Calcium sulfoaluminate cement (CSA) is a low-carbon cementitious material that significantly reduces alkalinity and produces calcium hydroxide-free (CH-free) matrix environment in comparison to ordinary Portland cement (OPC). It might be, however, less efficient towards the passivation of steel in concrete and further investigation before widespread adoption is required. In this project, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) on polished samples was employed to provide the interfacial characterization of steel reinforced CSA concrete and study the relationship of interfacial quality and corrosion resistance of the embedded steel. The galvanostatic polarization behavior indicates that the steel embedded in CSA concrete remains passive for 28 days in absence of Cl⁻ ions and carbonation. Microstructure analysis has shown that there is an Al-enriched layer at interfacial zone in CSA concrete with the main hydration product of AH₃, which is also alkaline and is expected to improve the steel passivity. Furthermore, the interfacial zone has markedly reduced porosity compared to the bulk matrix, which leads to reduced possibility of current flow between anode and cathode and therefore improves the corrosion resistance of the embedded reinforcement.

中文翻译：

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CSA混凝土中钢的电化学性能及其界面组织。

硫铝酸钙水泥（CSA）是一种低碳胶凝材料，与普通的波特兰水泥（OPC）相比，可显着降低碱度并产生无氢氧化钙（CH）的基体环境。但是，在需要广泛采用之前，对混凝土中的钢进行钝化和进一步研究可能效率较低。在该项目中，使用扫描电子显微镜/能量色散X射线光谱仪（SEM / EDX）对抛光样品进行了研究，以提供CSA钢筋混凝土的界面特性，并研究了界面质量与埋藏钢的耐蚀性之间的关系。恒电流极化行为表明嵌入在混凝土CSA钢中无Cl的保持被动28天^-离子和碳酸。显微组织分析表明，在CSA混凝土的界面区域存在一个富含Al的层，其主要水合产物AH ₃也是碱性的，有望改善钢的钝化性。此外，与本体基质相比，界面区域的孔隙率显着降低，这导致电流在阳极和阴极之间流动的可能性降低，因此提高了嵌入式增强材料的耐腐蚀性。