Quantitative evaluation of fracture processes in concrete using signal-based acoustic emission techniques

Acoustic emission (AE) techniques can be used for the investigation of local damage in materials. Compared to other observation techniques one advantage is the recording of the damage process during the entire load history without any disturbance to the specimen. This is somehow unique and permits for high-resolution studies of the time-dependent failure of materials including precise determinations of the beginning of fractures and their consecutive progression. There are only a few other experimental techniques in fracture mechanics allowing for similar detailed observations of materials' time and spatial behaviour. Moreover, these techniques allow a calibration of experiment and simulation comparing for example the output of finite element modelling with AE data analysis. This paper deals with some experimental results obtained during fracture mechanical experiments at concrete specimens demonstrating the capabilities of quantitative AE techniques.