坍流时间法表征混凝土和易性的试验研究  

Research on concrete workability by slump flow time method

作　　者：孙楠 程璐璐 陈帆 李佳文 杨建森[1] SUN Nan;CHENG Lulu;CHEN Fan;LI Jiawen;YANG Jiansen(School of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学土木与水利工程学院,宁夏银川750021

出　　处：《混凝土》2020年第7期96-98,102,共4页Concrete

基　　金：宁夏大学大学生创新创业项目(X201710749411);国家自然科学基金项目(51168041)。

摘　　要：基于混凝土和易性的常用测试方法,提出了坍流时间法以表征混凝土和易性,并对其进行试验研究,建立了数学模型。结果表明:采用坍流时间表征混凝土的和易性不仅量化表征显著,而且简易可行;坍落度和扩展度与坍流时间关系满足指数函数特征且呈负显著的相关关系;掺加聚羧酸减水剂后,混凝土流动性增大,坍流时间缩短而坍落度和扩展度增大,坍流时间在0~30 s时,坍落度和扩展度下降速率较快,30 s后,下降趋于平缓;以坍流时间对混凝土和易性进行分级,不掺加减水剂和减水剂掺量小于0.4%时,混凝土坍流时间介于10~80 s之间,属于塑性混凝土和流态混凝土;掺加减水剂掺量大于0.4%时,混凝土坍流时间小于10 s,属于大流态混凝土,坍流时间法对于评定混凝土和易性具有一定优越性。Based on the commonly used test methods of concrete workability,the method of slump flow was proposed to characterize the workability of concrete,and the experimental study was carried out to establish the mathematical model.The results show that slump flow time method has significant effect on concrete workability characterization.The relationship between slump and expansion time and slump flow time satisfies exponential function and is negatively correlated.After adding polycarboxylate superplasticizer,the fluidity of concrete increases.The slump flow time is shortened and the slump and expansion degree are increased.When slump flow time is 0~30 s,the slump and expansion rate decrease rapidly,and the slump tends to be gentle after 30 s.Easy to carry out grading,without adding superplasticizer and superplasticizer dosage is less than 0.4%,the concrete slump flow time between 10~80 s,belonging to plastic concrete and fluid concrete.Admixture superplasticizer content greater than 0.4%,the slump flow time of concrete is less than 10 s,which belongs to large fluidized concrete.The slump flow time method has some advantages for assessing workability of concrete.

关 键 词：和易性 坍流时间 扩展度 坍落度 

分 类 号：TU528.01[建筑科学—建筑技术科学]