【摘要】 为探索聚丙烯纤维(polypropylene fiber,PPF)长度和掺量对低坍落度混凝土的影响,设计了171组基准混凝土和PPF混凝土标准立方体试块,尺寸为150 mm×150 mm×150 mm,并开展了常温下和高温后低坍落度混凝土的抗压强度试验和劈裂抗拉强度试验。基于试验结果给出PPF对低坍落度混凝土抗压强度和劈裂抗拉强度的影响规律,并结合电镜扫描结果分析低坍落度PPF混凝土的微观结构和破坏机理。结果表明:在适宜的长度和掺量范围下,PPF的掺入较明显改善高温前后的力学性能;同时在一定掺量下,发现PPF高温气化有助于混凝土的应力释放,提高了残余抗压强度。更多还原

【Abstract】 To investigate the effects of PPF(polypropylene fiber) addition in different lengths and contents into low-slump concrete, 171 sets of cube specimens(150 mm×150 mm×150 mm) were designed, and their compressive strength and splitting tensile strength were tested under normal and high temperatures. Based on large numbers of experiments, the mechanism of PPF-modified low-slump concrete on compressive strength and splitting tensile strength was discussed. Meantime, the microstructure of the modified concrete was studied with SEM to reveal the failure mechanism of the concrete. The results show that the mechanical properties of PPF-modified concrete before and after high temperature treatment were largely improved by heat treatment under appropriate length and content ranges. In addition, gasification of PPF after thermal treatment in a certain admixture is helpful for the stress release of the concrete, which improved the residual compressive strength.更多还原