2. Compatibility of bonded materials

Compatibility between the two materials is therefore an essential condition for lasting repair. However, designers are often unfamiliar with this concept.

Engineers are only just beginning to realize that the compressive strength of concrete is not the only criterion to guide their design. If this is true in the case of a structure to be built, it is all the more true in the case of a structure to be repaired. A considerable number of repairs that deteriorate prematurely due to drying, freezing, alkali-aggregate reactions, etc. are attributable to an overemphasis on strength to the detriment of durability. Generally speaking, in the case of repairs, strength is not a determining factor, and the emphasis should instead be placed on the compatibility between the filler material and the substrate. The durability and strength of the whole is directly dependent on this...