Experiments to relate acoustic emission energy to fracture energy of concrete

Acoustic emission (AE) was used to measure energy associated with fracture of standard concrete test specimens. The goal of the work was to identify ways in which AE could be used to quantify damage in generic laboratory structures for the purpose of tuning damage models. A series of mortar and concrete specimens of different compositions were tested for fracture energy G(f), while simultaneously being monitored for acoustic emission energy release. Reasonable correlation between the two quantities was observed for fine-grained specimens, however the relationship was not as good for coarse-grained specimens. Toughening mechanisms such as friction are suggested as being responsible for the poor relationship observed in the course-grained materials. It is further suggested that AE energy release can be related to actual crack formation energy but not to friction and other internal energy dissipation or toughening mechanisms.