The three main signs of distress in a concrete structure are cracking, spalling and disintegration. To complete durable repairs, it is necessary to consider the factors affecting the design. The selection of repair systems as parts of a whole as components of a composite system. Cracking is one of the most misunderstood problems of concrete as it is generally regarded as indicative of defective design and materials. Methods of repairing cracks include bonding with epoxies, routing and sealing, stitching, external stressing, grouting, blanketing and use of overlays etc. Repairing cracks does not usually involve strengthening. In a structure showing spalling and breakup, it is usual to find that there have been substantial losses of section and pronounced corrosion of support. Hence, the repair includes some requirement for restoration of lost strength. Development of cracking in concrete is due to tensile stress and can be detained by removing these stresses. Further the cracks can be closed by inducing a compressive force, sufficient to overcome the tension and to provide a remaining compression. The success of repair and rehabilitation of a structure depends on the specific plans designed for it.
