Abstract:In order to study the effect of sand rate on the fracture properties of recycled concrete, recycled concrete was prepared based on RC25, and recycled concrete beam specimens with sand ratios of 25%, 30%, 35%, 40%, 45% and 50% were produced. Through the three-point bending test of the beam, the variation of the fracture performance of the brick-rich recycled concrete with the sand ratio was studied from the aspects of fracture toughness and fracture energy. The results show that the fracture toughness and fracture energy of the brick-recycled concrete increase first and then decrease with the increase of sand rate. When the sand rate increases from 25% to 35%, the fracture toughness increases. By 8.43%, the fracture energy increases by 10.73%, and when the sand ratio increases from 35% to 50%, the fracture toughness decreases by 3.81%, the fracture energy decreases by 11.29%. The fracture toughness at a sand ratio less than 35% is more susceptible to changes in sand rate compared with that at a sand ratio greater than 35%, which does not happen to the fracture energy.