国产PVA纤维理化特性及其水泥基复合材料性能研究

Study on physical and chemical properties of domestic PVA fiber and properties of PVA-ECC

日本生产的高强高弹模聚乙醇纤维(PolyvinylAlcohol,PVA)增强水泥基复合材料(ECC)具有优异的拉伸延性,近年来在土木工程领域备受关注,然而受高昂的成本限制无法规模化应用。国产PVA纤维种类繁多,制得水泥基复合材料性能参差不齐。选用多种国内不同地区生产的典型PVA纤维对比日本进口产品,分析国内外纤维增强水泥基复合材料的性能差异,结合各纤维理化特性,从多个维度总结归纳纤维原材料的特征与复合材料性能间的关系,试验结果表明纤维本体强度和界面特性都是影响PVA-ECC材料抗折和拉伸性能的关键,但是对抗压性能影响不大,纤维本征强度不足会显著降低抗折和拉伸强度,纤维表面油剂过多会降低和水泥基体的化学结合能不利于应变硬化,纤维表面亲水性过高则不利于纤维的分散和桥联作用的发挥,合适的界面处理方式可保障纤维实现滑移拔出桥联作用同时也满足较高的滑移强化作用,赋予ECC材料多缝开裂和应变硬化特性。本研究对纤维增强水泥基复合材料中纤维原料的选用提供参考,为制备低成本国产化PVA-ECC材料提供必要的试验数据支撑。

Japanese high strength and high elastic mold Polyvinyl Alcohol(PVA)fiber reinforced cement based composite material also known as Engineered Cementitious Composites(ECC)has excellent tensile ductility,which has attracted much attention in the field of civil engineering in recent years,but it cannot be applied in large scale due to the high cost limit.There are many kinds of domestic PVA fibers,made huge difference in the the performance of cement matrix composite materials.In this paper,a variety of typical PVA fibers produced in different regions in China are compared with the products imported from Japan to analyze the performance differences of domestic and foreign fiber reinforced cement matrix composites.Combining with the physical and chemical characteristics of each fiber,the relationship between the characteristics of fibers and the properties of composite materials is summarized.The experimental results show that the strength and interface characteristics of PVA fibers are the key influencing factors to the folding and tensile properties of PVA-ECC materials,while hardly affect the compressive strength.Insufficient intrinsic strength of fibers significantly reduces folding resistance and tensile strength.Excessive oil agent treated PVA fiber perform lower chemical binding energy with the cement matrix,while high hydrophilicity of the fiber is not conducive to the dispersion and bridging function.Only the appropriate interface treatment method can guarantee the fiber to achieve the sliding pull out bridge connection,and also meet the high slip strengthening effect,leading to the multi-seam cracking and strain hardening characteristics of ECC material.This work provides a reference for the selection of fiber raw materials in fiber-reinforced cement matrix composite materials,and provides the necessary experimental data support for the preparation of low-cost domestic PVA-ECC materials.