三点弯曲下PVA-尾矿砂水泥基复合材料断裂特性

针对混凝土的早期开裂问题,设计了PVA-尾矿砂水泥基复合材料三点弯曲梁试验,研究了尾矿砂掺量、缝高比、纤维掺量以及使用条件对断裂韧度和断裂能的影响规律.通过试验得出P-δ曲线和P-COM D曲线,并计算断裂韧度和断裂能.结果表明:断裂韧度与缝高比成反比,且随着纤维掺量的增加而增加,但尾矿砂对断裂韧度的影响却很小;断裂能随纤维掺量的增加而增加,随尾矿砂掺量的增加而降低;正常使用条件下的断裂能、断裂韧度计算值比腐蚀使用条件下的断裂能、断裂韧度计算值均增大约10%.

Fracture characteristics of PVA reinforced tailing sand cementitious composite under three point bending

In order to solve the early-stage cracking problem of concrete, the three point bending beam test of PVA reinforced tailing sand cementitious composite was designed. The influence of tailing sand content, crack depth ratio, fiber content and working conditions on the fracture toughness and fracture energy was studied. The fracture toughness and fracture energy were calculated through the P-δ curves and P-COMD curves obtained from the test. The results show that the fracture toughness is inversely proportional to the crack-depth ratio, and increases with increasing the fiber content, but the tailing sand content has little effect on the fracture toughness. The fracture energy increases with increasing the fiber content, while decreases with increasing the tailing sand content. Under the normal working condition, the calculated values of both fracture energy and fracture toughness are 10% larger than those obtained under the corrosion working condition.