Study of crack propagation in concrete under multiple loading rates by acoustic emission

It is of great importance to investigate the effect of multiple loading rates on the crack propagation of brittle material such as concrete using acoustic emission because engineering structures are subjected to multiple loading conditions. Although material behaviour under single loading mode has been extensively studied, very limited research has been conducted to investigate the performance of brittle materials subjected to varying loading conditions. This paper presents an experimental study of the effects of single and multiple strain rates on cement mortar samples using acoustic emission. A total number of 81 concrete specimens were tested, in this 28 samples were tested in constant strain rate, whereas rest 53 samples were tested in multiple loading rates. Axial strain, lateral strain and acoustic emission counts were recorded continuously until the specimens had failed. The results showed that concrete behaves differently under multiple loading rates. Acoustic emission was in close agreement with the crack propagation and damage of concrete samples.