Dynamic compressive behaviour of basic magnesium sulfate cement–coral aggregate concrete (BMSC–CAC) after exposure to elevated temperatures: Experimental and analytical studies

Abstract

This study investigates the effects of high temperature and strain rate on the dynamic compression behaviour of basic magnesium sulfate cement–coral aggregate concrete (BMSC–CAC). Specimens are exposed to temperatures ranging from 100 °C to 900 °C and then systematically tested using a split Hopkinson pressure bar (SHPB) apparatus. A three-dimensional mesoscale modelling approach is adopted in this study to account for the random shape and position of the aggregate. Results indicate that the dynamic impact damage is due to the coupled effect of high exposure temperature and high strain rate. At lower exposure temperatures, the dynamic compressive strength is similar to that at ambient temperature. However, at exposure temperatures of 500 °C and 700 ℃, the compressive strength is reduces to 50% and 30% of that at ambient temperature, respectively. Additionally, an increase in the exposure temperature increases the strain rate and continuously decreases the elastic modulus of concrete. A dynamic constitutive model is proposed considering the temperature and strain rate as influencing factor. This mesoscale modelling method is highly reliable and provides the best calculation parameters for simulating and predicting the dynamic compressive effect of BMSC–CAC after exposure to high temperatures.