聚丙烯粗纤维对泵送混凝土性能的影响及灰色关联分析

为研究聚丙烯粗纤维掺量、长径比对泵送混凝土和易性与力学性能的影响,在基准混凝土中加入不同掺量和长径比的聚丙烯粗纤维,开展聚丙烯粗纤维混凝土(CPFRC)坍落度、扩展度、抗压强度和劈裂抗拉强度试验,并基于灰色关联理论量化纤维掺量、长径比的增强效应。研究结果表明,聚丙烯粗纤维对泵送混凝土的坍落度、扩展度、抗压强度和劈裂抗拉强度影响显著。相比于基准混凝土,聚丙烯粗纤维掺量为3 kg/m³时,混凝土和易性表现最优,抗压强度的增强效应最好,坍落度与扩展度分别降低了1.41%和15.76%,7 d、14 d和28 d抗压强度分别增长了20.42%、14.96%和11.49%;聚丙烯粗纤维掺量为6 kg/m³时,混凝土劈裂抗拉强度的增强效果最为明显,7 d、14 d和28 d劈裂抗拉强度分别增长了27.46%、13.61%和15.92%。当聚丙烯粗纤维掺量为3 kg/m³,长径比为47.5时,混凝土的和易性与力学性能最优,长径比对和易性与力学性能的总关联度达到0.849。

Influence of Coarse Polypropylene Fiber on Performance of Pumping Concrete and Grey Correlation Analysis

To study the influences of coarse polypropylene fiber content and length-diameter ratio on the workability and mechanical properties of pumped concrete,the tests of slump,expansion,compressive strength and splitting tensile strength of coarse polypropylene fiber reinforced concrete(CPFRC)were carried out with base concrete adding coarse polypropylene fiber with different dosages and length-diameter ratios.In addition,the enhancement effects of the fiber content and length-diameter ratio were quantified on the basis of the gray correlation theory.The research results show that the content of coarse polypropylene fiber and the length-diameter ratio have significant effects on slump,expansion,early compressive strength and splitting tensile strength of pumped concrete.Compared with the base concrete,when the coarse polypropylene fiber content is 3 kg/m³,CPFRC has the best workability and the compressive strength enhancement effect.And the slump and the expansion degree reduce by 1.41%and 15.76%,while the compressive strength of 7 d,14 d and 28 d increase by 20.42%,14.96%and 11.49%,respectively.When the content of coarse polypropylene fiber is 6 kg/m³,the splitting tensile strength enhancement effect of concrete is the most obvious,and the splitting tensile strength of 7 d,14 d and 28 d increase by 27.46%,13.61%and 15.92%,respectively.The workability and mechanical properties of CPFRC are optimized when the content of coarse polypropylene fiber is 3 kg/m³and length-diameter ratio reaches 47.5,and the total correlation of the workability and the mechanical properties reaches 0.849.