Multiscale Mechanisms of Dissolution and Reactivity of Calcium Aluminosilicate Glasses: Towards Rational Design of Low-Carbon Cement Substitutes

水泥是混凝土的粘合剂，是世界上使用最广泛的人造材料，占全球碳排放量的5%左右。因此，取代混凝土中的水泥已成为减轻混凝土行业对环境影响的最有效策略之一。该项目的目的是利用计算机模拟和实验测试，制定基于物理的指导方针，以推进低碳水泥替代材料的设计。目前可用的低碳水泥替代品反应缓慢，随着主要供应行业出于环境原因逐步淘汰，其供应量继续下降。预测和设计低碳水泥替代品的反应性的能力仍然有限，因为对控制这些反应的基本机制缺乏了解。本研究的目的是提供基本的洞察到的多尺度机制，管理的反应性的钙铝硅酸盐玻璃，这是主要的反应相在水泥替代材料。还将执行与当地非营利伙伴合作制定的全面外联计划。推广计划的重点是促进K-12学生的科学素养和环境领导力，特别是那些来自STEM中服务不足的社区和代表性不足的少数民族的学生。本研究的目的是发展的钙铝硅酸盐玻璃作为玻璃结构和组成的函数的溶解和反应性的基本理解。这项研究将结合联合收割机的多尺度框架的基础上密度泛函理论，分子动力学和动力学蒙特卡罗模拟，连同玻璃表征，溶解测量和反应性测试。这种混合方法将弥合分子水平上理解玻璃反应性和实验中测量的宏观反应性之间的差距。这项研究将产生以下成果：（1）在分子水平上完全表征钙铝硅酸盐玻璃的反应性谱，（2）在介观尺度上基本理解控制钙铝硅酸盐玻璃溶解行为的机制，和（3）全面理解玻璃结构/组成，溶解，和反应性。这项工作的结果将揭示无序材料的反应性，这具有广泛的跨学科应用，并将为高活性低碳水泥替代品的合理设计铺平道路，这是迈向可持续混凝土的关键一步。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Cement, the binding agent of concrete, is the most widely used human-made material worldwide and is responsible for about 5 percent of global carbon emissions. Replacing cement in concrete has therefore emerged as one of the most effective strategies to mitigate the environmental impact of the concrete industry. The aim of this project is to formulate physics-based guidelines, using computer simulations and experimental testing, to advance the design of low-carbon cement substitute materials. Currently available low-carbon cement substitutes exhibit slow reactivity, and their availability continues to decline as the key supplier industries are phasing out for environmental reasons. The ability to predict and design the reactivity of low-carbon cement substitutes remains limited because of the poor understanding of the basic mechanisms that govern these reactions. This research aims to provide fundamental insight into the multiscale mechanisms that govern the reactivity of calcium aluminosilicate glasses, which are the main reactive phases in cement substitute materials. A comprehensive outreach plan developed in collaboration with local non-profit partners will also be implemented. The focus of the outreach plan is to promote scientific literacy and environmental leadership among K-12 students, especially those from underserved communities and underrepresented minorities in STEM. The goal of this research is to develop a fundamental understanding of the dissolution and reactivity of calcium aluminosilicate glasses as a function of glass structure and composition. The research will combine a multiscale framework based on density functional theory, molecular dynamics, and kinetic Monte Carlo simulations, together with glass characterization, dissolution measurements, and reactivity testing. This hybrid approach will bridge the gap between molecular-level understanding of glass reactivity and macroscopic reactivity measured in experiments. This research will result in the following outcomes: (1) full characterization of the reactivity spectrum of calcium aluminosilicate glasses at the molecular level, (2) fundamental understanding of the mechanisms that govern the dissolution behavior of calcium aluminosilicate glasses at the mesoscale, and (3) comprehensive understanding of the relationship between glass structure/composition, dissolution, and reactivity for a wide range of glass compositions. The findings from this work will shed light into the reactivity of disordered materials, which has broad cross-disciplinary applications, and will pave the way for the rational design of highly reactive low-carbon cement substitutes, a key step towards sustainable concrete.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.