < 0.05 mm Fig. 10.1—Evaluation of Nadh load under different load-displacement conditions. Table 10.5—Anchor categories for adhesive Table 10.6—Anchor categories for adhesive anchors subject to installation conditions anchors subject to installation conditions according to Table 10.7* according to Table 10.8* Threshold value of αreq for selected reliability tests Threshold value of αreq for selected reliability tests Anchor Reliability test numbers according to Anchor Reliability test numbers according to 2h†§ category Table 3.1, Table 3.2, or Table 3.3 category 2a Table 3.1, Table 3.2, or Table 3.3 2a 2b 2c† 2d† 2e 2b 2c† 2d† 2e 2f‡§ 2g†§ 1 0.95 0.90 0.90 0.90 0.95 1 0.80 0.75 0.75 0.75 0.80 0.90 0.90 0.90 2 0.80 0.75 0.75 0.75 0.80 2 0.70 0.65 0.65 0.65 0.70 0.75 0.75 0.75 3 0.70 0.65 0.65 0.65 0.70 3 0.60 0.55 0.55 0.55 0.60 0.65 0.65 0.65 *(periodic special inspection) *(continuous special inspection and on-site proof loading program) †Optional tests; refer to Table 10.7 for permissible combinations. †Optional tests; refer to Table 10.8 for permissible combinations. ‡If Test 2g is performed, then Test 2f may be omitted. §Omission of less severe tests is permitted in specific cases: for example, if the desired category is fulfilled with the results of Tests 2b, 2c, and 2d, then Tests 2f, 2g, and 2h may be omitted.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 43 ktan ≈ -0--Δ-.-3--0-N-.-3---u-–--–--Δ---N-o---ro--ir-g-i-i-g-n-i--n (10-8) over that measured in unconfined testing because confined testing restrains splitting cracks and provides for a triaxial where Δ0.3 is the anchor displacement at N = 0.3Nu. stress state under the bearing plate. For anchor systems 2. Multiply the tangent stiffness by 2/3. evaluated using the reduced test program of Table 3.3, the bond strength in cracked concrete is given as 25 percent of 3. Project a straight line from the origin of the load- the value determined in uncracked concrete. The determina- tion of the limiting characteristic bond stress to be used in displacement curve with a slope corresponding to the the design equations of ACI 318M, Appendix D is based on a range of factors that may or may not apply in each case. It is stiffness as calculated in No. 2. therefore permissible to determine a range of limiting charac- teristic bond stress values associated with specific conditions. 4. The load Nadh shall be taken from the point of intersection between the projected line and the measured load- 10.4.5.1 Calculate the corresponding bond stress τi for each service-condition tension test (Table 3.1, Tests 7a and 7b; displacement curve (Fig. 10.1(b)). Table 3.2, Tests 11a through 11d; and Table 3.3, Tests 8a and 8b) in concrete test member i or concrete batch i, normalized 5. If the peak load occurs at a displacement that is less to concrete strength equal to 17 MPa using Eq. (10-11). than that corresponding to the intersection of the τi = αsetup-πN---d-u--a-,--ih-,--fe-c-f (10-11) projected line and the load-displacement curve, then where Nadh shall be taken as the peak load (Fig. 10.1(c)). 6. If the displacement Δ0.3 ≤ 0.05 mm, the origin of the projected line shall be shifted to a point on the load- displacement curve given by 0.3Nu and Δ0.3 (Fig. 10.1(d)). 10.4.4.5 For all values of Nadh calculated in accordance with Section 10.4.4.3 or 10.4.4.4, evaluate the adjustment factor αadh using Eq. (10-9). --N----a---d--h--,--i-,--j-- ≤ 1.0 Nu,i,fc = peak tension load measured in a tension test 0.5Nu, i, j conducted in test series i or concrete batch i, αadh = (10-9) normalized to concrete strength fc = 17 MPa, N; and where αsetup = 1.0 if service-condition tests are performed as unconfined tests, 0.75 if service-condition Nadh,i,j = tension load corresponding to loss of adhesion for Test Series i, Test j, N; and tests are performed as confined tests, and Nu,i,j = peak tension load corresponding to Test 0.70 if service-condition tests in cracked Series i, Test j, N. concrete are performed as confined tests. 10.4.4.6 In cases where a minimum of 10 replicates have 10.4.5.2 Nominal characteristic bond stress been performed in a given test series, it shall be permitted to calculate αadh for that test series in accordance with Eq. (10-10) 10.4.5.2.1 Calculate the nominal characteristic bond instead of Eq. (10-9). stress value τk,nom(cr,uncr) from the values τi in accordance with Eq. (10-3). 10.4.5.2.2 If the bond stress can be shown to vary with αadh = -m----i--n---N----a---d--h--,--i ≤ 1.0 anchor diameter in a nonrandom manner, report the bond 0.5Nu, i (10-10) stress as a continuous function of anchor diameter. Other- wise, calculate a single bond stress τk,nom(cr,uncr) with the results for all diameters using the lowest bond stress. where R10.4.5.2.2 While uniform bond stresses calculated in minNadh,i = minimum value of adhesion force determined accordance with Eq. (10-11) typically trend downward with for Test Series i, N; and increasing anchor diameter, the relationship between bond Nu,i = mean tension capacity for reliability Test Series i, N. stress and diameter may be system-dependent and may not 10.4.4.7 Where failure under tension load is characterized show a uniform trend. In this case, where the bond stress by slip between the anchor rod and adhesive material along the entire embedded length—as indicated by extraction of the rises and falls across several diameters in a random manner, threaded rod without adherence of adhesive to the rod— evaluation of the load corresponding to loss of adhesion is not the minimum derived bond stress should be taken across all required and the value of αadh shall be taken as 1.0. diameters. Where a trend can be established between bond 10.4.5 Bond stress stress and diameter, a best-fit approximation to the recorded R10.4.5 The calculation of bond stress, made on the basis of the uniform bond stress mode, is assumed essentially values should be established and used to establish unique independent of concrete strength within the concrete strength range addressed by ACI 318M, Appendix D. An bond stresses for each diameter as appropriate. adjustment is made for values determined through confined testing, which generally increases the measured peak load 10.4.5.2.3 For adhesive anchor assessed in accordance with Table 3.3, the value of τk,nom,cr shall be taken as τk,nom,cr = 0.25τk,nom,uncr. 10.4.5.3 Determination of limiting characteristic bond stress 10.4.5.3.1 For adhesive anchors qualified in accordance with Table 3.1, reduce the nominal characteristic bond stress

44 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY in uncracked concrete, τk,nom,uncr , in accordance with Eq. (10- 10.4.5.5 Further modify the limiting characteristic bond 12) and report the limiting characteristic bond stress in uncracked concrete, τk,uncr, for each combination of mandatory resistance τk(cr,uncr) for seismic tension load cases in and optional use conditions specified. accordance with Eq. (10-14). 10.4.5.3.2 For adhesive anchors qualified in accordance τk,seis(cr,uncr) = τk(cr,uncr)αN,seis MPa (10-14) with Table 3.2 or 3.3, reduce the nominal characteristic where tension bond stresses in cracked and uncracked concrete αN,seis = reduction factor for seismic tension loading τk,nom(cr,uncr) in accordance with Eq. (10-12) and report the (Eq. (10-30)); and limiting characteristic bond stresses in cracked concrete, τk,cr , and uncracked concrete, τk,uncr, for each combination τk,seis(cr,uncr)= seismic tension bond resistances in cracked of mandatory and optional use conditions specified. and uncracked concrete, respectively, MPa. τk(cr,uncr) = 10.4.5.6 Minimum limiting characteristic bond stress τk,nom(cr,uncr)βαltαstαdurαραconcαCOVαcat3 MPa (10-12) 10.4.5.6.1 The nominal characteristic bond stress evaluated in accordance with Eq. (10-12) shall not be less than that shown in Table 10.2. Where this condition is not where satisfied, the product shall be reported as unqualified. β = min[min(α/αreq); minαadh] for the reliability and R10.4.5.6.1 ACI 318M, Appendix D, contains default service-condition tests listed in Tables 10.3 and 10.4; α is the ratio of reliability test result to refer- minimum bond stresses that may be used for design in the ence test result evaluated for all reliability tests absence of direct information regarding the bond stresses listed in Table 10.3 (refer to Eq. (10-7)); αadh is the reduction factor for loss of adhesion as evalu- associated with common use conditions for a qualified ated for all reliability tests listed in Table 10.3 and product. Because any qualified product is assumed to be for all service-condition tests listed in Table 10.4 able to develop these minimum bond stresses, the same (10.4.4.2); values (as derived from Eq. (10-12) for the specific constella- αreq = threshold value of α given in Table 3.1, 3.2, or 3.3; tion of use parameters described in ACI 318M, Appendix D) αlt = reduction factor for maximum long-term must be taken as minimums for the qualification. A basic temperature (refer to Eq. (10-26)); differentiation is made between outdoor and indoor use. αst = reduction factor for maximum short-term temperature (refer to Eq. (10-27)); Outdoor implies exposure to weather such as water, αdur = reduction factor for durability (refer to Eq. (10-29)); temperature, and aggressive environments, while indoor is αρ = minimum reduction factor for reduced load in associated with a less demanding set of parameters. This is crack width cycling and freezing-and-thawing tests reflected in the omission of the α lt, α st, and α dur from the (refer to Eq. (10-16)); second higher set of bond stresses corresponding to indoor αconc = adjustment factor for regional concrete variation uses in ACI 318M, Appendix D (Table 10.2). (refer to Section 10.4.1); 10.4.6 Anchor category αCOV = reduction factor associated with the coefficient of variation of peak loads (refer to Eq. (10-6)); and R10.4.6 The anchor category is determined by the results of αcat3 = reduction factor for Anchor Category 3 (refer to Eq. reliability tests in terms of the same α-factors used to determine (10-15)). the limiting characteristic bond stress. Two sets of α req values are provided for determining the anchor category, each 10.4.5.3.3 If the value τk,cr is derived from service- condition tests in cracked concrete performed as confined associated with specific job-site inspection and testing tests, the value τk,cr shall not exceed αconc · τk,nom,cr , where τk,nom,cr is evaluated from service-condition tests in cracked requirements. For anchors that are assessed under the more concrete performed as unconfined tests and evaluated in relaxed threshold values for the determination of the anchor accordance with 10.4.5.2. category, more stringent requirements for job-site inspection 10.4.5.4 Further modify the limiting characteristic bond resistance τk(cr,uncr) for sustained tension load cases in and testing are required. For anchors that do not meet the accordance with Eq. (10-13). threshold values for the lowest anchor category, a further reduction in the limiting characteristic bond stress is taken. 10.4.6.1 Assign an anchor category to the tested anchor system in accordance with Table 10.5 or 10.6, depending on the installation conditions specified for the anchor and the results of the reliability tests. The minimum value of α and αadh shall control for the determination of the anchor category. τk,sust(cr,uncr) = τk(cr,uncr)αρ,sust MPa (10-13) 10.4.6.2 Where the controlling value of α or αadh is less than the value of αreq corresponding to Anchor Category 3 where in Table 10.5 or 10.6, the anchor shall be assigned to Anchor αρ,sust = reduction factor for sustained tension loading Category 3 and an additional reduction factor αcat3 for the in accordance with Eq. (10-17); and determination of τk(cr,uncr) in accordance with Eq. (10-12) τk,sust(cr,uncr)= the sustained tension loading bond resistance, shall be determined in accordance with Eq. (10-15). For all MPa. other cases, αcat3 shall be taken as 1.0.

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 45 αcat3 = min min-α---r--e---qα--,--c--a--t--3; minα----r-α-e---qa--,-d-c-h-a--t--3 ≤ 1.0 (10-15) τ---u--,---f-c-,--u---n--c--r--π----d---a- 2 mm (10-18) hef = ----------k---m---f,-c-u-′-n---c--r---------- where αreq,cat3 = αreq corresponding to Anchor Category 3 where mean bond strength evaluated from unconfined for corresponding reliability test in accordance with Table 10.5 τu,fc,uncr = tests in uncracked concrete normalized to fc′ , or 10.6. MPa; and km,uncr = 10.4.6.3 The anchor category shall be reported in 17 for recognition of kuncr = 13, and 15 for Table 11.1 or 11.2. recognition of kuncr = 11. 10.4.7 Adjustment for reduced load in crack width 10.5—Assessment of steel tension capacity cycling, freezing-and-thawing, and sustained load tests is R10.5 Where the strength of the anchor element is permissible if the limiting characteristic bond stress is reduced (10.9, 10.10, and 10.11). addressed by other standards, for example, all-thread rods by ASTM, separate tension tests to determine the tension R10.4.7 Sustained loads are required for the crack width strength of the rod/nut assembly are not required. cycling test, the freezing-and-thawing test, the standard temperature creep tests, and the maximum long-term 10.5.1 Evaluate the steel tension capacity in accordance temperature creep tests. If the sustained load used in the test with D.5.1.2 of ACI 318M. is less than required, a reduction on the limiting characteristic bond stress is taken. 10.5.2 Where the steel anchor element carrying tension load has a variable cross section, Ase,N shall be taken as the 10.4.7.1 Where a reduced sustained load is required to minimum cross-sectional area over the load-bearing length meet the displacement requirements in the crack width of the anchor. cycling or freezing-and-thawing tests, the reduction factor αρ shall be evaluated in accordance with Eq. (10-16). αρ = min -N----r--e--d ≤ 1.0 (10-16) 10.6—Assessment of steel shear capacity (8.11) Nreq 10.6.1 For anchors without a reduced cross section within where five diameters of the shear plane, the steel shear capacity shall be evaluated in accordance with D.6.1.2 of ACI 318M. Nred = reduced sustained load in a reliability test series as required to satisfy displacement criteria, N; and R10.6.1 In no case shall the shear strength of an anchor element exceed the value given in ACI 318M, Appendix D. Nreq = required sustained load for a reliability test series—Nw for tests in accordance with Eq. (7-1), 10.6.1.1 For anchors without threads in the critical shear and Nsust,ft for tests in accordance with Eq. (7-2), N. plane, Ase,V shall be taken as the gross anchor cross-sectional area. 10.4.7.2 Where a reduced sustained load is required to 10.6.1.2 For anchors with threads in the shear plane but meet the displacement requirements in the sustained load without a reduced cross section, Ase,V shall be taken in accordance with Eq. (10-19). test, the reduction factor αρ,sust shall be evaluated in accordance with Eq. (10-17). ----N----r--e--d--- -π4-  0---.--9--n-7--t-4---3-  2 mm2 Nsust, lt  αρ, sust = min ≤ 1.0 (10-17) Ase, V = da – (10-19) where where nt is the number of threads per millimeter. 10.6.1.3 For anchors that exhibit pullout failure in Nred = reduced sustained load applied in the sustained load test as required to satisfy displacement unconfined tension tests at hef = hef,min , determine the criteria, N; and characteristic shear capacity Vs by test as prescribed in 8.11, but Vs shall not exceed the value determined in accor- Nsust,lt = sustained load in accordance with Eq. (7-3), N. dance with D.6.1.2 of ACI 318M, where Ase is as defined 10.4.8 Determination of effectiveness factors in 10.6.1.1 or 10.6.1.2. 10.4.8.1 It shall be permitted to evaluate the effectiveness 10.6.2 For anchors with a reduced cross section within five factors kcr and kuncr for adhesive anchors in accordance with ACI 355.2. Unconfined tension tests shall be conducted at diameters of the shear plane, the characteristic shear capacity the smallest, middle, and largest diameters in low- and high- strength concrete with five replicates per test series. The tests Vs shall be determined by test as prescribed in 8.11, but shall shall be conducted at the greatest embedment depth for not exceed the value determined in accordance with D.6.1.2 which concrete cone failure is anticipated to occur and may be approximated using Eq. (10-18). The assessment of the of ACI 318M, assuming an unreduced cross section. effectiveness factor shall fulfill the requirements of ACI 355.2 for all test series. 10.6.3 Further modify the characteristic shear capacity Vs for seismic load cases in accordance with Eq. (10-20) Vs,seis = VsαV,seis N (10-20)

46 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY where N95% = 95 percent fractile (90 percent confidence) of αV,seis = reduction factor for seismic shear loading, Nk,test the induced tension force corresponding to 1.3Tinst; refer to Eq. (10-31); = characteristic tension capacity evaluated Vs = characteristic steel shear capacity determined from reference tension tests in low-strength in accordance with 10.6.1 or 10.6.2; and concrete (Table 3.1, Test 1a; Table 3.2, Test 1a; and Table 3.3, Test 1a), N; and Vs,seis = seismic shear capacity of the anchor as governed by steel failure. Fy = Ase,N fya for bolts with a defined yield stress and Fy = Ase,N ⋅ 0.8futa for bolts without a 10.6.4 For anchor diameters not tested in shear, the minimum values of αV,seis determined for the tested anchor well-defined yield stress, MPa. diameters closest to the untested diameters shall be used in 10.8.2 It shall be permitted to satisfy the requirement of Eq. (10-20). Eq. (10-22) using a calculated value for N95% in accordance 10.6.5 Report shear capacities obtained in Table 11.1 or 11.2. with Eq. (10-23). 10.7—Assessment of minimum member thickness N95% = -1---.-3---T----i-n---s-t (10-23) (9.2) kf da R10.7 When anchors are to be installed with small back- where kf is the friction factor of threads. The friction factor shall be taken as a lower-bound value. For normal threaded side cover distance, which is the distance from the end of the rods without lubricants or friction-reducing coatings, k = 0.2 may be assumed. drilled hole to the remote concrete face, the impact energy of 10.9—Assessment of behavior under crack the drilling system is decisive for preventing spalling of the cycling (7.15) concrete at the remote face. R10.9 Compare Fig. 7.1 to Fig. 8.1 in ACI 355.2. Unlike expansion and undercut anchors, adhesive anchors do not 10.7.1 In those test series where the minimum member develop wedging forces in the crack during the conduct of the crack movement test. As such, changes in the lower crack thickness hmin is required to be used, conduct tests in width with increasing crack cycling are likely to be due to members having the minimum member thicknesses specified other causes, for example, changes in the bond relationship of the embedded reinforcement in the test specimen. for each anchor type, diameter, and embedment. The 10.9.1 In each test in cracks whose opening width is minimum member thickness hmin shall not be less than the cycled, the cumulative recorded anchor displacement shall value given by Eq. (10-21). not exceed 2 mm following the initial 20 cycles of crack opening and closing, nor 3 mm following 1000 cycles. hmin = hef + Δh ≥ 50 mm (10-21) 10.9.2 If the anchor displacement exceeds these limits where Δh ≥ 2do ≥ 30 mm applies to all anchor types without during the crack-cycling portion of the test, it shall be restriction and Δh ≥ 2do ≥ 15 mm applies to all anchor types permitted to increase the number of replicates. For a sample in cases where the remote face of the concrete member can size of 10 to 20 replicates, one of the tested anchors shall be permitted to exhibit a maximum displacement of 3 mm after be inspected. If concrete breakthrough occurs during the initial 20 cycles and 4 mm after 1000 cycles. For sample sizes larger than 20, 5 percent of the tested anchors shall be drilling, take measures to ensure that the effective anchor permitted to exhibit these increased displacements. If the requirements are not met, repeat the tests with a reduced embedment has not been compromised and that adhesive sustained load until the requirements are met and evaluate the material losses are prevented (Δh = 0 applies to injection reduction factor αρ in accordance with 10.4.7. For anchors anchor systems in cases where the effective anchor embedment evaluated in accordance with Table 3.3, reduction of the sustained load is not permitted and anchors that fail to satisfy is adjusted for spalling on the backside of the concrete the displacement requirements of this section are not qualified for use in cracked concrete in accordance with this standard. member and measures are taken to ensure that adhesive 10.9.3 The value of αreq for the residual tension capacity material losses are prevented). is 0.90. 10.8—Assessment of maximum tightening torque 10.9.3.1 For assessment under Table 3.3, the reference (7.19) value for cracked concrete used to determine α shall be 0.25 times the reference value in uncracked concrete, normalized R10.8 Because the relationship between torque and to 17 MPa. tension in a bolted connection is highly dependent on the condition of the threads, fraying surfaces, and the presence of lubricants or contaminants, the specific conditions associated with the reported torque value should be stated. 10.8.1 The torque test shall achieve a torque resistance of at least 1.3Tinst. The anchor shall not turn in the anchor hole prior to reaching a torque resistance of 1.3Tinst. In addition, Eq. (10-22) shall be fulfilled. If this requirement is not met, reduce the installation torque Tinst as required to fulfill the requirement. N95% ≤ min[Fy; 0.8Nk,test] (10-22) where

QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY 47 10.10—Assessment of freezing-and-thawing measured in the corresponding reference tests at standard behavior (7.16) temperature or maximum long-term elevated temperature, respectively. It shall be permitted to omit the sustained load 10.10.1 The change in displacement as a function of time tests at standard temperature, however, if the displacements measured in the sustained load tests at long-term temperature in the freezing-and-thawing tests (7.16) shall continually are extrapolated to 50 years and the mean value Δservice does not exceed Δlim as defined in 10.11.3. decrease with an increasing number of freezing-and-thawing 10.11.4 The calculated estimated displacement Δservice for cycles and shall approach zero. any one test shall not exceed 1.2Δlim with Δlim as defined in 10.11.3. 10.10.2 If the requirement on displacement is not met, 10.11.5 If the requirement on displacement is not met, reduce the sustained load until the requirement is met and reduce the sustained load until the requirement is met and evaluate the reduction factor αρ in accordance with 10.4.7. evaluate the reduction factor αρ,sust in accordance with 10.4.7. The applied sustained load shall not be less than 40 percent of 10.10.3 The value of αreq for the residual tension capacity Nsust,lt as determined in accordance with Eq. (7-3). shall be 0.90. 10.11.6 The value of αreq for the residual tension capacity 10.11—Assessment of sustained load behavior shall be 0.90. (7.17) 10.12—Assessment of performance associated R10.11 Equation (10-24) provides a conservative estimate with installation direction (7.18) of anchor displacement over long periods of sustained loading. The determination of the coefficients a and b is R10.12 While many injectable adhesives are formulated sensitive to the number of data points evaluated and should as gels with a viscosity that is suitable to permit their use in be approached with care. other than down-hole applications, the injection of adhesive and positioning of the anchor element for orientations where 10.11.1 The total displacement over the anchor intended gravity works against the installation may require special service life, which includes the initial elastic displacement techniques and equipment. Temperature extremes can also plus the creep displacement, is determined for each specimen affect the installation process, whereby hotter ambient by projecting a logarithmic trend line forward over the temperatures will simultaneously decrease the adhesive intended anchor service life. The trend line shall be determined viscosity and accelerate the curing process and colder by calculating a least-squares fit through the data points using temperatures will generally increase viscosity and retard Eq. (10-24) and shall be constructed with data from the last curing. The use of a clear polycarbonate tube to simulate 20 days, with a minimum of 20 data points, of the creep test. blind injection conditions, as shown in Fig. 10.2, can be particularly effective for establishing the effectiveness of Δ(t) = Δt=0 + at b (10-24) installation procedures, especially for deeper holes. where 10.12.1 When installed horizontally and overhead in Δ(t) = total displacement recorded in the test at time accordance with the MPII, the annular gap around the anchor element shall remain completely filled with adhesive and the t, mm; anchor element shall not displace downward more than da/20 Δt=0 = initial displacement under sustained load, mm; or 2.5 mm during the cure time. Include the following t = time corresponding to the total recorded criteria in the assessment: displacement, in hours; and 1. The adequacy of the MPII for the installation orientation being evaluated. a,b = constants evaluated by regression analysis. 2. For overhead installations, the adequacy of measures, 10.11.2 Calculate the estimated displacement corresponding as required, to prevent sag of the anchor element prior to the anchor intended service life for each test using Eq. (10-25). to adhesive cure (Fig. 10.2(a)). Δservice = Δt=0 + a(tservice)b (10-25) 3. For overhead and horizontal installations, the adequacy of measures, as required, to capture excess adhesive where during installation of the anchor element, to protect the unbonded portion of the anchor element from adhesive, Δservice = extrapolated estimate of the total displacement and to ensure that the annular gap around the anchor over the anchor intended service life, mm; element is completely filled with adhesive over the bonded length (Fig. 10.2(b) and (c)). Δt=0 = initial displacement recorded under sustained load, mm; 4. The adequacy of installation procedures to prevent formation of gaps and/or trapped air in the adhesive tservice = intended anchor service life, in hours, at 50 years along bonded length of the anchor (Fig. 10.2(d)). (standard temperature conditions) and 10 years 10.12.2 The value of αreq for the tension capacity shall (elevated temperature conditions); and be 0.90. a,b = constants evaluated by regression analysis in accordance with 10.11.1. 10.11.3 The mean values of the extrapolated estimates of the total displacement over the anchor intended service life Δservice at standard temperature and at the long-term elevated temperature shall not exceed Δlim, where Δlim is the mean displacement corresponding to loss of adhesion Nadh for adhesive anchors (10.4.4, Fig. 10.1(a) through (d)) as

48 QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY Fig. 10.2—Assessment criteria for evaluation of effectiveness 10.14—Assessment of performance with of installation procedures for overhead installations. decreased installation temperature (8.6) 10.12.3 Where testing and assessment to address sensitivity R10.14 A distinction is made for systems that are intended to installation direction in accordance with this standard is for installation at 10°C or above and those intended for not conducted, the product shall be limited to down-hole installation at temperatures below 10°C. At low tempera- installation only and the product labeling will include the tures, curing of the adhesive may be retarded to the degree notification shown in Fig. 7.2. that the bond is developed in part through freezing of the adhesive. This bond mechanism may not be reliable if the 10.13—Assessment of performance at elevated concrete temperature should rise. temperature (8.5) 10.14.1 For anchors recommended for installation in R10.13 The assessment for performance at the long- and concrete temperatures below 10°C, the mean and the 5 percent short-term elevated temperature permits a 20 percent decrease fractile of the failure loads associated with the reduced in strength for the short-term event. Short-term elevated temperature installation shall equal or exceed the mean and temperatures are those associated with diurnal cycles or other the 5 percent fractile of the corresponding reference tests. transient phenomena. Long-term elevated temperatures are Alternatively, it shall be shown that the two data sets are those that occur over extended periods of time. statistically equivalent. 10.13.1 Calculate αlt from the tension test results at the 10.14.1.1 Omit comparison of the 5 percent fractile long-term test temperature using Eq. (10-26). values if either of the following conditions are met: • For both test series, the COV of the failure loads is v αlt = min N-----l-t; N-----k--,--l-t ≤ 1.0 (10-26) No Nk, o ≤ 10%. • The difference in the number of tests in each series Δn ≤ 5 and the COV of the temperature test series is equal to or less than the COV of the reference test series. 10.14.2 For anchors recommended for installation in concrete temperatures below 5°C, the conditions of 10.14.1 shall be fulfilled. In addition, the displacement of the anchor under sustained load just prior to tension testing to failure shall stabilize to the degree that an assessment can be made that failure is unlikely to occur. 10.14.3 Retest anchors that do not fulfill the requirements for a given target temperature at a temperature at which the requirements are fulfilled. Report the temperature at which the requirements are fulfilled as the minimum concrete temperature at the time of installation. 10.15—Assessment for cure time at standard temperature (8.7) R10.15 Manufacturers usually provide cure times for a variety of temperatures, typically in the MPII. Tests for the cure time at standard temperature represent a spot check of the validity of the data provided by the manufacturer. 10.15.1 Assess the results of the tests for curing at standard temperature in accordance with Eq. (10-28). 10.13.2 Calculate αst from the tension test results at the -----N----c--u---r--e----- ; -----N----k--,--c--u---r--e----- short-term test temperature using Eq. (10-27). N c u r e +24h Nk, cure+24h min ≥ 0.9 (10-28) αst = min ----N----s--t---- ; ----N----k--,--s--t---- ≤ 1.0 (10-27) 0.8Nlt 0.8Nk, lt where 10.13.3 Omit comparison of the 5 percent fractile values if Ncure = mean tension capacity corresponding to the either of the following conditions is met: manufacturer’s published minimum cure Ncure+24h = time, N; • For both test series, the COV of the failure loads v ≤ 10%. mean tension capacity corresponding to the • The difference in the number of tests in each series Δn Nk,cure = manufacturer’s published minimum cure time plus 24 hours, N; ≤ 5 and the COV of the temperature test series is equal characteristic tension capacity corresponding to or less than the COV of the reference test series. to the manufacturer’s published minimum cure time, N; and 10.13.4 Refer to Section 10.4.4 for requirements on displacement.