氯盐环境下混凝土冻融循环及孔结构演化研究  

Research on concrete damage and pore structure evolution under freeze-thaw cycles in chloride solution

作　　者：蒋科 郭辉[1] 李洋[1] 殷海波[1] 肖开涛[1] JIANG Ke;GUO Hui;LI Yang;YIN Haibo;XIAO Kaitao(Engineering Quality Inspection Center,Changjiang River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]长江科学院工程质量检测中心,湖北武汉430010

出　　处：《人民长江》2021年第12期162-167,共6页Yangtze River

基　　金：中央级公益性科研院所基本科研业务费项目(CKSF2019166/JC)。

摘　　要：盐浓度在混凝土盐冻破坏过程中起着关键作用,也是影响其微观结构演化的主要因素。为研究氯盐溶液的浓度对混凝土冻融破坏的影响,并对冻融破坏进行微观尺度定量表征,通过试验对比分析了不同浓度NaCl溶液中混凝土冻融循环过程中的质量损失和相对动弹性模量变化规律,并运用压汞法测试了不同冻融次数下混凝土试件的孔隙率和孔径分布。在此基础上,结合孔结构分形维数对孔结构演化过程进行了定量表征。结果表明:在浓度约3%的NaCl溶液中混凝土冻融破坏最为严重;孔结构分形维数与混凝土冻融循环过程中的质量损失具有高度线性相关性,可以体现混凝土宏观破坏程度。Salt concentration plays a key role in the process of concrete damage during freeze-thaw cycles and is also the main factor affecting the evolution of its microstructure.To study the influence of chloride salt solution concentration on concrete freeze-thaw damage and quantitatively characterize the freeze-thaw damage on a micro scale,this article compared the mass loss and relative dynamic elastic modulus changes of concrete in NaCl solution with different concentrations during freeze-thaw cycles.The mercury intrusion method was used to test the porosity and pore size distribution of concrete with different freeze-thaw times.On this basis,the pore structure evolution process was quantitatively characterized by the pore structure fractal dimension.The results showed that the damage of freeze-thaw cycles to concrete was the most serious in NaCl solution with a concentration of about 3%,and the fractal dimension of pore structure had a high linear correlation with the mass loss of concrete in freeze-thaw cycles,which can reflect the macroscopic damage of concrete.

关 键 词：混凝土 盐冻破坏 质量损失 孔隙率 孔径分布 孔结构分形维数 冻融循环 

分 类 号：U416[交通运输工程—道路与铁道工程]