CAREER: Antiquity-Inspired Novel Stratlingite-Based Cementitious Binder (StraCem): A Lesson from Ancient and Modern Civilizations

职业：受古代启发的新颖的基于 Stradlingite 的水泥基粘结剂 (StraCem)：古代和现代文明的教训

• 批准号: 2239511
• 负责人: Monday Okoronkwo
• 金额: $ 67.48万
• 依托单位: Missouri University of Science and Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2239511&HistoricalAwards=false
• 关键词: CAREER; Antiquity; Inspired; Novel; Stratlingite

This Faculty Early Career Development (CAREER) award will advance the fundamental understanding of the kinetics and thermodynamics of stratlingite precipitation and its interaction with calcium silicate hydrate phases, to enable the design of a new eco-efficient stratlingite-based cementitious binder (StraCem) that mimics the chemistry and mineralogy of ancient Roman concretes, while integrating the benefits of modern concrete designs. Many ancient structures have withstood aggressive seawater environments for over 2000 years testifying to their high durability and resilience, while most modern structures tend to deteriorate slowly under similar environments. However, modern concrete technology enables the design of concretes for specific applications with impressive properties that were not possible in the ancient era. The performance and durability of concretes are known to be strongly linked to the chemistry and microstructure of the hardened matrix, and recent studies have disclosed the mineral phase assemblage and microstructure of existing Roman structures, wherein the distribution of tobermorite-like calcium silicate hydrate and stratlingite phases are postulated to be contributory to their durability and resilience. This project will harness the chemistries of ancient concretes and modern ones to facilitate the design of StraCem that features at least 50% lower carbon footprint than Portland cement, while ensuring superior performance, chemical resilience, and durability in land and marine environments. The lower carbon footprint of the materials contributes to the mitigation of climate change. The program integrates educational activities to help inspire, train, and equip future cement material scientists and engineers through local K-12 outreach activities, provision of experiential learning opportunities for underrepresented minority undergraduate and graduate students, and the outcome of the study will enrich new and existing courses on the chemistry of cement-based materials. The specific research goal of this project is to investigate the pathways and energetics of stratlingite nucleation and growth together with tobermorite-like calcium silicate hydrate gels in cementitious systems. The effort will unlock the compositional drivers, including aqueous pore solution chemistries, and the energy landscapes to facilitate rapid coprecipitation of stable stratlingite and Al-tobermorite-like calcium silicate hydrate gels. The study will be curated with relevant nucleation and growth theories, and the insight thereof will be applied to design a novel low-carbon StraCem clinker that will yield an optimum balance of stratlingite and calcium silicate hydrate gel during hydration, mimicking reported beneficial mineralogy of ancient Roman concretes, while minimizing less beneficial hydrate phases. The performance and durability of the designed StraCem-based pastes, mortars, and concretes will be investigated in air and simulated marine conditions. It is hypothesized that StraCem will feature superior performance and durability than Portland cement under terrestrial and marine environments, due to the space-filing properties of strätlingite and binding ability of calcium silicate hydrate gel. Also, the new cement will present significantly lower CO2 emissions due to its lower calcareous content and clinkering temperature than Portland cement. To actualize the objectives, a combination of wet chemistry, solid-state chemistry, in-situ and ex-situ multiscale characterization, and thermodynamic computation will be employed. This project will establish multi-disciplinary research and mentorship at the intersection of chemistry, chemical engineering, materials science, and civil engineering.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.

这个学院早期职业发展（Career）奖将促进对平层石沉淀的动力学和热力学的基本理解，以及它与硅酸钙水合相的相互作用，使设计一种新的生态高效的基于平层石的胶凝粘合剂（StraCem）能够模仿古罗马混凝土的化学和矿物学，同时整合现代混凝土设计的好处。许多古代建筑在恶劣的海水环境下经受了2000多年的考验，证明了它们具有很高的耐久性和弹性，而大多数现代建筑在类似的环境下往往会缓慢退化。然而，现代混凝土技术使混凝土的设计具有令人印象深刻的性能，在古代是不可能的具体应用。众所周知，混凝土的性能和耐久性与硬化基质的化学和微观结构密切相关，最近的研究揭示了现有罗马结构的矿物相组合和微观结构，其中托贝莫里石样水合硅酸钙和层状石相的分布被认为有助于它们的耐久性和弹性。该项目将利用古代混凝土和现代混凝土的化学成分来促进StraCem的设计，其碳足迹至少比波特兰水泥低50%，同时确保卓越的性能、化学弹性和在陆地和海洋环境中的耐久性。材料的低碳足迹有助于减缓气候变化。该项目整合了教育活动，通过当地的K-12外展活动，为未被充分代表的少数民族本科生和研究生提供体验式学习机会，帮助激励、培训和装备未来的水泥材料科学家和工程师，研究结果将丰富新的和现有的水泥基材料化学课程。本项目的具体研究目标是研究层状石在胶凝体系中与托贝莫来石样水合硅酸钙凝胶一起成核和生长的途径和能量学。这项工作将解开组成驱动因素，包括水孔隙溶液化学，以及能量景观，以促进稳定的stratlingite和al -tobermorite类水合硅酸钙凝胶的快速共沉淀。该研究将结合相关的成核和生长理论，并将其见解应用于设计一种新型低碳StraCem熟料，该熟料将在水化过程中产生最佳平衡的stratlingite和水化硅酸钙凝胶，模仿报道的古罗马混凝土的有益矿物学，同时最大限度地减少不有益的水合物相。设计的基于stracem的浆料、砂浆和混凝土的性能和耐久性将在空气和模拟海洋条件下进行研究。据推测，由于strätlingite的空间填充特性和水合硅酸钙凝胶的结合能力，StraCem在陆地和海洋环境下将比波特兰水泥具有更好的性能和耐久性。此外，与波特兰水泥相比，新型水泥的钙质含量和熟化温度较低，因此二氧化碳排放量显著降低。为了实现这些目标，将结合湿化学、固态化学、原位和非原位多尺度表征以及热力学计算。该项目将建立化学、化学工程、材料科学和土木工程交叉学科的研究和指导。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。