摘要
为研究碱含量对水泥水化初期水化硬化特性的影响,利用光学法微流变测量不同碱含量水泥在硬化过程中的黏弹性变化规律,同时测定不同碱含量水泥浆体流动度的经时变化与凝结时间.结果表明:光学法微流变能准确表征水泥浆体硬化过程中的黏弹性能变化.水泥浆体的黏弹性在拌水20min内急剧增大,之后增长速率减小,维持在基本稳定的状态.碱含量对水泥浆体黏弹性能的影响与水泥凝结时间及流动度变化规律相一致.低碱条件下(<0.83%Na_(2)O_(eq)),随着碱含量的增加,水泥浆体的弹性因子与宏观黏度因子减小,水泥凝结延缓,浆体初始流动度增大;随着碱含量的继续增加,浆体弹性因子与宏观黏度因子由减小转为增大,水泥凝结提前,浆体初始流动度减小.相比于普通水泥,碱含量对低C_(3)A含量水泥的黏弹性能、凝结时间及流动度的影响程度更大.
To investigate the influence of alkali content on hydration and hardening properties of cement in early age,the viscoelasticity variation of cement paste with different alkali content during hardening process was studied by optical micro-rheological method,meanwhile,the time-dependent fluidity loss and setting time of cement paste with different alkali content were measured.The results show that the optical micro-rheometer can characterize viscoelasticity variation of cement paste during hardening process precisely.The viscoelasticity of cement paste increase sharply in the first 20 min after mixing,then their growth rates decrease and keep at a stable level.The influence of alkali content on the viscoelasticity of cement is consistent with that of the setting and the fluidity.The increase in alkali content in cement lead to decrease in elastic index and macroscopic viscosity index of fresh cement paste,delayed setting time and decrease in fluidity of fresh cement paste when the alkali content in cement is low(less than 0.83%Na_(2)O_(eq)),with the consecutive increase of alkali content,the elastic index and macroscopic viscosity index turn from decreasing to increasing,the setting time is shortened and the fluidity is decreased.Compared with general cement,the alkali content has a greater influence on the viscoelasticity,setting and fluidity of cement with low C_(3)A content.
作者
黄磊
阎培渝
高玉亭
张慧杰
HUANG Lei;YAN Peiyu;GAO Yuting;ZHANG Huijie(Department of Civil Engineering,Qinghai University,Xining 810016,China;Department of Civil Engineering,Tsinghua University,Beijing 100084,China;Shenzhen Construction Engineering Group Corporation,Shenzhen 518051 China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2021年第6期1450-1460,共11页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(51878381)
关键词
水泥
微流变
碱含量
黏弹性
凝结
流动度
cement
microrheology
alkali content
viscoelasticity
setting
fluidity
作者简介
黄磊(1986—),男,讲师,博士.E-mail:leihyx@foxmail.com;通讯作者:阎培渝(1955—),男,教授,博士生导师.E-mail:yanpy@tsinghua.edu.cn
