Utilizing steel slag and recycled concrete as fine aggregate could save the consumption of natural resource and reduce the environmental pollution. In this work, the effect of steel slag aggregate and recycled aggregate on the compressive strength and chloride migration coefficient of three types of concretes were investigated and compared with natural aggregate. The interfacial transition zone (ITZ) microstructure and the connection between aggregate and bulk cement matrix was determined by using a quantitative backscattered electron (BSE) image analysis, N₂ adsorption–desorption and X‐ray diffraction analysis. Results showed that the compressive strength and chloride resistance ability of natural aggregate concrete (NAC) and steel slag aggregate concrete (SAC) was highly dependent on aggregate volume content. The performance of recycled aggregate concrete (RAC) were much poorer than that of SAC and NAC. Pore structure and phase analysis confirmed that the improved properties of SAC can be partially attributed to the densified ITZ. Regarding RAC, a porous ITZ was observed in BSE image and pore structure analysis, which caused a poor compressive strength and a large chloride migration coefficient. It was found that the improvement of chloride resistance ability by using supplementary cementitious materials in NAC was more remarkable than that in SAC.

中文翻译：

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以再生钢渣为骨料的可持续混凝土界面过渡带的定量评估

以钢渣和再生混凝土为细骨料，可以节省自然资源的消耗，减少环境污染。在这项工作中，研究了钢渣骨料和再生骨料对三种类型混凝土的抗压强度和氯离子迁移系数的影响，并将其与天然骨料进行了比较。使用定量背散射电子（BSE）图像分析N ₂确定界面过渡区（ITZ）的微观结构以及骨料与本体水泥基体之间的连接吸附-解吸和X射线衍射分析。结果表明，天然骨料混凝土（NAC）和钢渣骨料混凝土（SAC）的抗压强度和抗氯化物能力高度依赖于骨料体积含量。再生骨料混凝土（RAC）的性能比SAC和NAC差得多。孔结构和相分析证实，SAC的改进特性可以部分归因于致密的ITZ。关于RAC，在BSE图像和孔结构分析中观察到了多孔的ITZ，这导致了较差的抗压强度和较大的氯离子迁移系数。发现在NAC中使用补充胶凝材料对耐氯化物能力的改善比在SAC中更为显着。