聚乙烯醇纤维增强水泥基复合材料轴压徐变性能研究

Study on the Creep Behavior of Polyvinyl Alcohol Fiber Reinforced Engineered Cementitious Composite

通过自制加载装置,研究了聚乙烯醇纤维(PVA)增强水泥基复合材料在轴向压应力作用下的徐变性能。研究参数包括水胶比和纤维掺量。研究结果表明:纤维掺入会降低水泥基复合材料抵抗徐变的能力,相对于未掺纤维的水泥基复合材料,纤维掺量为1%时其120 d徐变增加了19.4%;适当的水胶比有利于胶凝材料充分反应,增加对PVA水泥基复合材料对徐变的抑制作用,当水胶比超过0.3时PVA水泥基复合材料的力学性能会出现一定程度的降低,且120 d徐变会呈现快速增加。基于分数阶导数理论,采用Abel粘壶替代标准线性固体模型中的牛顿粘壶,推导出用于描述水泥基复合材料的徐变模型,并利用该徐变模型对试验数据进行分析。结果表明,含Abel粘壶的徐变模型与试验数据吻合良好且稳定性较高。

A loading equipment was proposed to study on the creep behavior of polyvinyl alcohol fiber reinforced engineered cementitious composite under axial compressive stress.Experimental variables include water to binder ratio and fiber fraction.The results show that the PVA fiber added to engineered cementitious composite(ECC)reduced the creep resistance of engineered cementitious composite.When the fiber fraction was 1%,the 120 d creep of engineered cementitious composite increased by 19.4%compared with those without fiber addition.Appropriate water to blinder ratio is in favor of the sufficient reaction and increasing the creep resistance of PVA-ECC composites.When the ratio of water to binder is over 0.3,the mechanical properties of PVA-ECC composites will decrease,meanwhile 120 d creep will increase rapidly.Based on the theory of fractional order derivative,the creep model is deduced by using the Abel dashpot instead of the Newton dashpot in a standard linear model,and experimental date are analyzed by the creep model.The results show that the creep model is in good agreement with the experimental data and high stability.