Experimental study on the effect of aggregate content on fracture behavior of concrete

Effect of aggregate content on fracture behavior of concrete is studied by testing on 48 geometrically similar three-point bend concrete beams. The results are analyzed by using a size effect method, in which the fracture behavior of concrete is characterized by two parameters: fracture energy G_f and effective fracture process zone c_f. Test results showed that with increasing volume fraction of aggregate in the range 45-75%: (1) the compressive strength of concrete decreases slightly (15%), and can be practically considered to be a constant; (2) fracture energy G_f varies within 25%, and there is not critical volume fraction which gives the maximum G_f; and (3) the size of the fracture process zone decreases, which may be explained by the change in coarseness of grain structures defined in terms of mosaic patterns.