【摘要】 为了分析钢纤维混凝土的断裂机理并评估其抗裂性能，开展三点弯曲断裂试验，对比分析不同纤维长度与不同纤维掺量的钢纤维混凝土的断裂性能。采用数字图形相关法观测试验过程中试件加载点位移、裂缝口张开位移以及韧带区域不同位置的裂缝张开位移，并计算钢纤维混凝土的断裂能、起裂断裂韧度与失稳断裂韧度。结果表明：随着钢纤维长度增加，断裂能呈现出近似线性增长的趋势；随钢纤维体积掺量增加，断裂能呈现先增长后降低的趋势，并且在纤维体积掺量为1.0%时，断裂能达到最大值。掺入钢纤维后，混凝土起裂断裂韧度小幅度提高，混凝土失稳断裂韧度显著提高，并且失稳断裂韧度随着纤维长度与纤维体积掺量的增加逐渐提高。更多还原

【Abstract】 In order to further analyze the fracture mechanism of steel fiber reinforced concrete and assess its fracture resistance, the three-point bending fracture test was carried out to analyze the fracture properties of steel fiber reinforced concrete with different fiber lengths and different fiber parameters. The loading point displacement, crack mouth opening displacement and crack opening displacement along the ligament were observed by digital image correlation method. The fracture energy, initial fracture toughness and unstable fracture toughness of steel fiber reinforced concrete were calculated. The results show that the fracture energy increases approximately linearly with the increase of steel fiber length. With the increase of steel fiber volume content, the fracture energy firstly increases and then decreases, and when the fiber volume content is 1.0%, the fracture energy reaches the maximum value. By adding the steel fiber, the initial fracture toughness of concrete improved slightly, whereas the unstable fracture toughness of concrete is also significantly increased.更多还原