224.1R-07 Causes, Evaluation, and Repair of Cracks in ...

1 ACI , evaluation , and Repairof Cracks in concrete StructuresReported by ACI Committee 224 American concrete Institute Advancing concrete knowledgeCauses, evaluation , and Repair of Cracksin concrete StructuresFirst PrintingMarch 2007 ISBN 978-0-87031-234-2 Copyright by the American concrete Institute, Farmington Hills, MI. All rights reserved. This materialmay not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or otherdistribution and storage media, without the written consent of 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 occa-sionally find information or requirements that may be subject to more than one interpretation or may beincomplete or incorrect.

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5 Thisdocument is intended for the use of individuals who arecompetent to evaluate the significance and limitations of itscontent and recommendations and who will acceptresponsibility for the application of the material it American concrete Institute disclaims any and allresponsibility for the stated principles. The Institute shall notbe liable for any loss or damage arising to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of the contract documents, theyshall be restated in mandatory language for incorporation bythe , evaluation , and Repair of Cracksin concrete StructuresReported by ACI Committee 224 ACI causes of Cracks in concrete structures are summarized.

6 The proce-dures used to evaluate cracking in concrete and the principal techniquesfor the Repair of Cracks are presented. The key methods of crack Repair arediscussed, and guidance is provided for their proper : alkali-silica reaction; alkali-carbonate reaction; autogenoushealing; concrete ; consolidation; corrosion; cracking (fracturing); dryingshrinkage; epoxy resins; evaluation ; grouting; heat of hydration; massconcrete; methacrylates; mixture proportion; overlay; plastic; polymer;precast concrete ; prestressed concrete ; reinforced concrete ; Repair ; resins;settlement shrinkage; shrinkage; slab-on-ground; specification; thermalexpansion; volume , p.

7 1 causes and control of cracking,p. Cracking of plastic Cracking of hardened concreteChapter 2 evaluation of cracking, p. Determination of location and extent of Selection of Repair proceduresChapter 3 Methods of crack Repair , p. Epoxy Routing and Near-surface reinforcing and Additional Drilling and Gravity crack Polymer Overlay and surface Autogenous healingChapter 4 References, p. Referenced standards and Cited referencesMohamed N. Abou-ZeidFouad H. FouadRalf LeistikowRandall W. PostonJames P. Barlow*David W. FowlerPeter A. LipphardtRoyce J. RhoadsFlorian G. BarthGrant T. HalvorsenEdward G. NawyJohn W. RobertsJ. Floyd BestWill HansenKamran M.

8 NematiAndrew ScanlonDavid Darwin Harvey H. Haynes*Keith A. PashinaAndrea J. SchokkerJohn F. Duntemann*Member of task group that prepared these revisions. Chair of task group that prepared these J. Frosch*ChairJeffrey S. COMMITTEE REPORTPREFACEC racks in concrete have many causes . They may affectappearance only, or they may indicate significant structuraldistress or a lack of durability. Cracks may represent the totalextent of the damage, or they may point to problems ofgreater magnitude. Their significance depends on the type ofstructure, as well as the nature of the cracking. For example, Cracks that are acceptable for buildings may not be accept-able in water-retaining crack Repair techniques depend on knowing the causesand selecting appropriate Repair procedures that take thesecauses into account; otherwise, the Repair may only betemporary.

9 Successful long-term Repair procedures must addressthe causes of the Cracks as well as the Cracks report is intended to serve as a tool in the process ofcrack evaluation and Repair of concrete causes of Cracks in concrete are summarized alongwith the principal procedures used for crack control. Bothplastic and hardened concrete are considered. The impor-tance of design, detailing, construction procedures, concreteproportioning, and material properties are techniques and methodology for crack evaluation aredescribed. The need to determine the causes of cracking as anecessary prerequisite to Repair is emphasized. The selectionof successful Repair techniques should consider the causes ofcracking, whether the Cracks are active or dormant, and theneed for Repair .

10 Criteria for the selection of crack repairprocedures are based on the desired methods of crack Repair are presented, includingthe techniques, advantages and disadvantages, and areas ofapplication for 1 causes AND CONTROLOF IntroductionThis chapter presents a brief summary of the causes ofcracks and means for their control. Cracks are categorized asoccurring either in plastic concrete or hardened concrete (Kelly 1981; Price 1982). In addition to the informationprovided herein, further details are presented in ACI 224 Rand articles by Carlson et al. (1979), Kelly (1981), Price(1982), and Abdun-Nur (1983). Additional references arecited throughout the Cracking of plastic Plastic shrinkage cracking When moisture evapo-rates from the surface of freshly placed concrete faster thanit is replaced by bleed water, the surface concrete to the restraint provided by the concrete below thedrying surface layer, tensile stresses develop in the weak,stiffening plastic concrete .