聚乙烯醇纤维及钢纤维增强水泥砂浆流变性和流动性能

为探索纤维对水泥砂浆拌和物工作性能的影响,采用流变仪、微型坍落度筒和V型漏斗研究了不同水灰比和纤维掺量(体积分数)下,聚乙烯醇(PVA)纤维及钢纤维增强水泥砂浆拌和物的流变性和流动性能.结果表明:2种纤维增强水泥砂浆拌和物的屈服应力和塑性黏度均随着水灰比的增大而减小,而流动扩展度和流动速率均随着水灰比的增大而增大;PVA纤维掺量为0.25%时,对拌和物工作性能的影响较小;钢纤维掺量小于0.75%时,能够促进纤维增强水泥砂浆拌和物流动;钢纤维掺量继续增加至1.00%时,拌和物的流动性则明显降低.纤维增强水泥砂浆拌和物的流动扩展度与屈服应力、流动速率与塑性黏度均呈负指数关系,相关系数分别为0.808和0.730.

Rheology and Flowability of Polyvinyl Alcohol Fiber and Steel Fiber Reinforced Cement Mortar

Rheology and flowability of polyvinyl alcohol fiber and steel fiber reinforced cement mortar were investigated by rheometer, mini slump cone and V funnel. The effects of different fibers on the workability of fresh cement mortar were then studied. The results indicate that the yield stress and plastic viscosity of fresh fiber reinforced cement mortars decrease with increasing water cement ratio, while the flow spread and flow rate increase. The influence of PVA fiber on the flowability of mortar is slight at PVA fiber content of 0.25%(by volume), while steel fiber plays a role in promoting the flowability of cement mortar at steel fiber content below 0.75%(by volume). With steel fiber content increasing to 1.00%(by volume), the hindering effect of steel fiber on the flowability becomes remarkable. There are negative exponent correlations between flow spread and yield stress, flow rate and plastic viscosity, and the correlation coefficients are 0.808 and 0.730, respectively.