钢纤维定向对水泥基复合材料等效断裂韧度的影响

Influence of aligned steel fiber on equivalent fracture toughness of cement based materials

通过不同钢纤维分布方向和不同钢纤维掺量的预制缺口三点弯曲梁断裂试验,研究了钢纤维定向对钢纤维增强水泥基复合材料等效断裂韧度的影响。利用试验得到的荷载-挠度曲线,分析了钢纤维对水泥基复合材料断裂性能的影响,并计算了等效断裂韧度。结果表明,定向钢纤维增强水泥基复合材料的等效断裂韧度要明显高于相同掺量的乱向钢纤维增强水泥基复合材料,且等效断裂韧度随着钢纤维掺量的增加而逐渐增大;定向钢纤维试件的临界等效裂缝长度小于相同掺量的乱向钢纤维试件,且等效裂缝长度随着钢纤维掺量的增加而逐渐减小。此外,依据裂缝断裂面处的钢纤维数量和方向效应系数两方面解释了钢纤维掺量及定向对等效断裂韧度的提高作用。

The effect of aligned steel fiber on the equivalent fracture toughness of steel fiber reinforced cement matrix composites was investigated through the fracture test of three point bend beam of prefabricated notch with different steel fiber distribution direction and different steel fiber content.The influence of steel fiber on the fracture properties of cement matrix composites is analyzed by using the load deflection curve obtained by test and the equivalent fracture toughness is calculated.The results show that the equivalent fracture toughness of aligned steel fiber reinforced cement composites are significantly higher than the same content of chaos to the steel fiber reinforced cement based composites,and equivalent fracture toughness with the increasing of the fiber content increases gradually.Directional steel fiber specimens equivalent crack length is less than the same amount of disorder steel fiber specimens,and the equivalent crack length increased with the dosage of steel fibre decreases.In addition,the effect of the content of steel fiber and aligned on the equivalent fracture toughness is explained in two aspects of the number of steel fibers and the direction effect coefficient at the fracture surface.