硫酸钠环境中混凝土界面过渡区的特点  

Characteristics of interfacial transition zone in concrete in sodium sulfate circumstance

作　　者：马德利[1,2] 詹炳根[1,2] 郑蓉美[1,2] 孙道胜[3] 盛宏玉[1,2] 

机构地区：[1]合肥工业大学土木与水利工程学院,安徽合肥230009 [2]合肥工业大学安徽土木工程结构与材料省级实验室,安徽合肥230009 [3]安徽建筑工业学院材料科学与工程学院,安徽合肥230022

出　　处：《合肥工业大学学报（自然科学版）》2011年第1期91-97,共7页Journal of Hefei University of Technology：Natural Science

基　　金：国家自然科学基金资助项目(50678058)

摘　　要：为了揭示Na2SO4等盐类易引起混凝土腐蚀和碱硅酸反应等的机理,文章研究了硫酸钠环境中混凝土界面过渡区(ITZ)的特点。外掺不同浓度Na2SO4的混凝土(水灰比0.55)在标准养护28 d后,用SEM研究了混凝土界面过渡区(ITZ)的组成与形貌,用SEM-EDS研究了界面区的元素富集,用BSE研究了界面孔结构。结果表明:加入硫酸钠后,ITZ中物相变得复杂,AFt晶体明显增多,界面区和水泥基体中有较多裂缝;随着掺入硫酸钠浓度的增大,界面区AFt的数量增加,出现硫酸钠晶体的结晶,界面区的孔隙率升高,孔径变大,结构更加疏松;界面过渡区的这些变化对混凝土的性能将产生重大影响。The characteristics of interracial transition zone（ITZ） in concrete in sodium sulfate circumstance were investigated to reveal the mechanism that salts like Na2 SO4 were liable to cause alkali-silica reaction（ASR） and sulfate corrosion in concrete. Specimens with water cement ratio of 0. 55 were incorporated with Na2SO4 with different concentrations. After the specimens were cured in standard period of 28 d, the composition and morphology of ITZ, the accumulation of elements and the pore structure in ITZ were observed via SEM, SEM-EDS, BSE respectively. The results show that the phase composition in ITZ becomes complicated： the content of ettringite（AFt） increases obviously, and many cracks exist in the ITZ and cement paste. The content of AFt in the ITZ grows with the increase of the concentration of Na2SO4, the Na2SO4 crystal occurs, and the porosity and dimension of pores in ITZ increase. These changes of the ITZ shall greatly affect the properties of concrete.

关 键 词：硫酸钠 界面过渡区 形貌 孔结构 元素分布 

分 类 号：TU528[建筑科学—建筑技术科学]