PVA纤维增强水泥基复合材料拉伸性能的影响因素研究

Study on the Influencing Factors of Tensile Properties of PVA Fiber Reinforced Cementitious Composites

通过聚乙烯醇纤维增强水泥基复合材料(PVA-ECC)轴向拉伸试验,研究了水胶比、PVA纤维掺量、砂的种类和级配对PVA-ECC拉伸性能的影响,并利用扫描电镜(SEM)分析了砂种类和级配的影响机理。结果表明:当水胶比在0.28~0.34范围内时,PVA-ECC的极限拉应变随水胶比的增大而降低,当水胶比由0.28增至0.32时,PVA-ECC的极限拉应变仍大于3.0%,而当水胶比达到0.34时,PVA-ECC的极限拉应变小于3.0%;随着PVA纤维掺量的增加,PVA-ECC的极限抗拉强度增大,但极限拉应变呈先减小后增大的趋势;砂的种类和级配对PVA-ECC的拉伸性能有影响,选择粒径为0.075~0.150 mm的石英砂作为PVA-ECC的细骨料对PVA-ECC的拉伸性能最有利。

Through the axial tensile test of polyvinyl alcohol fiber reinforced cementitious composite(PVA-ECC),the effects of water-binder ratio,PVA fiber content,sand type and gradation on the tensile properties of PVA-ECC were studied.The influence mechanism of sand type and gradation was analyzed by scanning electron microscope(SEM).The results show that when the water-binder ratio is in the range of 0.28~0.34,the ultimate tensile strain of PVA-ECC decreases with the increase of water-binder ratio.When the water-binder ratio increases from 0.28 to 0.32,the ultimate tensile strain of PVA-ECC is still greater than 3.0%,but when the water-binder ratio reaches 0.34,the ultimate tensile strain of PVA-ECC is less than 3.0%.With the increase of PVA fiber content,the ultimate tensile strength of PVA-ECC increases,but the ultimate tensile strain decreases first and then increases.The sand type and gradation have an impact on the tensile properties of PVA-ECC.Selecting quartz sand with a particle size of 0.075~0.150 mm as the fine aggregate of PVA-ECC is the most favorable for the tensile properties of PVA-ECC.