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

这项研究研究的动机是长期需要开发真正可持续的混凝土，以实现水泥减量40%-70%(质量基础)的目标，这些混凝土表现出与纯水泥相当的早期/晚龄期性能。因此，将开发多种材料解决方案，以优化使用丰富的自然产生的材料，如石灰石(粉末)，以生产水泥含量极低的混凝土。当存在有利的粘结剂化学时，科学方法利用碳铝酸盐相的形成来确保反应产物的固体体积增加和孔隙率减少。热力学计算将用于预测改性粘结剂体系的平衡固/液相组合。这些计算将通过动力学、微观结构和物相表征研究进行验证。将对物理和工程性质进行进一步评估，以开发财产预测的分析工具。具体地说，将评估与机械和运输行为相关的方面，以开发材料模型，将微观结构和整体粘结剂化学的物理方面与实际建筑应用相关的工程特性联系起来。化学组成-微观结构-工程性能关系的发展将促进性能预测工具的进步，从而确保这些混凝土在混凝土建筑应用中的广泛使用。这项研究的成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。这一点意义重大，因为促进低水泥含量混凝土的使用将改变混凝土建筑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机构培养代表不足和少数族裔的博士和本科生。将通过科学出版物和演讲、工业研讨会和专业教育课程，将研究成果迅速传播到更广泛的研究和实践社区。

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.