纤维素纤维对砂浆干缩性能的影响  

Effects of Cellulose Fiber on Drying Shrinkage Performance of Cement Mortar

作　　者：邓宗才[1] 张永方[1] 杜超超[1] 

机构地区：[1]北京工业大学城市与重大工程安全减灾省部共建重点实验室,北京100124

出　　处：《南水北调与水利科技》2012年第5期88-92,共5页South-to-North Water Transfers and Water Science & Technology

摘　　要：水泥基材料极易干缩开裂,因此一般在水泥基体中掺入纤维来限制其干缩。为研究纤维素纤维对水泥基材料干缩性能的影响,现通过对比不同水胶比及纤维素纤维掺量下水泥砂浆的干缩性能,分析了纤维掺量对水泥砂浆干缩性能的影响规律,探讨了纤维素纤维改善水泥砂浆抗干缩性能的机理,并与聚丙烯纤维进行对比分析,确定干缩变形较小的纤维种类与合理掺量。试验结果表明:纤维砂浆的干缩值随水灰比的增大而增大,纤维砂浆的干缩随龄期的变化呈指数关系;纤维素纤维的掺入显著降低了水泥砂浆早期干缩的变化速率,大大减少了砂浆的硬化后期干缩值,并且砂浆干缩值随着纤维素纤维掺量的增加而降低;纤维素纤维的经济掺量为1.1kg/m3。Cracks are often found in cement based materials,and adding the fiber into the materials can limit the drying shrinkage.In order to investigate the effects of cellulose fiber on the drying shrinkage performance of cement based materials,the drying shrinkage characteristics of the cement mortar with different water-binder ratios and different contents of cellulose fiber were analyzed to identify the improvement mechanism of the cellulose fiber on the drying shrinkage of cement mortar.In addition,the cellulose fiber was compared to the polypropylene fiber,which can help determine the type of fiber with smaller drying shrinkage and the reasonable fiber content.The results indicated that with the increasing of water-binder ratio,the drying shrinkage value of the fiber mortar increased,and the drying shrinkage of fiber mortar was in an exponential relationship with the age.Adding the cellulose fiber can decrease the rate of early drying shrinkage significantly,and also decrease the drying shrinkage value greatly during the hardened period.Moreover,the drying shrinkage value of mortar decreased with the increasing of the content of the cellulose fiber.The economical content of cellulose fiber was 1.1 kg/m3.

关 键 词：砂浆 干缩 水泥基材 纤维素纤维 水胶比 纤维掺量 

分 类 号：TU528.572[建筑科学—建筑技术科学]