Collaborative Research: A Multi-Physics Approach to Advance Sustainable Engineering Materials

土工聚合物作为一种可持续发展的材料在结构工程应用中具有巨大的潜力。与波特兰水泥混凝土相比，地聚合物更耐用，由于使用了废弃的副产品材料，制造时能耗和资源密集度较低。然而，由于缺乏对地质聚合物形成的了解，它们的广泛采用受到了阻碍。利用非破坏性微波技术结合材料表征方法，可以研究和模拟地聚合物的反应机理，特别是涉及水的反应机理。该项目的成果将为土聚合物成为建造国家-S未来可持续结构的主要材料提供材料设计工具。这项研究还将改进对现有结构材料(如波特兰水泥混凝土)的强度、耐久性和早期性能的预测，并推动其他具有类似组成的未来材料。此外，从该项目发展出来的基于微波的评估技术将能够对现场放置后发生硬化反应的材料进行现场评估，从而提供结构健康监测和加强施工质量控制。这项工作还将包括指导不同的研究团队，并开展外联活动，以支持美洲原住民、少数民族、女性和本科生的成功。这项研究将促进对地质聚合物反应机理的基本理解，这对促进可行的地质聚合物组合物用作可持续结构材料至关重要。微波技术将被用来通过介电测量来识别材料性质的变化。介电混合模型将用多尺度材料表征技术来证实，以量化水结合的变化和相应的地质聚合物中的相组成转变。这种多物理方法最终将产生两种新的材料模型。第一个模型将地聚反应中的相形成机制与凝结、流变性和力学行为联系起来。第二个模型将水泥水化的幂模型扩展到碱激发材料。这样的模型将使材料工程师能够根据组成和固化投入来优化地质聚合物微结构。这些模型可以推广到具有硅酸钙化学和可变水结合的其他材料。这项工作还将为适用于评估地聚合物成熟度的现场测试方法奠定基础，从而提供结构健康监测和改进的质量控制。

Geopolymers have tremendous potential to be used as a sustainable material for structural engineering applications. Compared to portland cement concrete, geopolymers are more durable and less energy- and resource-intensive to manufacture due to their use of waste by-product materials. However, their widespread adoption is hindered due to a lack of understanding about geopolymer formation. Using a nondestructive microwave technique coupled with materials characterization methods, geopolymer reaction mechanisms can be studied and modeled, especially those involving water. The outcomes of the project will provide material design tools for geopolymers to become a staple material used to build the nation?s future sustainable structures. This research will also improve the prediction of strength, durability, and early-age properties of current structural materials such as portland cement concrete and advance other future materials with similar compositions. Further, the microwave-based assessment technique evolved from this project will enable in-situ evaluation of materials that undergo a hardening reaction after placement in the field thereby offering structural health monitoring and enhancing the construction quality control. This work will also include mentoring a diverse team of researchers and development of outreach activities that support the success of Native American, minority, female, and undergraduate students.This research will advance the fundamental understanding of geopolymer reaction mechanisms, which is critical for the advancement of viable geopolymer compositions for use as sustainable structural materials. Microwave techniques will be used to discern changes in material properties through dielectric measurements. Dielectric mixing models will be corroborated with multi-scale materials characterization techniques to quantify changes in water binding and corresponding phase composition transformations in geopolymers. This multi-physics approach will culminate in two new material models. The first model will link the phase formation mechanisms that occur during geopolymerization reaction with setting, rheological, and mechanical behavior. The second model will extend Powers Model for cement hydration to alkali-activated materials. Such a model will allow materials engineers to optimize geopolymer microstructures based on composition and curing inputs. These models can be extended for other materials with calcium-silicate chemistries and variable water binding. This work will also lay the groundwork for in-situ test methods suitable for assessment of geopolymer maturity, thereby offering structural health monitoring and improved quality control.