混杂聚乙烯醇纤维增强水泥基复合材料力学性能

Study on Mechanical Properties of Hybrid PVA Fibers Reinforced Cementitious Composites

目前配置ECC(engineered cementitious composites,ECC)的聚乙烯醇纤维(polyvinyl alcohol,PVA)主要由日本可乐丽公司生产,成本较高.国产PVA价格合理,但国产PVA-ECC的拉伸延性有限,为了进一步提高水泥基复合材料的拉伸延性,兼顾应用成本,将国产PVA纤维和日本产PVA纤维以一定的比例混合,配制混杂PVA-ECC,为实际工程结构性能提升提供更多的材料选择.首先基于微观力学模型,确定混杂PVA-ECC中PVA纤维的体积分数,对设计的5组不同配合比的混杂PVA-ECC试件进行四点弯试验、单轴拉伸试验及单轴压缩试验,确定混杂PVA-ECC的较优配合比.最后对典型配合比ECC进行性能和成本对比分析,提出了低成本、较低拉伸性能的配合比M7,中等成本、较高拉伸性能的配合比M17和高成本、高拉伸性能的配合比M21等3个具有代表性的配合比,供实际工程根据结构性能的需要进行选择.采用混杂PVA纤维配置ECC,可降低ECC的成本,使得ECC大量应用于工程实践成为可能.

At present,the PVA （polyvinyl plcohol） fiber used in ECC （engineered cementitious composites） mainly produced by KURARAY Co.Ltd.,Japan,and its cost is very high.The price of domestic PVA fiber is reasonable,however,the tensile ductility of the domestic PVA-ECC is limited.To further increase the tensile ductility of ECC,looking after both side the cost,domestic PVA fiber was mixed with Japanese one at a proper proportion to develop hybrid PVA-ECC.Based upon the micromechanics model,the mix proportion was redesigned through the parametric analysis.The four-point bending test,uniaxial tensile test and uniaxial compressive test were carried out to characterize the mechanical behavior of hybrid PVA-ECC with five mix proportions.According to the performance and cost of the material,three typical mixes were proposed：M7 with low cost,relatively low tensile ductility and reinforced by domestic PVA fiber,M17 with moderate cost,relatively high tensile ductility and reinforced by hybrid PVA fiber and M21 with high cost,high tensile ductility and reinforced by Japanese PVA fiber.In practical applications which mix to be chosen depends on the structural performance to be achieved.The development of hybrid ECC helps cut costs of ECC,and the widespread use of ECC becomes possible.