Mechanical properties and damage mechanisms of concrete under four temperature gradients combined with acoustic emission method

Abstract

This study aims to better understand the mechanical properties and damage mechanisms of concrete under different temperature gradients. Four kinds of temperature gradients, namely 40-4 °C,60-4 °C, 80-4 °C, and 100-4 °C, were set by a self-developed temperature conduction device. The strength, peak strain, and failure characteristics of concrete under four temperature gradients were studied. The damage mechanisms of concrete were further revealed by the ringing counts and b value of acoustic emission (AE). The results showed that the strength of concrete rapidly decreased while temperature increased and the peak strain increased. With the increase of temperature gradients, the failure characteristics of concrete gradually change from brittle to ductile. A sudden increase in the ringing counts of AE can be used as the criterion for aggravation of concrete damage. During the loading process, a decrease in the b value can be used as the criterion of concrete failure under temperature gradients., indicating the formation of macroscopic cracks.