PREFACECracks in concrete have many causes. They may affect appearance only@ or they may indicate significant structural distress or a lack of durability. Cracks may represent the total extent of the damage@ or they may point to problems of greater magnitude. Their significance depends on the type of structure@ as well as the nature of the cracking. For example@ cracks that are acceptable for buildings may not be acceptable in water-retaining structures.The proper repair of cracks depends on knowing the causes and selecting the repair procedures that take these causes into account; otherwise@ the repair may only be temporary. Successful long-term repair procedures must attack the causes of the cracks as well as the cracks themselves.To aid the practitioner in pinpointing the best solution to a cracking problem@ this report discusses the causes@ evaluation procedures@ and methods of repair of cracks in concrete. Chapter 1 presents a summary of the causes of cracks and is designed to provide background for the evaluation of cracks. Chapter 2 describes evaluation techniques and criteria. Chapter 3 describes the methods of crack repair and includes a discussion of a number of techniques that are available. Many situations will require a combination of methods to fully correct the problem.