Impact of high-temperature-water cooling damage on the mechanical properties of concrete

A series of impact tests were conducted on split Hopkinson pressure bar equipment to study the influence of high-temperature-cooling damage on the mechanical properties of concrete. The experimental investigation showed the influence on the peak stress, peak strain, and fracture mode. The results indicate that the strain rate is directly related to the loading rate and heating temperature. The test results of natural cooling and water immersion cooling treatment were compared, which showed that the strength of water-cooled specimens is higher than that of naturally cooled specimens before the heating temperature reaches 400 degrees C and becomes much lower when the heating temperature is higher than 400 degrees C. Based on the experimental study, a dynamic non-linear elastic constitutive equation was established using a particle swarm optimization algorithm and an inversion analysis method. These results could provide theoretical references for the design of the ultimate strength of concrete materials for practical applications, such as fire and explosion prevention. (C) 2019 Elsevier Ltd. All rights reserved.