新型棒状聚丙烯纤维混凝土抗剪性能试验与比较

Experiment and Comparison on Shear Behavior of New Type Rodlike Polypropylene Fiber Reinforced Concrete

摘要:

针对最新引进日产棒状聚丙烯纤维和喷射混凝土衬砌中常用的钢纤维,通过18组72个混凝土试样的双面剪切试验,研究了不同基体强度、不同纤维掺量混凝土抗剪强度变化特性.试验结果表明:①棒状聚丙烯纤维混凝土抗剪强度随着纤维掺量增加呈现先增大后减小的趋势,钢纤维混凝土抗剪强度随着纤维掺量增加而增大; ②纤维掺量在0.5%以内,棒状聚丙烯纤维混凝土抗剪强度增大幅度接近钢纤维混凝土,纤维掺量在0.5%以上,棒状聚丙烯纤维混凝土抗剪强度增大幅度低于钢纤维混凝土; ③两种纤维对C30混凝土抗剪强度的改善一般比C50混凝土大.最后,基于回归分析理论得到纤维混凝土抗剪强度拟合计算公式,公式计算结果与试验结果比较一致.

Abstract:

Aiming at the rodlike polypropylene fiber introduced from Japan and common steel fiber used in the shotcrete lining,this paper presents a study on changes of the shear strength of concrete with different matrix strength and fiber content through the shear test of 72 specimens divided into 18 groups.The results show that as the fibre content increases,the shear strength of the rodlike polypropylene fiber concrete increases at first and then drops down,while the shear strength of the steel fiber concrete increases.When the fibre content is within 0.5%,the shear strength increase of the rodlike polypropylene fiber concrete is close to that of the steel fiber concrete,when the fibre content exceeds 0.5%,the shear strength increase of the rodlike polypropylene fiber concrete is lower than that of the steel fiber concrete.The fibers improve more on the shear strength of the C30 concrete than the C50 concrete.Finally,fitting formulas on the shear strength of the fiber concrete are gained based on the theory of regression analysis,and the calculation results of the formulas are accordant with the experimental results well.