CAREER: Towards Perpetually Limited Corrosion of Steel in Concrete with Tailored Interfaces

该学院早期职业发展奖将支持旨在最大化钢筋混凝土基础设施的可持续性和耐久性的综合研究和教育努力。钢筋的腐蚀仍然是钢筋混凝土耐久性的一个限制因素，阻碍了新型的、以其他方式耐用的二氧化碳消耗水泥和混凝土的使用。该项目将确定最佳的钢材和混凝土界面条件，以永久限制氯离子影响的腐蚀损害，同时考虑到传统和可持续的替代混凝土混合料配方。这项研究工作将与一个教育目标相结合，以提高土木工程专业学生和从业者解决民用基础设施中经常被忽视的腐蚀耐久性问题的能力。将利用高中生的研究经验，提高未被充分代表的群体对STEM职业的兴趣。通过国际公认的腐蚀组织发布和管理的腐蚀损害预测模块将为负责确保土木工程基础设施耐久性的土木工程从业者提供知识基础和技能集。研究目标是考虑到钢筋和混凝土界面的条件，描述混凝土内钢筋腐蚀的多尺度演变。腐蚀从局部的小坑开始，这些坑可以生长并积累成更广泛的腐蚀损害。然而，在某些条件下，凹坑可以通过再钝化过程停止生长。该项目的目标是：1)确定促进氯离子引起的点蚀再钝化所需的钢和混凝土界面条件；2)建立控制凹坑形状演变和损伤发展的机制；3)基于根据暴露测试结果校准的多尺度损伤预测模型，确定最佳的耐腐蚀界面条件。界面条件促进局部凹坑再钝化的能力将根据单凹坑生长实验测量的凹坑稳定性系数来量化，其中考虑了由于湿度水平和粘结剂配方的多孔反应性质而造成的阴极限制。考虑到钢-混凝土界面的质量，分裂双极电化学与多物理模型相结合将产生凹坑生长动力学和形状演变。多尺度腐蚀损伤预测模型可以模拟局部点蚀向宏观腐蚀损伤的转变，以提供考虑传统和新型固碳混凝土配方的最优界面条件，以最大限度地提高腐蚀耐久性。这项工作的结果将有助于为钢筋混凝土基础设施的永久有限腐蚀设计制定基于性能的规范。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development (CAREER) award will support integrated research and education thrusts aimed at maximizing the sustainability and durability of reinforced concrete infrastructure. Corrosion of steel continues to be a limiting factor in the durability of reinforced concrete and has prevented the use of novel and otherwise durable carbon-dioxide consuming cement and concrete. This project will identify optimal steel and concrete interface conditions that can perpetually limit chloride influenced corrosion damage considering both traditional and sustainable alternative concrete mixture formulations. The research effort will be integrated with an education goal to improve the ability of civil engineering students and practitioners to address often overlooked corrosion durability issues in civil infrastructure. Research experiences for high school students will be used to enhance interests in STEM careers among underrepresented groups. Corrosion damage forecasting modules disseminated and administered through an internationally recognized corrosion organization will provide a knowledge foundation and skill set to civil engineering practitioners tasked with ensuring the durability of civil infrastructure.The research objective is to characterize the multi-scale evolution of steel corrosion within concrete considering the condition of the steel and concrete interface. Corrosion starts as small, localized pits that can grow and accumulate into more widespread corrosion damage. However, under some conditions the pits can stop growing by the process of repassivation. The project aims to: 1) identify steel and concrete interface conditions required to promote repassivation of chloride-induced pitting corrosion, 2) establish the mechanisms controlling pit shape evolution and damage progression, and 3) identify optimally corrosion resistant interface conditions based on multi-scale damage forecasting models calibrated to exposure testing results. The ability of the interface condition to promote repassivation of localized pits will be quantified according to pit stability coefficients measured by single pit growth experiments accounting for cathodic limitations due to moisture levels and the porous-reactive nature of binder formulations. Split bipolar electrochemistry coupled with a multi-physics model will yield pit growth kinetics and shape evolution considering the quality of the steel and concrete interface. A multi-scale corrosion damage forecasting model that can simulate the transition of localized pitting corrosion to macro-scaled corrosion damage will be used to inform optimal interface conditions that maximize corrosion durability considering traditional and novel carbon-sequestering concrete formulations. The results of this work will enable the development of performance-based specifications for the design of perpetually limited corrosion of reinforced concrete infrastructure.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.