Experimental and Theoretical Studies toward the Development of New Corrosion-Resistant Steels and Corrosion Inhibitors for Reinforced Concrete Structures

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Corrosion of steel reinforcement is one of the most prevalent deterioration mechanisms in concrete structures. Annual cost of corrosion of civil infrastructure in the United States is estimated to be around $25 billion, and a large part of this amount is ascribable to steel corrosion in concrete. Therefore it is critical to develop innovative, inexpensive, and ubiquitously effective corrosion mitigation strategies in the form of new corrosion-resistant steels and corrosion inhibitors. Trial-and-error procedures to produce new and affordable materials to resist steel corrosion in concrete have been, to a large degree, ineffective. The development of these new materials has also been hindered by the gaps in the fundamental understanding of steel corrosion in concrete and the lack of tools to intelligently design and test new materials. The combined experimental and theoretical approach of the present work will provide the tools and knowledge to bridge this gap. This research will have far reaching social, political and economic impacts by enabling researchers and material developers with the fundamental tools to hypothesize, design, optimize, and test new materials to mitigate issues associated with steel corrosion in reinforced concrete structures in a cost effective way.The ultimate goal of the present research is to combine molecular dynamics simulations, first-principles calculations and experimental nano-scale material characterization techniques to make transformational contributions to the understanding of passivity and depassivation processes of steels in concrete and to create the required knowledge base and tools to develop inexpensive but highly effective new corrosion-resistant steels and corrosion inhibitors. Passivity, depassivation and corrosion of steel in concrete are atomic/molecular scale phenomena that take place within a 10-20 nanometer layer on the metal surface. Therefore, the fundamental understanding and the tools to design and test new materials need to be developed by combining nano-scale material characterization techniques and molecular level calculations. Based on the new insights provided by these techniques small, inexpensive and effective compositional changes on conventional steels can be made to increase their corrosion resistance or custom-designed corrosion inhibitors can be designed to slow down or prevent corrosion. In pursuit of these goals, the study follows a multi-disciplinary approach that brings together expertise from corrosion science, cement/concrete chemistry, electrochemistry, metallurgy, applied mathematics, numerical modeling, surface analysis and theoretical chemistry.