聚丙烯纤维对轻骨料混凝土物理力学性能的影响研究

Effect of Polypropylene Fiber on the Physical and Mechanical Properties of Light Aggregate Concrete

为研究聚丙烯纤维对轻骨料混凝土力学性能和工作性能的影响,通过掺加体积分数0、0.1%、0.15%、0.2%、0.25%、0.3%的聚丙烯纤维开展劈拉强度、坍落度的试验研究。探讨劈拉强度、坍落度在不同纤维掺量下的变化规律,利用细观扫描成像分析劈拉试件破坏机理和流动性的变化原因,并通过能量耗散分析纤维对混凝土各阶段的耗能能力。结果表明:随着纤维掺量的增加,坍落度持续降低;劈拉强度先增大后减小变化,且劈拉强度值均高于对照组,当纤维掺量0.25%时,劈拉强度增长率最大为27.3%;细观分析表明聚丙烯纤维起到了桥接作用,改变了试件的破坏形态,增强了混凝土韧性。能量耗散结果表明纤维提高了轻骨料混凝土的耗能能力,减弱了卸载阶段承载力的衰减程度。

In order to study the influence of polypropylene fiber on the mechanical properties and working properties of light aggregate concrete,experimental studies on the tensile strength and collapse degree of polypropylene fiber were carried out by adding polypropylene fiber with volume fractions of 0%,0.1%,0.15%,0.25%and 0.3%.The variation of splitting strength and collapse degree under different fiber dosage was discussed,the causes of the failure mechanism and fluidity of the splitting specimen were analyzed by mesoscopic scanning,and the energy consumption capacity of the fibers at various stages of concrete was analyzed by energy dissipation.The results show that with the increase of fiber dosage,the collapse degree continues to decrease.The tensile strength increased first and then decreased,and the tensile strength value was higher than that of the control group,and when the fiber dosage was 0.25%,the maximum growth rate of the cleavage strength was 27.3%;The mesoscopic analysis showed that the polypropylene fiber played a bridging role,changed the failure form of the specimen,and enhanced the toughness of the concrete.The energy dissipation results show that the fiber improves the energy consumption capacity of light aggregate concrete and weakens the attenuation degree of bearing capacity during the unloading stage.