不同集料界面过渡区对氯离子传输特性的影响

In order to investigate the influence of interfacial transition zone on chloride transport performance, fine natural aggregate concrete, fine steel slag aggregate concrete and fine recycled aggregate with different aggregate volume fractions were prepared. Back scattered electron (BSE) image quantitative analysis, X-ray diffraction (XRD) phase determination, chloride migration coefficient test and simulated pore solution test were applied to study the microstructure characteristics of the interfacial transition zone(ITZ) in concrete made with fine steel slag aggregate and fine recycled aggregate and its influence on concrete performance. The results show that the steel slag aggregate possesses hydration activity, and its hydration product connects the aggregate with cement matrix, which makes the ITZ porosity in steel slag aggregate concrete lower than those of natural aggregate concrete and recycled aggregate concrete. Therefore, the fine steel slag aggregate concrete has a relatively low chloride migration coefficient. The ITZ in fine recycled aggregate concrete is more porous and has different types, resulting in the much higher chloride migration coefficient of fine steel slag aggregate concrete than those of the other two fine aggregate concretes.