Damage analysis in steel fibre reinforced concrete under monotonic and cyclic bending by means of acoustic emission monitoring

This paper reports on the monotonic and cyclic bending behaviour and damage evolution of steel fibre reinforced concrete (SFRC), by three-point bending tests assessed with acoustic emission (AE) monitoring. Hooked-end fibres are used with 0.25 or 0.5 V% and monotonic, progressive cyclic and variable cyclic loading are applied. The aim is to evaluate AE analysis methods for both monotonic and cyclic behaviour, and to assess the cyclic damage development by combined AE parameters and mechanical testing characteristics. The research shows the agreement between monotonic envelope and cyclic stress-CMOD curves. Furthermore, AE monitoring proves to be complementary to mechanical testing for evaluating damage accumulation in SFRC under bending. Experimental laws between damage evolution and AE activity are determined for different material types and compared to literature data. The relation between damage indicators and AE events indicates the occurrence of fatigue damage development for multiple load cycles at high load limits.