氯离子诱发混凝土中钢筋锈蚀的锈蚀层分析

姬永生^{1, 2}，张领雷²，马会荣²，王志龙²，周敏²

(1. 中国矿业大学 深部岩土力学与地下工程国家重点实验室，江苏 徐州，221008；
2. 中国矿业大学 力学与建筑工程学院，江苏 徐州，221008)

摘 要：通过X线衍射、扫描电镜和电子探针等微观测试技术研究混凝土中钢筋锈蚀产物的物相组成和微观结构。研究结果表明：混凝土中钢筋的锈蚀层是铁锈和水泥凝胶体的混合物，钢筋的锈蚀产物由针铁矿α-FeO(OH)、四方纤铁矿β-FeO(OH)、纤铁矿γ-FeO(OH)、赤铁矿α-Fe₂O₃、磁赤铁矿γ-Fe₂O₃、磁铁矿Fe₃O₄、和方铁矿FeO等相组成；锈蚀钢筋表面有较多的锈蚀凹坑和密集的锈蚀麻点，是由大面积的均匀腐蚀与稀疏的局部点蚀共同组成的全面锈蚀；钢筋的锈层结构分为内外两层，外锈层结构疏松，而内层结构致密，与钢筋基体紧密相连。

关键词：锈蚀层；物相组成；微细观结构；元素分布

Analysis on rusts of steel bar in concrete exposed to chloride-containing environment

JI Yong-sheng^{1, 2}, ZHANG Ling-lei², MA Hui-rong², WANG Zhi-long², ZHOU Min²

(1. State Key Laboratory for Geomechanics and Deep Underground Engineering,
China University of Mining and Technology, Xuzhou 221008, China;
2. School of Mechanics & Civil Engineering, China University of Mining and Technology, Xuzhou 221008, China)

Abstract:Several experimental techniques such as X-ray diffraction, SEM and EDXA were used to study the corrosion products and submicroscopic structure formed on steel rebars embedded in concrete. The results show that the product layer is composed of calcium silicate hydrate phases mixed with Fe oxides near the steel-matrix interface of cement system. The phase components of the rust are goethite, akageneite, lepidocroeite, hematite, maghemite, magnetite and wustite. Several smaller pits lying in a larger pit and some islet-like dissipated iron particles in the rusts show that the corrosion failure of rebar is caused by uniform corrosion and pitting corrosion. The micro-structural investigation shows that the rust is composed of two layers: a dense inner one firmly adhered to the substrate, and a porous outer one of the final steel corrosion products.

Key words:rusting layer; corrosion products composition; submicroscopic structure; elements distribution