聚丙烯-钢纤维/混凝土柱大偏心受压承载力计算

对270个聚丙烯纤维掺量(体积分数)分别为0vol%、0.1vol%、0.2vol%、0.3vol%、0.4vol%、0.5vol%、钢纤维掺量(体积分数)分别为0vol%、0.5vol%、1vol%、1.5vol%、2vol%的聚丙烯-钢纤维/混凝土试块进行立方体抗压试验、轴心抗压试验和劈裂抗拉试验，基于复合材料力学理论，考虑纤维的取向系数、长度有效系数和界面黏结系数，对其建立强度预测模型并进行机制分析，同时选取掺量分别为0vol%、0.1vol%、0.3vol%的聚丙烯纤维、掺量分别为0vol%、1.5vol%的钢纤维制作6根聚丙烯-钢纤维/混凝土柱，对其进行大偏心受压试验，在强度预测模型的基础上进行承载力计算，提出聚丙烯-钢纤维/混凝土承载力计算方法。结果表明:钢纤维对聚丙烯-钢纤维/混凝土立方体抗压强度、轴心抗压强度和劈裂抗拉强度均有提高；聚丙烯纤维可提高聚丙烯-钢纤维/混凝土的劈裂抗拉强度，但不能提高聚丙烯-钢纤维/混凝土的抗压强度；聚丙烯-钢混杂纤维加入混凝土柱可有效提高其极限承载力。 

Calculation of bearing capacity of polypropylene-steel fiber reinforced concrete column under large eccentric loading

The cube compressive test, axial compressive test and splitting tensile test were conducted on 270 polypropylene-steel fiber/concrete test blocks with polypropylene fiber content (volume fraction) of 0vol%, 0.1vol%, 0.2vol%, 0.3vol%, 0.4vol%, 0.5vol% and steel fiber content (volume fraction) of 0vol%, 0.5vol%, 1vol%, 1.5vol% and 2vol% respectively. Based on the mechanical theory of polypropylene-steel fiber/concrete composites, the strength prediction model was established considering the fiber orientation coefficient, effective length coefficient and interfacial bond coefficient. The mechanism was also analyzed. Six polypropylene-steel fiber/concrete columns were made from polypropylene fiber with a content of 0vol%, 0.1vol%, 0.3vol% and steel fiber with a content of 0vol%, 1.5vol% to perform large eccentric compression test. On the basis of strength prediction model, the bearing capacity of polypropylene-steel fiber/concrete was calculated. The results show that steel fiber can improve the compressive strength, axial compressive strength and splitting tensile strength of polypropylene-steel fiber/concrete. Polypropylene fiber can improve the splitting tensile strength of polypropylene-steel fiber/concrete, but can’t improve the compressive strength. The ultimate bearing capacity of concrete columns can be effectively increased by adding polypropylene-steel fibers.