低水胶比高性能纤维增强水泥基复合材料性能研究

Study on properties of high performance fiber-reinforced cement composites with low water-binder ratio

在水胶比为0.19~0.28范围内,制备了高性能纤维增强水泥基复合材料,研究了水胶比对水泥基复合材料工作性能、力学性能、干缩性能及微观形貌的影响。结果表明:在水胶比为0.19~0.28范围内,随着水胶比的减小,新拌浆体的黏聚性逐渐增大,流动性逐渐降低,含气量增大;水胶比<0.22会对纤维与水泥基材的粘结造成不利影响,降低其极限延伸率和折压比;水胶比对水泥基复合材料干缩影响显著,干缩90%以上发生在10 d养护龄期以内,10 d后收缩率几乎不再增长;水胶比≤0.22条件下,试件破坏时纤维被拔断,水胶比≥0.25条件下,试件破坏时纤维被拔出,纤维拔出比拔断更有利于极限延伸率的提高。

High performance fiber-reinforced cement composites were prepared in the range of 0.19~0.28 W/B,and the effects of water binder ratio on the working properties,mechanical properties,dry shrinkage and micro morphology of cement-based composites were studied.The results showed that:in the range of 0.19~0.28 W/B,with the decrease of W/B,the viscosity of newly mixed slurry increased gradually,the fluidity decreased gradually,and the gas content increased.The W/B less than 0.22 will have a negative impact on the bond between the fiber and the cement substrate,and reduce its limit elongation and folding ratio.The W/B has a significant effect on the dry shrinkage of high performance fiber-reinforced cement composites.The dry shrinkage of more than 90%occurs within the curing age of 10 d,and the shrinkage rate hardly increases after 10 d.The fiber was pulled off when W/B is less than 0.22.The fiber was pulled out when W/B is higher than 0.25.The Pull out is more beneficial to increase the ultimate elongation than the pull off.