Steel corrosion can cause serious damage to reinforced concrete structures. This study employed multiple techniques, including SEM/BSE, EDX and Raman spectroscopy, to analyse the distribution and mineral composition of corrosion products (rusts) in corroded reinforced cementitious materials under two conditions, namely, chloride-induced corrosion and accelerated corrosion in carbonated mortar. Results showed that corrosion products tend to precipitate in large pore spaces close to the steel bar, such as the bleed water zones and voids. Corrosion products initially grew on the walls of these large pores and then the interior was filled with needle-like products gradually. In carbonated mortar, the length of some corrosion layers matches well the size of the coarse aggregate close to the steel. The main phases that were identified based on Roman spectra are magnetite and maghemite (after samples were exposed to atmosphere). Siderite was observed in carbonated mortars, which is not commonly found under natural conditions.

中文翻译：

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两种暴露条件下钢-混凝土界面腐蚀产物的多技术研究

钢筋腐蚀会对钢筋混凝土结构造成严重破坏。本研究采用多种技术，包括 SEM/BSE、EDX 和拉曼光谱，在氯化物诱发腐蚀和碳酸砂浆加速腐蚀两种条件下，分析了腐蚀增强胶凝材料中腐蚀产物（锈）的分布和矿物组成。 . 结果表明，腐蚀产物倾向于在靠近钢筋的大孔隙空间中沉淀，例如放水区和空隙。腐蚀产物最初在这些大孔的壁上生长，然后内部逐渐充满针状产物。在碳化砂浆中，一些腐蚀层的长度与靠近钢的粗骨料的尺寸相匹配。根据罗马光谱确定的主要相是磁铁矿和磁赤铁矿（样品暴露在大气中之后）。在碳化砂浆中观察到菱铁矿，这在自然条件下并不常见。