Stefanoni Matteo, Angst Ueli M, Elsener Bernhard
Institute for Building Materials, ETH Zurich, Stefano-Franscini-Platz 3, Zurich, CH-8093, Switzerland.
University of Cagliari, Department of Chemical and Geological Science, I-09100, Monserrato, CA, Italy.
Sci Rep. 2018 May 9;8(1):7407. doi: 10.1038/s41598-018-25794-x.
Corrosion in carbonated concrete is an example of corrosion in dense porous media of tremendous socio-economic and scientific relevance. The widespread research endeavors to develop novel, environmentally friendly cements raise questions regarding their ability to protect the embedded steel from corrosion. Here, we propose a fundamentally new approach to explain the scientific mechanism of corrosion kinetics in dense porous media. The main strength of our model lies in its simplicity and in combining the capillary condensation theory with electrochemistry. This reveals that capillary condensation in the pore structure defines the electrochemically active steel surface, whose variability upon changes in exposure relative humidity is accountable for the wide variability in measured corrosion rates. We performed experiments that quantify this effect and find good agreement with the theory. Our findings are essential to devise predictive models for the corrosion performance, needed to guarantee the safety and sustainability of traditional and future cements.
碳酸混凝土中的腐蚀是在具有巨大社会经济和科学意义的致密多孔介质中发生腐蚀的一个例子。为开发新型环保水泥而进行的广泛研究引发了关于它们保护埋入钢筋免受腐蚀能力的问题。在此，我们提出一种全新的方法来解释致密多孔介质中腐蚀动力学的科学机制。我们模型的主要优势在于其简单性以及将毛细管凝聚理论与电化学相结合。这表明孔隙结构中的毛细管凝聚决定了电化学活性钢表面，其在暴露相对湿度变化时的变化导致了测量腐蚀速率的广泛变化。我们进行了量化这种效应的实验，并发现与理论结果吻合良好。我们的研究结果对于设计腐蚀性能预测模型至关重要，而这些模型是确保传统水泥和未来水泥的安全性与可持续性所必需的。
