The double-K fracture toughness and fracture energy of high-strength concrete and hybrid-steel fiber reinforced high-strength concrete were calculated employing standard compacted tension（CT） formula and wedge splitting（WS） formula by wedge splitting test.By comparing two formulas,it is found that the unstable fracture toughness calculated by CT formula is 0.85 to 0.87 times of that calculated by WS formula,and adopting standard CT specimen can gain the exact test results by WS test with the specimen satisfying the size requirement for CT.The influences of fiber type,fiber length and fiber volume ratio on reinforced effect to concrete were analyzed.With the strength increasing,the fracture toughness and fracture energy both increase.In addition,it is proposed that the double-K fracture toughness is better to be used as the ductility evaluation criterion of high-strength concrete and fracture energy is better to be used as the ductility evaluation criterion of hybrid-steel fiber reinforced high-strength concrete.%采用楔入劈拉试验方法,利用标准紧凑拉伸公式与楔入劈拉经验公式分别计算高强混凝土及混杂钢纤维高强混凝土的双K断裂韧度和断裂能,经比较发现用紧凑拉伸公式计算的失稳断裂韧度值是经验公式的0.85～0.87倍,因此建议采用尺寸符合标准紧凑拉伸要求的试件进行试验确定断裂韧度.分析了纤维混杂后纤维类型、纤维长度、纤维掺量对混凝土增强、增韧的影响,试验结果表明随着混凝土强度增加,断裂韧度、断裂能增大.最后建议高强混凝土采用双K断裂韧度作为韧性评价指标,高强钢纤维混凝土采用断裂能作为韧性评价指标.
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