Acoustic emission properties of tensile fractures under different load patterns

Under different load patterns, some experiments using special mortar specimen are carried out. The whole process of initiation, cracking, growth and fracture of cracks is analyzed by using acoustic emission (AE) technique. Experimental results show that the AE properties of tensile fractures are different under loading types. The AE properties of crack propagation process under bending action contain four stages: gradual increase, quick increase, sudden increase and gradual decrease of AE numbers. But those under splitting load, it contains three stages: slow increase, sudden increase and stable increase of AE numbers. The AE characters of crack initiation and coalescences under bending are obvious, but not clear under splitting load. It deserved to further study the AE properties under different loading conditions.