Micro–macro fracture relationships and acoustic emissions in concrete

Abstract

In this work we are interested in how micromechanical phenomena affect bulk mechanical properties. Specifically we are interested in microfracture characteristics and how they influence damage evolution and fracture toughness. Toward this end, quantitative acoustic emission techniques were used to measure microfracture properties in an array of cement-based materials of varying microstructure. Microcracks were modeled using a seismic moment tensor, which could be estimated through deconvolution of the measured acoustic emission waveforms. Results of the experiments indicate that materials with higher bulk fracture toughness had larger numbers of sliding mode microcracks, while materials with lower bulk fracture toughness had fewer numbers of tensile mode microcracks.