Analysis of Compatibility between Repair Material and Substrate Concrete Using Simple Beam with Third Point Loading

Abstract

Due to the availability of a wide variety of repair materials in the industry with a wide range of physical and mechanical properties, it is important to determine the compatibility of a repair material with the substrate concrete. In this paper, the writers investigate the compatibility between selected cementitious repair materials and a substrate concrete using a modified ASTM C 78 test procedure. The flexural strength and load-deflection curves of composite beams prepared with substrate concrete and repair materials were compared to the results from the substrate beam to assess the compatibility. In addition, the influence of three different types of curing conditions was evaluated on the compatibility between the repair materials and substrate concrete. Compressive strength, flexural strength, split tensile strength, and drying shrinkage of the repair materials and substrate concrete were individually measured to aid in the analysis of compatibility between repair and substrate materials. It was observed that not only did significant differences in strength between the repair material and substrate concrete cause incompatible failures, but high drying shrinkage of the repair materials was also found to cause incompatible failure. These findings validate previous research findings.