Study on the physicochemical properties of Chinese PVA fibers: Toward low-cost cement-based composites

Abstract

Engineered Cementitious Composites (ECC) reinforced by Japanese Polyvinyl Alcohol (PVA) fiber showed excellent tensile ductility, which attracted much attention in the field of civil engineering in recent years, but the application was still limited by cost. There were quite a few kinds of low-priced PVA fibers in China, with a tremendous difference in physical and chemical properties. In this paper, a variety of typical PVA fibers produced in different regions in China were compared with the products imported from Japan to analyze the performance differences, especially the dispersion and enhancement effect in 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 composites was summarized. The experimental results illustrated the strength and interface characteristics of PVA fibers were the dominating influencing factors to the bending and tensile properties of PVA-ECC, while hardly affected the compressive strength. Insufficient intrinsic strength of fibers significantly decreased bending resistance and tensile strength. Excessive oil agent treated PVA fibers performed lower interfacial reaction with the cement matrix, meanwhile original PVA fiber with high hydrophilicity was not conducive to the dispersion and bridging function. The appropriate interface treatment approach could guarantee the fibers 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 provided the preparation of low-cost cement-based composites, guiding the selection of fiber raw materials in ECC.