老混凝土中骨料-水泥界面过渡区(ITZ)(Ⅱ)——元素在界面区的分布特征

Distributions of Chemical Elements in Aggregate-Cement Interfacial Transition Zone in Old Concrete(Ⅱ)

利用电子探针 (EPXM)对骨料颗粒和水泥浆体界面过渡区 (ITZ)进行了研究。研究的重点是化学元素在 ITZ附近的分布情况。试验结果表明 :Ca、K和 Fe有不同程度地集中于界面过渡区的趋势 ,而 Si的浓度在界面处相对比较低 ,但随着远离界面其浓度逐渐升高。 Mg、Al等元素在 ITZ的局部出现 ,且有不连续分布的特点。通过对老混凝土中ITZ元素分布的分析 ,可以部分地了解混凝土内部所发生的离子和物质迁移 ,骨料和水泥浆体之间发生的化学反应 。

Electron probe X ray micro analyzer (EPXM) was employed to study the interfacial transition zone (ITZ) between the aggregate and cement matrix. Emphasis was placed on the distributions of the chemical elements in the vicinity of the ITZ. The test results showed that Ca?K and Fe tended to concentrate in the ITZ to different degrees. Si appeared to be of relatively low concentration close to the aggregate surface, but it gradually increased with the distance away from the surface. The analysis of the distributions of the chemical elements near the interface in old concrete can partially reflect the migrations of ions and substances and other interactions of the components inside the concrete. Hence, it is beneficial to the evaluations of the chemical stability and durability of the concrete.