摘要
用变形测试、热重分析和化学滴定方法,系统研究了葡萄糖酸钠和柠檬酸钠2种缓凝剂对掺有CaO膨胀剂水泥净浆不同龄期自由自生体积变形、限制自生体积变形,以及CaO膨胀熟料水化速率、水化进程等方面的影响。结果表明:缓凝剂的使用延缓了CaO膨胀剂水化进程,0.08%掺量下纯水中11h和水泥净浆中7d水化程度分别降低了15%和25%以上;增大了水泥净浆自由自生体积变形,0.08%掺量下28d较基准提高了50%以上;减小了约束状态下的限制自生体积变形,0.08%掺量下最大膨胀率降低了超过90%以上,从而抑制了CaO膨胀剂的膨胀指数和膨胀效能。绝大多数实际情况下有约束存在时,不利于对水泥基材料收缩的补偿。
By using the deformation test, differential scanning calorimetry and chemical titration technique, the influences of retarders on the free autogenous volume deformation and limited autogenous volume deformation of cement paste doped with CaO expansion agent at different ages were systematically investigated, as well as the hydration rate and hydration process of CaO expansion clinker. Two types of retarders were used as following： sodium gluconate and sodium citrate. The experimental results show that with the addition of 0. 08%, the two retarders can delay the hydration process of CaO agent by more than 15% in deionized water at 11 h and more than 25% in cement paste at 7 d. They increase the free autogenous volume deformation of cement paste by more than 50% at 28 d and decrease the maximum limited autogenous expansion rate by more than 90% in the constrain condition. Therefore, the retarders lower the expansion index and efficiency of CaO expansion agent. In the over- whelming majority of practical cases, restraints exist and the use of retarders goes against the shrinkage compensating of cement- based materials.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2014年第2期184-189,共6页
Journal of The Chinese Ceramic Society
基金
国家杰出青年基金(51225801)资助项目
关键词
膨胀剂
缓凝剂
自生体积变形
膨胀指数
水化进程
expansion agent
retarder
autogenous volume deformation
expansion index
hydration process
