摘要
目的研究相对湿度对混凝土和砂浆收缩率和收缩规律的影响,并通过砂浆孔结构分析,阐明孔结构和相对湿度对收缩率及收缩规律的影响机理.方法混凝土收缩按照GBJ82-1985的方法进行;砂浆收缩参照JC476-2001进行;砂浆孔结构采用BET法测试.结果相对湿度为58%时,掺减水剂砂浆或混凝土的收缩率显著大于不掺减水剂,而当相对湿度大于80%时,收缩率则小于不掺减水剂.孔半径在2.0 nm^4.9 nm之间的孔体积,掺减水剂砂浆显著大于不掺减水剂的基准砂浆.结论相对湿度对砂浆和混凝土的收缩率及收缩规律影响十分显著,不同相对湿度条件可能导致完全相反的收缩率比试验结果.掺减水剂增大收缩的主要原因之一是微孔体积显著增大.当掺减水剂砂浆或混凝土长期在相对湿度大于80%的环境中使用时,并不增加干燥收缩率.
Influence of relative humidity on the shrinkage ratio and regularity of mortar and concrete was studied. Effects and mechanics of pore structure and relative humidity on the shrinkage ratio and regularity were also clarified by analyzing the pore structure of mortar. Testing methods for shrinkage of concrete and mortar and pore structure of mortar function according to GBJ82 - 1985, JCA76 - 2001 and BET method works separately. The shrinkage ratio of mortar and concrete to superplasticizer increases significantly when the relative humidity is 58 %. However, it is less than the concrete without superplasticizer when the relative humidity is above 80%. Compared with reference mortar without superplasticizer, the volume of pore between 2.0- 4.9 nm significantly increases when superplasticizer is added. Relative humidity has an effect on the shrinkage ratio and regularity of mortar and concrete. Testing results of shrinkage ratio may be in contrast when relative humidity has changed. One of the main reasons why superplasticizer increases the shrinkage is that it increases the volume of micropore. The drying shrinkageratio of mortar and concrete to Superplasticizer doesn＇t increase when the relative humidity is above 80%.
出处
《沈阳建筑大学学报（自然科学版）》
EI
CAS
2006年第2期268-271,共4页
Journal of Shenyang Jianzhu University：Natural Science
基金
国家中小企业创新基金(02C26213300599)
浙江省科技厅重点科技项目(2003C21018)
关键词
砂浆
混凝土
减水剂
干燥收缩
相对湿度
孔结构
mortar
concrete
superplasticizer
drying shrinkage
relative humidity
pore structure
