半浸泡在Na2SO4溶液中水泥净浆不同部位化学侵蚀产物对比  

Comparison of Chemical Attack Products in Different Zones of Cement Paste Partially Immersed in Na2SO4 Solution

作　　者：刘赞群[1,2] 裴敏 张丰燕 邓德华[1,2] LIU Zanqun;PEI Min;ZHANG Fengyan;DENG Dehua(School of Civil Engineering, Central South University, Changsha 410075, China;National Engineering Laboratory for High-Speed Railway Construction Technology, Central South University, Changsha 410075, China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学高速铁路建造技术国家工程实验室,湖南长沙410075

出　　处：《建筑材料学报》2020年第3期485-492,共8页Journal of Building Materials

基　　金：国家自然科学基金资助项目(51378058)。

摘　　要：在(20±1)℃、相对湿度(80±5)%和氮气环境下,将水灰比为0.35、0.45和0.55的硅酸盐水泥净浆试件半浸泡在质量分数5%的Na2SO4溶液中,侵蚀50、100d后,采用X射线衍射和热重分析,研究了试件蒸发区和浸泡区中化学侵蚀产物的含量.结果表明:试件蒸发区中钙矾石和石膏含量显著多于浸泡区中的含量,而且随着浸泡时间的延长,蒸发区和浸泡区的产物含量的差值增大;侵蚀100d后,水灰比为0.55的水泥净浆试件中蒸发区和浸泡区的产物含量的差值与其他2种水灰比的试件相比,有2倍的增长;硫酸盐化学侵蚀破坏是导致半浸泡在硫酸盐环境中的水泥净浆蒸发区破坏的主要原因.Portland cement paste specimens made with different water-cement ratios of 0.35,0.45 and 0.55 were partially immersed in 5%Na2SO4 solution under a constant nitrogen atmosphere and at temperature of(20±1)℃and(80±5)%relative humidity.After 50,100d partial immersion,the chemical attack products in the evaporation zone and immersed zone of specimens were quantitatively analyzed by means of X ray diffraction and thermogravimetry.Test results show that the content of chemical attack products of ettringite and gypsum formed in the evaporation zone is much more than that in the immersed zone,and the content difference of products between the two zones grows with the increase of partial immersion time.After 100d partial immersion,the content difference of products between the two zones in the paste with water-cement ratio of 0.55 is double than that of the other two pastes.The test results quantitatively confirm that the damage of evaporation zone of concrete partially immersed in sulfate environment is mainly caused by the chemical sulfate attack.

关 键 词：硅酸盐水泥 硫酸盐 化学侵蚀 物理盐结晶 碳化 

分 类 号：TQ172.1[化学工程—水泥工业]