聚丙烯纤维提高水泥砂浆抗塑性开裂的机理  

Mechanism research on improvement of resistance to plastic shrinkage and cracking of cement mortar by polypropylene fibers

作　　者：钱春香[1] 耿飞[1] 李丽[1] 

机构地区：[1]东南大学绿色建材技术研究所,南京210096

出　　处：《东南大学学报（自然科学版）》2005年第5期786-791,共6页Journal of Southeast University：Natural Science Edition

基　　金：国家重点基础研究发展计划(973计划)资助项目(2001CB610705)

摘　　要：研究了聚丙烯纤维掺量、长度和截面形状对砂浆早期塑性收缩抗裂性能、塑性抗拉强度和表面水分蒸发率的影响,结果表明:随着纤维掺量和长度的增加,抗塑性收缩开裂的效果随之提高;纤维长度对塑性收缩抗裂的影响较其掺量要复杂得多;截面形状为多边形的聚丙烯纤维对提高砂浆塑性收缩抗裂效果要好于圆形的.纤维掺量、长度及比表面积的增加有利于提高砂浆(水灰质量比0.36,灰砂质量比1∶2)的塑性抗拉强度,而对砂浆水分蒸发率的影响不是非常显著.聚丙烯纤维对塑性收缩抗裂的效果主要取决于其对塑性抗拉强度的提高.结合理论和试验分析,归纳出了聚丙烯纤维提高砂浆抗塑性开裂性能的效应图.The effect of weight fraction, length and cross section shape of polypropylene fibers on cracking resistance, tensile strength and surface moisture evaporating speed of mortar at early-age plastic shrinkage was inv.estigated. The experimental results show that the total cracking area reduces with the increase of weight fraction and length of polypropylene fibers and the fibers with polygonal cross section perform better than those with circular cross section in improving the cracking resistance of mortar. On all accounts, it shows that with the increase of weight fraction, length and specific surface area of polypropylene fibers, the tensile strength of mortar （ water cement ratio, 0.36 ; sand cement ratio, 1：2） increases significantly, but the surface moisture evaporating speed of mortar does not change much. The improvement of cracking resistance of mortar at plastic shrinkage is attributed to the increase of tensile strength of mortar dut to the addition of polypropylnene fibers. Based on the experiment and theoretical analysis, a graph of the effect of polypropylene fibers on early-age plastic shrinkage and cracking of mortar is constructed.

关 键 词：聚丙烯纤维 塑性收缩和开裂 塑性抗拉强度 水分蒸发 

分 类 号：TU377.9[建筑科学—结构工程]