Collaborative Research: Fundamental Studies on Composition-Microstructure-Performance Relationships of Sustainable Cementitious Binders

这项研究的动机是开发真正可持续的混凝土的长期需求，以减少40- 70%的水泥（质量基础），显示出与纯水泥相当的早期/后期性能。因此，将开发多种材料解决方案，以优化使用丰富的天然材料，如石灰石（粉末），以生产水泥含量大大降低的混凝土。科学的方法是利用碳铝酸盐相的形成来确保反应产物的固体体积的增加和孔隙率的降低，当有利的粘合剂化学存在时。热力学计算将用于预测改性粘合剂系统的平衡固/液相组合。计算将通过动力学、微观结构和相表征研究进行验证。对物理和工程性质的进一步评估将用于开发性质预测的分析工具。具体而言，将评估与机械和运输行为相关的方面，以开发材料模型，该模型将微观结构的物理方面和整体粘合剂化学与实际建筑应用相关的工程特性联系起来。化学成分-微观结构-工程性能关系的发展将使性能预测工具的进步，从而确保这些混凝土在混凝土施工应用中的广泛使用。这项研究的结果将使具有理想工程性能的下一代可持续混凝土材料的开发和部署成为可能，并为其预测提供工具，从而为结构设计师、承包商和混凝土生产商提供广泛指定和部署可持续、低二氧化碳建筑材料解决方案所需的信心。这一点很重要，因为促进低水泥含量混凝土的使用将改变混凝土建筑行业从材料角度考虑可持续性指标的方式。从教育的角度来看，这项研究将支持在合作院校培训代表性不足和少数民族的博士和本科生。将通过科学出版物和报告、工业讲习班和专业教育课程，迅速向更广泛的研究和实践界传播这项研究。

This research study is motivated by the long-term need to develop truly sustainable concretes for a cement reduction target of 40-70 percent (mass-basis) that demonstrate early/later age properties comparable to their pure-cement counterparts. As such, multiple-material solutions will be developed to optimize the use of abundant, naturally occurring, materials such as limestone (powder) to produce concretes with highly reduced cement contents. The scientific approach exploits carboaluminate phase formation to ensure an increase in the solid volume of reaction products and a reduction in the porosity, when a favorable binder chemistry exists. Thermodynamic calculations will be used to predict the equilibrium solid/liquid phase assemblages of the modified binder systems. The calculations will be validated against kinetic, microstructural and phase characterization studies. Further evaluations of the physical and engineering properties will be carried out to develop analytical tools for property prediction. Specifically, aspects related to the mechanical and transport behavior will be evaluated to develop material models which relate the physical aspects of the microstructure and the overall binder chemistry to the engineering properties as relevant for practical construction applications. The development of chemical composition-microstructure-engineering property relationships will enable the advancement of property prediction tools and thus ensure the wide-spread use of these concretes in concrete construction applications.The outcomes of this research will enable the development and deployment of the next generation of sustainable concrete materials with desirable engineering properties and provide tools for their prediction thus providing structural designers, contractors and concrete producers the confidence needed to widely specify and deploy sustainable, low-CO2 construction material solutions. This is significant as facilitating the use of concretes with a low-cement content will change the way sustainability metrics are considered from a materials perspective in the concrete construction industry. From an educational perspective, this research will support the training of under-represented and minority Ph.D and undergraduate students at the collaborating institutions. Rapid dissemination of the research to the broader research and practicing community will be accomplished through scientific publications and presentations, industrial workshops and professional education courses.