Dynamic Compressive Behavior of 10-Year-Old Concrete Cores after Exposure to High Temperatures

Abstract

In fires, concrete structures sometimes suffer blasting loads. This paper investigated the effect of high temperature on the dynamic mechanical properties of concrete. The specimens were cored from 10-year-old concrete beams and exposed to room temperature (20°C), 200°C, 400°C, and 600°C. The split Hopkinson pressure bar (SHPB) was used to study the dynamic mechanical behavior. The results showed that the dynamic compressive stress–strain curve of concrete after exposure to high temperature can be divided into three stages: elastic growth, slow decline, and rapid decline. Furthermore, at the same temperature, as the strain rate increased, the dynamic strength increased. When the strain rate was constant, high temperature resulted in low dynamic strength. A dynamic constitutive model is proposed. The calculation results were in good agreement with the experimental data. Therefore, this model can provide a theoretical basis for the simulation of the dynamic mechanical behavior of concrete after exposure to high temperature.