Effects of Curing Condition on the Carbonation of Shrinkage-compensated Concrete  

作　　者：MA J T TU L Q SHUI Z H CHEN W 

机构地区：[1]School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China [2]Wuhan Harbour Engineering Design & Research Co. Ltd,Wuhan 430071,China

出　　处：《武汉理工大学学报》2010年第17期103-107,共5页Journal of Wuhan University of Technology

基　　金：supported by the National Fundamental Scientific Research Project(PR China),relevant to"Basic research in Environmentally Friendly Concrete (2009CB623201)"

摘　　要：Shrinkage-compensating concrete can enhance the permeability and strength. In addition,expansive admixture can densify concrete to advance the carbonation resistance ability. Due to special quality of ettringite,the relative humidity of curing environment has significant effect on the carbonation rate of concrete. This paper discusses the influence of environmental humidity on carbonation rate of shrinkage-compensating concrete. Four different curing conditions were set up,namely the natural environment (RH 60%),standard environment (RH 90%),early age water curing environment for 3 d and 7 d. After curing in these four environments for 28 d,an accelerated carbonation test was performed. Micro-hardness analysis was used to evaluate surface hardness,which depends on,to a great degree,the carbonation depth. TG-DSC analysis was used to study Ca(OH)2 content gradient in the surface layer of concrete in different environment. The results show that natural condition lead to a relatively worse carbonation degree,curing in water for 3 d is harmful to the carbonation resistance,while curing in water for 7 d lead to an equivalent carbonation degree with standard condition,which show the most improvement to carbonation resistance ability.Shrinkage-compensating concrete can enhance the permeability and strength. In addition,expansive admixture can densify concrete to advance the carbonation resistance ability. Due to special quality of ettringite,the relative humidity of curing environment has significant effect on the carbonation rate of concrete. This paper discusses the influence of environmental humidity on carbonation rate of shrinkage-compensating concrete. Four different curing conditions were set up,namely the natural environment （RH 60%）,standard environment （RH 90%）,early age water curing environment for 3 d and 7 d. After curing in these four environments for 28 d,an accelerated carbonation test was performed. Micro-hardness analysis was used to evaluate surface hardness,which depends on,to a great degree,the carbonation depth. TG-DSC analysis was used to study Ca（OH）2 content gradient in the surface layer of concrete in different environment. The results show that natural condition lead to a relatively worse carbonation degree,curing in water for 3 d is harmful to the carbonation resistance,while curing in water for 7 d lead to an equivalent carbonation degree with standard condition,which show the most improvement to carbonation resistance ability.

关 键 词：shrinkage-compensating concretes curing humility ettringite reaction carbonation rate 

分 类 号：TU528.064[建筑科学—建筑技术科学]