Development of test method for cracking tendency of repair materials

摘要

Among the most serious causes of concrete repair failures is cracking in the repair. Cracking may result in the reduction of an effective cross-sectional area of the repaired structure, and always substantially increases permeability of cover to the reinforcement, which leads to the corrosion and deterioration. At present there is no reliable "yardstick" by which to judge the repair material's sensitivity to cracking. The integrity and performance testing which correlates with in situ performance does not exist. This is an area that, in the last 10 years, has seen several new and promising developments aimed at improving the ability to evaluate the cracking tendency of cementitious repair materials which influence performance and durability of concrete repair. None of these tests, methods and techniques offers a guarantee of success. Some methods have been developed to the point that they can give a close idea of materials deformability, but this is not yet at a stage at which it can be reliably applied to in situ repairs. This paper summarizes the findings of the Phase Ⅰ research study that was performed to develop a laboratory/field-reliable test method to evaluate the cracking tendency of repair materials.