冻融循环对粉煤灰混凝土氯离子扩散系数的影响  

Effects of Freeze-thaw Cycles on Chloride Diffusion Coefficient of Fly Ash Concrete

作　　者：李强[1,2] 余红发[1] 张立明[1] 

机构地区：[1]南京航空航天大学土木工程系,江苏南京210016 [2]浙江建设职业技术学院,浙江杭州311231

出　　处：《应用基础与工程科学学报》2015年第3期622-628,共7页Journal of Basic Science and Engineering

基　　金：国家重点基础研究发展计划(973计划)项目(2009CB623203);浙江省自然科学基金项目(LY12E08003);浙江省科技计划项目(2013C31011);住房和城乡建设部科技项目(2012-K2-13)

摘　　要：测定不同冻融循环次数的混凝土氯离子含量,应用二维扩散理论模型计算混凝土氯离子扩散系数.结果表明:混凝土中的自由Cl-浓度(Cf)随着扩散深度的增加而降低,随着冻融循环次数的增加而升高;混凝土的氯离子扩散系数Dt随着冻融循环次数的增加而逐渐降低,随着粉煤灰含量的增加而先增加后降低;混凝土的Dt与冻融循环次数和粉煤灰掺量分别呈幂函数关系和呈二次函数关系.利用冻融循次数室内外换算关系,建立服役时间和粉煤灰掺量与Dt方程,可用来估算现场环境下不同服役周期实际工程混凝土的氯离子扩散系数.The chloride ion content of concrete in different freeze-thaw cycles was measured,and chloride ion diffusion coefficient was calculated by two dimensional diffusion models. The test results show that free chloride ion concentration decreased with the increase of diffusion depth and increased with the increase of freeze-thaw cycles respectively. However,the chloride diffusion coefficient of concrete decreased with the increase of freeze-thaw cycles,and increased firstly and then decreased with the increase of fly ash content in concrete. It was found that the chloride diffusion coefficient of concrete changed in power law with freeze-thaw cycles and in quadratic function with fly ash content. The equation of chloride ion coefficient with service life and fly ash content was derived by using the conversion between indoor and outdoor freeze-thaw cycles. It can be used to predict the chloride ion diffusion coefficient of engineering concrete in different service environment.

关 键 词：混凝土 冻融循环 氯离子(Cl-) 扩散系数 

分 类 号：TU528.0[建筑科学—建筑技术科学]