Investigation of effects of aggregate size on the fracture behavior of high performance concrete by acoustic emission

As an important component of concrete, aggregate has a significantly influence the fracture behavior of high performance concrete. In this paper, the effects of aggregate size distribution on the fracture properties of high performance concretes with strength ranging from 50 MPa to 80 MPa were investigated under three-point-bending tests. Acoustic emission (AE) technique with three-dimensional orientation feature was applied to study the effect of maximum aggregate size (dmax) on fracture properties and the facture process zone (FPZ) at the crack tip. The results showed that the fracture energy of concrete increased with the increase of dmax. The larger the size of the aggregate, the more significant the deflection of propagating crack and the greater the FPZ can form. That AE hits had a very good relation indicating its potential to measure inner damage of concrete during cracking.