Compressive Performance of Concrete after High Temperature Strengthened with ECC

When concrete members are exposed to fire, the compressive performance of the material will be severely reduced. To ensure the safety of the members, it is necessary to analyze the impact of high temperature on the performance of concrete members and strengthen them appropriately. ECC with remarkable tensile strain-hardening characteristics and excellent compression deformation ability is the right choice as a reinforcing material. This experiment analyzes the impact of high temperature on concrete and uses engineered cementitious composite (ECC) to strengthen the heat-damaged concrete. The influence of different conditions such as the thickness of the surface layer, the ECC’s tensile performance, the binder, the schemes of reinforcement, and the different temperatures on the reinforcement effect was compared. The test results showed that ECC can effectively improve the brittle failure characteristics of concrete after high temperature and increase the bearing capacity, ductility, and residual strength. Moreover, the reinforcement effect will improve significantly with the increase in the surface layer’s thickness. For reinforcement materials with similar compressive properties, excellent tensile properties can achieve better effects. Applying binder can delay the peeling of the layer. The surface layer is better than the diagonal reinforcement. Even if the concrete is severely damaged by high temperature, the surface layer can still effectively improve the compression performance of the heat-damaged concrete and maintain it at a high level. In summary, ECC can significantly improve the compressive performance of heat-damaged concrete.