【摘要】 通过混杂钢纤维二级配混凝土的三点切口梁断裂试验,研究不同钢纤维体积掺量(0.5%,0.8%,1.0%,1.2%)、不同钢纤维长度(30mm,60mm)混杂使用以及水灰比对钢纤维二级配混凝土的P-CMOD曲线、起裂韧度、失稳韧度和断裂能的影响,并基于损伤力学理论,建立混杂钢纤维混凝土断裂损伤弯拉应力-应变关系。结果表明:掺入钢纤维的二级配混凝土相比于基体混凝土延性更好;不同长度钢纤维混杂使用对二级配混凝土的断裂韧度和断裂能有不同影响,试验范围内,钢纤维二级配混凝土断裂韧度提升最佳的优化组合为钢纤维掺量1.2%、长纤维占比50%、水灰比0.58;断裂能提升最佳的优化组合为钢纤维掺量1.2%、长纤维占比65%、水灰比0.33;文中建立的混杂钢纤维二级配混凝土弯拉应力-应变模型与试验结果吻合较好。更多还原

【Abstract】 The fracture performance of three-point notched beams of two-grade aggregate concrete reinforced by hybrid steel fiber were tested.The effects of steel fiber volume contents(0.5%, 0.8%, 1% and 1.2%), the lengths of steel fiber(30 mm, 60 mm) and the water-cement ratio on the fracture properties were studied, including P-CMOD curves, fracture toughness, instability of toughness and fracture energy.The stress-strain relationship for fracture damage of hybrid steel fiber reinforced concrete was proposed based on the damage mechanics theory.The results show that concrete mixed with steel fiber has better ductility than the ordinary concrete.The mixed use of steel fibers with different lengths has effects on the fracture toughness and fracture energy of two-grade aggregate concrete.The optimal combination of concrete with better fracture toughness is suggested as steel fiber mixing amount of 1.2%, long fiber proportion of 50% and water-cement ratio of 0.58.The fracture energy can be greatly improved by a desired combination proportion of 1.2% steel fiber mixing amount, 65% long fiber proportion and 0.33 water-cement ratio.The stress-strain model established in this paper is in good agreement with the experimental results.更多还原