ACI 548.11R-12
Guide for the Application of Epoxy and Latex Adhesives for Bonding Freshly Mixed and Hardened Concretes
Reported by ACI Committee 548
First Printing September 2012
Guide for the Application of Epoxy and Latex Adhesives for Bonding Freshly Mixed and Hardened Concretes 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 consequential 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.
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ACI 548.11R-12 Guide for the Application of Epoxy and Latex Adhesives for Bonding Freshly Mixed and Hardened Concretes Reported by ACI Committee 548 Bradley Nemunaitis, Chair
Ashraf I. Ahmed Mohammad A. Alhassan Milton D. Anderson Jacques A. Bertrand Constantin Bodea Timothy Bower David W. Fowler Robert W. Gaul Quentin L. Hibben Albert O. Kaeding John R. Milliron Myles A. Murray Joseph A. Nuciforo, Jr. John R. Robinson
Mahmoud M. Reda Taha, Secretary
Donald A. Schmidt Raymond J. Schutz Qizhong Sheng Joe Solomon Michael M. Sprinkel Michael S. Stenko Donald P. Tragianese Wafeek S. Wahby David White David P. Whitney Richard E. Wollmershauser
Craig A. Ballinger John J. Bartholomew Shashi P. Bhatnagar Zhi-Yuan Chen Inz Lech Czarnecki Harold (Dan) R. Edwards Larry J. Farrell Jack J. Fontana George Horeczko David P. Hu Bert Paul Kreikemans Deon Kruger William Lee Troy D. Madeley
Consulting Members Lu Anqi
Henry N. Marsh, Jr. Peter Mendis Peter J. Moss Yoshihiko Ohama Kelly M. Page Jerzy Pictrzykowski Richard C. Prusinski Hamid Saadatmanesh Donald A. Schmidt Meyer Steinberg Harold H. Weber, Jr.
CONTENTS
This guide provides information, requirements, and procedures for bonding freshly mixed and hardened concretes by using epoxy or latex adhesives. This guide covers evaluation of hardened concrete, selection of suitable epoxy or latex adhesive and application methods.
Chapter 1—Scope, p. 2
Keywords: adhesives; bonding; epoxy adhesives; evaluation; latex adhesive; preparation.
Chapter 3—Hardened concrete evaluation, p. 2
Chapter 2—Definitions, p. 2
Chapter 4—Removal of unsound concrete, p. 2 Chapter 5—Surface preparation, p. 2 Chapter 6—Use of epoxy adhesives, p. 3 6.1—Selection of epoxy adhesive 6.2—Mixing of epoxy adhesive 6.3—Application of epoxy adhesive
ACI Committee Reports, Guides, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. This document is 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. The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom. Reference to this document shall not be made in contract documents. If items found in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.
ACI 548.11R-12 supsersedes ACI 503.6R-97(03) and became effective September 6, 2012. Copyright © 2012, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.
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APPLICATION OF EPOXY AND LATEX ADHESIVES FOR BONDING (ACI 548.11R-12)
Chapter 7—Use of latex adhesives, p. 3 7.1—Selection of latex adhesive 7.2—Application of latex adhesive Chapter 8—References, p. 4 CHAPTER 1—SCOPE This guide provides information, requirements, and procedures for bonding freshly mixed and hardened concretes by using epoxy or latex adhesives. This information will be of particular use to contractors. This guide consists of: a) Evaluation of hardened concrete to determine proper preparation and surface conditioning before application of adhesives b) Selection of suitable epoxy or latex adhesive depending on the expected performance and environmental conditions (ACI 503.5R) c) Application methods CHAPTER 2—DEFINITONS 2.1—Definitions ACI provides a comprehensive list of definitions through an online resource, “ACI Concrete Terminology,” http:// terminology.concrete.org. CHAPTER 3—HARDENED CONCRETE EVALUATION Contaminated and deteriorated concrete can be detected by visual inspection; however, in many cases, visual determination of the soundness of the concrete is not sufficient to select the repair and preparation methods. It is necessary to determine the extent and cause of deterioration, and if that cause is active. For guidance on surveys for these determinations, refer to ACI 201.1R, ACI 364.1R, and ASTM C823/C823M. Methods common for evaluating and determining concrete condition include sounding with a hammer or chain drag, ultrasonic pulse velocity, petrographic analysis, infrared thermography, radar detection, core evaluation, impact echo, measurement of chloride ion content, and bond tests as described in ACI 228.1R and ASTM C1583/C1583. Proper preparation, as described in Chapter 5, of any concrete to receive an adhesive is of primary importance. Inadequate preparation may result in bond failure at the adhesive interface. The surface conditions required for different types of adhesive are described in Chapters 4 and 5. CHAPTER 4—REMOVAL OF UNSOUND CONCRETE The removal of unsound or damaged concrete prior to placing an adhesive and before placement of the freshly mixed concrete is a necessary part of the rehabilitation of structures. The first step involves saw cutting the periphery of the removal area to a depth of 1 in. (25 mm) or to a lesser depth
necessary to clear the reinforcing steel (VDOT 2007). This saw cutting delineates the repair area and reduces edge spalling and weakness introduced by outlining the area using other methods. Saw cutting also provides a shoulder against which the repair materials can be placed and finished, resulting in a neater appearance. The saw-cut line should be located outside of the determined limits of the defect to ensure that all defective concrete is removed and that the fresh material is bonded to sound concrete. Several types of systems are available to remove unsound concrete. a) Scabblers or bush hammers are tools with several points that remove concrete by pulverizing or fracturing the surface b) Scarifiers have wheels with several points that are tipped with carbide, tungsten, or diamonds. This equipment removes concrete by scraping or impacting the surface c) Water blasting (hydrodemolition) removes concrete by projecting jets of potable water d) Jackhammers remove concrete by impacting the surface CHAPTER 5—SURFACE PREPARATION After the concrete has been removed by one or more of the aforementioned methods (USACE 1995), except for water blasting, all newly exposed surfaces should be abrasive blasted and washed thoroughly with a water jet that has a pressure of at least 1500 psi (10 MPa). The surface should then be dried with oil-free compressed air or vacuumed to remove any residual debris. Surfaces or parts of surfaces not requiring removal of concrete should be cleaned to remove all surface contaminants detrimental to the bond of the adhesive. Such contaminants may include laitance, curing membranes, surface coatings, treatments, oil, grease, rust stains, and dust. These methods are commonly used to remove contaminants a) Shot blasting, which projects metal balls of varying size at high velocity to impact and abrade the surface b) Abrasive blasting, which projects particles of varying size to impact and abrade the surface. The particles may be carried by air or water c) Scabbling, which uses bush hammers d) Scarification e) Water blasting One or more of these methods may be required for preparation. For guidance, refer to ASTM D4258 and D4259 and ICRI No. 310.1R, No. 310.2R, and No. 310.3R. Regardless of surface preparation method, the results should be such that the surface is abraded to expose the coarse aggregate in the surface with a maximum surface texture of 0.01 in. (0.254 mm) measured in accordance with ASTM E965. Heavier textures require the use of excessive adhesive. To determine if surface preparation is adequate for bonding, test for pulloff strength in accordance with ASTM C1583/C1583. If 250 psi (1.7 MPa) is achieved, then the surface preparation and concrete quality is adequate. If the pullout value is less than 250 psi (1.7 MPa) and 50 percent or more of the failure area is in the concrete at a depth of 0.236 in. (6 mm) or greater, then the surface preparation
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APPLICATION OF EPOXY AND LATEX ADHESIVES FOR BONDING (ACI 548.11R-12)
is adequate, but the concrete quality may not be adequate. In this case, an additional evaluation in accordance with Chapter 3 may be necessary. CHAPTER 6—USE OF EPOXY ADHESIVES To ensure adequate bonding using epoxy adhesives, the following requirements should be met. a) The concrete surface should be strong, dense, and sound as determined by the methods in Chapter 5. b) The concrete surface should be clean and free from contaminants and prepared as described in Chapter 5. c) In addition to other considerations, the selection of epoxy adhesive should consider the anticipated ambient and concrete temperatures. The ease of use and final properties of epoxy application are influenced by the surface temperature. Refer to ASTM C881/C881M for a list of epoxies for use at different temperatures. d) Surface moisture and vapor can interfere with the bond of the adhesive. Surface moisture and vapor leaving the concrete surface should be recognized as potential impediments to proper bond. Efforts should be made to dry the surface. Moisture vapor transmission may be detected by covering the surface tightly with a 4 x 4 ft (1.2 x 1.2 m) transparent plastic film, following the procedure in ASTM D4263. If moisture has not accumulated under the film after 6 to 8 hours, or within the time required for the adhesive to cure and the concrete to set, capillary moisture or out-gassing vapors are insufficient to adversely affect the bond. The exposure time should be extended 50 percent under the film if temperatures are below 40°F (4°C) or if the site is under cloud cover. 6.1—Selection of epoxy adhesive The epoxy adhesive should meet the requirements of ASTM C881/C881M, Type II and V, Grade 2 and 3, Class A, B, or C. In addition, unless otherwise recommended by the adhesive manufacturer, apply sufficient adhesive to cover the entire prepared surface without leaving excessive adhesive in the low areas. Apply adhesive to horizontal, vertical, and overhead surfaces prior to placing the freshly mixed concrete. Type II adhesives are used in non-load-bearing applications, whereas Type V are for load-bearing uses. Grade 1 materials are low viscosity. Grade 2 materials are medium viscosity. Grade 3 materials have a nonsagging consistency. Class A materials are used when temperatures are below 40°F (4°C), Class B materials are used when temperatures are typically between 40 and 60°F (4 and 16°C), and Class C materials are used when temperatures are above 60°F (16°C) with upper limits set by the manufacturer. 6.2—Mixing of epoxy adhesive Epoxy adhesives are supplied as two-part systems. One part contains the epoxy resin and the other part contains the hardener or curing agent. Epoxy and substrate temperatures directly affect the performance of the epoxy compound. The quantity and temperature of the adhesive at time of mixing influence the
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working time. Elevated temperatures reduce the viscosity of the epoxy. This makes it easier to mix and apply and shortens the working time in the container. Less open time before early polymerization affects the bonding ability of the epoxy compound. Cooler temperatures increase the viscosity of the epoxy. This makes thorough mixing difficult, lengthens the working time in the container, and extends the open time before concrete placement. The quantity of adhesive to be mixed should not exceed the amount that can be readily applied within the pot life or working time of the specific adhesive. For best results, condition the components from 65 to 85°F (18 to 29°C) or as recommended by the manufacturer. Before mixing, premix each component separately. Mechanical mixing of the two components is necessary, except for mixing volumes of less than 1 qt (1 L). A mixing container should have a flat bottom and a capacity approximately two times the batch size. Dry, clean, plastic pails are suitable because the sides can be scraped during mixing, allowing for easy clean up. A cage or propeller-type mixing paddle driven by a low-speed electric or air-powered drill is recommended for mixing. Mixing may take 3 to 5 minutes. Thorough mixing of both components provides optimum results. Preportioned or prepackaged units are usually supplied by the manufacturer so that the entire contents of both containers are mixed together. If smaller quantities are required, the specific proportioning ratio should be accurately measured by mass or volume. For large volumes of mixed adhesive, automatic metering and mixing equipment that dispense the properly proportioned and mixed material is recommended. Such mixers are available commercially. Mixed adhesive is applied to the repair area through a spray gun or extruding nozzle. 6.3—Application of epoxy adhesive The adhesive can be applied to the properly prepared surface using brushes, rollers, squeegees, or spray equipment. Use stiff bristle brushes in a scrubbing motion to ensure all surface irregularities and pores are coated. Epoxy adhesive provides satisfactory adhesion if the freshly mixed concrete is placed 5 to 10 minutes after applying the adhesive. This is to allow the adhesive to wet the existing surface before contact with the freshly mixed concrete. The freshly mixed concrete should be placed while the adhesive is tacky. If the epoxy bond coat has reached a tack-free stage before placement of the freshly mixed concrete, a second coat of the bonding epoxy should be applied before placement of the freshly mixed concrete. If more than 5 hours elapse, the semicured or cured epoxy should be brush blasted to provide a bondable surface for the second coat of epoxy. CHAPTER 7—USE OF LATEX ADHESIVES To ensure adequate bonding using latex adhesives, the following requirements should be met. a) The concrete surface should be strong, dense, and sound as determined by methods in Chapter 3.
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APPLICATION OF EPOXY AND LATEX ADHESIVES FOR BONDING (ACI 548.11R-12)
b) The concrete surface should be clean and free from such contaminants as described in Chapter 5. c) Latex adhesives need to be applied to a damp surface to ensure adequate wetting. The moisture content should be such that newspaper should become damp when placed on the surface. The newspaper should be removed before placing the latex adhesive. 7.1—Selection of latex adhesive Type I latex adhesives are redispersible, one-component systems used as supplied. They are restricted for interior work not subject to water immersion or relative humidity greater than 90 percent. Typically, Type I latex adhesives are vinyl acetate homopolymers or copolymers, with the comonomer being ethylene or an acrylic ester. The vinyl acetate homopolymers may be plasticized. Type II latex adhesives are nonredispersible and may be mixed with hydraulic cements. They are suitable for interior and exterior work and may be used in areas subject to water immersion or high humidity. Typically, they are styrene-butadiene copolymers or acrylic ester copolymers with a solids content of approximately 50 percent by weight. Latex-to-cement ratios are typically one-to-one by volume or one-to-two by mass. The pot life of two-part adhesives is 10 to 120 minutes. Pot life depends on the type of hydraulic cement and environmental conditions such as temperature and relative humidity. For information on Type I and Type II latex adhesives, refer to ASTM C1059/C1059M. 7.2—Application of latex adhesive Type I latex adhesives, stabilized with polyvinyl alcohol, are not suited for spray application and should be applied by brush or roller. Type II latex adhesives are applied by brushing, rolling, or spraying. The prepared surface of the hardened concrete should be dampened before application of the adhesive to ensure good contact. Typical rates of application are 200 ft2/gal. (5 m2/L) for Type I adhesives and 55 ft2/gal. (1.4 m2/L) for Type II adhesives. Follow the manufacturer’s recommendations for rate of application. For Type II adhesives, it is essential that the freshly mixed concrete is applied before the adhesive has dried or set up. If the Type II adhesive has dried or set up, the adhesive should be removed and the surface should be prepared to meet the conditions described in Chapter 7 (a, b, and c). Because Type I adhesives are redispersible, timing the application of the freshly mixed concrete is not critical, but it should be placed before the adhesive becomes contaminated. If such contamination occurs, the surface should be cleaned by wet brushing or water spray and the Type I adhesive reapplied.
CHAPTER 8—REFERENCES 8.1—Referenced standards and reports Committee documents are listed first by document number and year of publication followed by authored documents. American Concrete Institute ACI 201.1R-08—Guide for Conducting a Visual Inspection of Concrete in Service ACI 228.1R-03—In-Place Methods to Estimate Concrete Strength ACI 364.1R-07—Guide for Evaluation of Concrete Structures before Rehabilitation ACI 503.5R-92—Guide for the Selection of Polymer Adhesives with Concrete (Reapproved 2003) ASTM International ASTM C823/C823M-12—Standard Practice for Examination and Sampling of Hardened Concrete in Constructions ASTM C881/C881M-10—Standard Specification for Epoxy-Resin-Base Bonding Systems for Concrete ASTM C1059/C1059M-99(2008)—Standard Specification for Latex Agents for Bonding Fresh to Hardened Concrete ASTM C1583/C1583-04—Standard Test Method for Tensile Strength of Concrete Surfaces and the Bond Strength or Tensile Strength of Concrete Repair and Overlay Materials by Direct Tension (Pull-off Method) ASTM D4258-05(2012)—Standard Practice for Surface Cleaning Concrete for Coating ASTM D4259-88(2012)—Standard Practice for Abrading Concrete ASTM D4263-83(2012)—Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method ASTM E965-95(2006)—Standard Test Method for Measuring Pavement Macrotexture Depth Using a Volumetric Technique International Concrete Repair Institute 310.1R-1997—Guide for Surface Preparation for the Repair of Deteriorated Concrete Resulting from Reinforcing Steel Corrosion (formerly No. 03730) 310.2R-1997—Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings, and Polymer Overlays (formerly No. 03732) 310.3R-2004—Guide for the Preparation of Concrete Surfaces Using Hydrodemolition Methods USACE, 1995, Evaluation and Repair of Concrete Structures, EM 1110-2-2002, United States Army Corps of Engineers, Washington, DC, 185 pp. VDOT, 2007, Road and Bridge Specifications, Section 412.03, Virginia Department of Transportation, Richmond, VA.
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Guide for the Application of Epoxy and Latex Adhesives for Bonding Freshly Mixed and Hardened Concretes
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