天然纤维增强水泥基材料轴拉性能试验研究

Experimental Study on Uniaxial Tension of Natural Fiber Reinforced Cement-based Materials

工程水泥基复合材料(简称ECC)能改善普通混凝土脆性、耐久性差的问题,但聚乙烯醇(PVA)纤维的较高价格,一定程度上局限了ECC的推广应用。本文主要从天然纤维入手,研究体积掺量为2%竹原、苎麻、剑麻、大麻这四种纤维组成的水泥基材料的轴拉性能,将四种纤维分别以干铺和湿铺两种方式,采用哑铃型试件做单轴拉伸试验。试验结果表明,四种纤维在所选取的配比范围内,在拉伸荷载作用下应力-应变关系可分为弹性上升阶段、应变硬化阶段和应变软化阶段,且均能实现应变硬化与多缝开裂,极限拉应变最大可达3.5%。

ECC（Engineering Cementitious Composites） can improve brittleness and poor durability of ordinary concrete, but the higher price of PVA fiber limits the generalization and application of ECC to some degree. Here, based on the natural fibers, axial tensile properties of ECC with 2% volume content of bamboo, ramie, sisal or hemp are studied, the four kinds of fiber are treated using two ways of wet-laid and dry-laid, and the dumbbell specimens are made to carry out the uniaxial tension test. The results show that when the four kinds of fiber is within range of the selected ratio, under the tensile loads stress-strain relationship has elastic rise stage, strain hardening stage and strain softening stage, and strain hardening and multiple joints cracking are achieved, the ultimate tensile strain is up to 3.5%.