A mechanistic approach for predicting the service life & performance of steel reinforced concrete bridge becks

当今世界面临的重大问题之一是基础设施的老化。世界各地保护和修复混凝土结构的成本是一个巨大且日益严重的问题(每年支出超过1000亿美元)。这种腐蚀的一个主要组成部分是由于埋入的钢筋的腐蚀而导致桥梁和高速公路的退化。这一问题促使了各种替代策略的发展，以延长暴露在恶劣环境中的钢筋混凝土结构的使用寿命。在最广为人知的程序中，可以提到：化学防腐剂、钢筋上的保护涂层、耐腐蚀钢(不锈钢、MMFX等)、混凝土裸露表面的防水膜或密封剂、阴极保护、高性能混凝土等。最佳的设计/维修策略不仅需要对前期成本进行估计，而且还需要将所有相关成本与可能延长结构寿命的情况进行比较。当考虑到新开发的材料(如不锈钢、MMFX和玻璃钢复合材料)时，这个问题最难回答，因为缺乏关于它们现场性能的历史数据。在这种情况下，根据第一原则，机械化的方法已被证明是在以前未经测试的条件下做出可靠预测的非常强大的工具。拟议研究的主要目标是利用先进的理论和实验技术，包括基于同步加速器的测试方法，为可靠的寿命预测开发可靠的机械模型。位于S大学校园的加拿大光源(国家同步加速器设施：http://www.lightsource.ca))的存在为对材料进行前所未有的高分辨率显微分析提供了机会。同步加速器光覆盖了光谱的所有范围；允许比以往任何时候都更准确和精确；并允许在一般环境条件(湿度、化学反应等)下实时探测物质。

One of the significant problems facing the world today is the decay of infrastructure. The cost of protecting and restoring concrete structures worldwide is a large and growing problem (more than $100 billion in annual expenditures). A major component of this decay is the degradation of bridges and highways due to corrosion of the embedded reinforcing steel. This problem has prompted the development of a variety of alternative strategies for increasing the service life of reinforced concrete structures exposed to harsh environments. Among the most well known procedures, one can mention: chemical corrosion inhibitors, protective coatings on steel reinforcement, corrosion-resistant steels (stainless steels, MMFX, etc.), waterproofing membranes or sealants applied to the exposed surface of the concrete, cathodic protection, high performance concrete etc. Each of these alternative technologies has different technical merits and costs associated with their use. An optimum design/repair strategy requires not only an estimate of upfront costs, but also the means to compare all associated costs against the potential extension to the life of the structure. This issue is hardest to answer when considering newly developed materials (such as stainless steels, MMFX, and FRP composites) because of a lack of historical data about their field performance. In such situations, based on first principles, mechanistic approaches have proven to be very powerful tools for making reliable predictions under previously untested conditions. The main objective of the proposed research is to develop sound mechanistic models for reliable service life predictions using advanced theories and experimental techniques, including synchrotron-based testing methods. The presence of the Canadian Light Source (the national synchrotron facility: http://www.lightsource.ca) on the U of S campus provides the opportunity to conduct unprecedented high resolution microscopic analyses of materials. Synchrotron Light covers the full range of the light spectrum; allows greater accuracy and precision than has ever before been possible; and allows matter to be probed in real time under general environmental conditions (moisture, chemical reactions, etc.)