Development of a Crack-Resistant Rubber-Modified Cementitious Repair Material

摘要

Failures observed on repaired concrete structures often correspond to either one of the following two modes: cracking in the repair material layer and/or delaminating at the interface due to stresses induced by differential shrinkage between repair and concrete substrate, followed in many instances by corrosion of reinforcing steel, more extensive cracking and delamination, and spalling. Numerous measures have been taken over the years to improve durability and service life of concrete repairs, but very few have targeted one of the root causes of the problem-the inherent brittleness and low deformability of cementitious materials. The approach taken in the development and practical application of the repair material described in this article deviates from the current emphasis on high-strength, high-density, low-bulk permeability materials, being instead directed toward balancing strength, ductility, and compatibility with the existing concrete substrate. Such an approach is desirable in the development of cementitious materials for repair applications with minimum maintenance and extended serviceability between repair cycles.