MESO-SCALE SIMULATIONS OF DYNAMIC COMPRESSIVE BEHAVIOR OF CONCRETE AT ELEVATED TEMPERATURE

A meso-scale numerical analysis model of concrete which studies the dynamic compression damage behavior and the strain rate effect at elevated temperature was established, which is combined with the meso-scale heterogeneity of concrete and considers the mechanical property degradation effect and the strain rate effect of micro-components at elevated temperature. In this approach, the heat conduction behavior was simulated initially, then the "result output" was used as "initial conditions", and the dynamic compressive behavior of concrete was conducted. The good agreement between the numerical simulation results and the experimental results indicates the feasibility and the reasonableness of the presented meso-scale approach. Subsequently, the dynamic uniaxial compression damage behavior and failure mechanism on the meso-scale of concrete at elevated temperature were studied. The influence regularity of high temperature on the dynamic compressive strength increase coefficient (CDIF) was revealed. The results indicate that the damage of concrete concentrates on the loading terminal with weak mechanical properties at elevated temperature. Furthermore, the temperature degradation effect on mechanical properties of concrete (such as strength and secant modulus) is more significant compared with the strain rate effect.