Understanding Rheology of Cement-based Materials through Intergrated Experiments and Computations at Multiple Scales

本项目的目的是建立一个预测水泥基材料流变性能的预测模型。该模型采用浸入边界法（IBM）-离散元法（DEM）耦合，将单个颗粒的行为与水泥基材料在多个尺度上的整体流变行为联系起来。主要研究工作包括：（1）利用原子力显微镜（AFM）实验对耦合的IBM-DEM模型进行校准/验证，并捕获水泥体系中的颗粒间相互作用（2）建立精细耦合的IBM-DEM模型，预测水泥浆体在简单剪切流场中的体相流变行为（3）通过各种水泥浆体的流变实验（中尺度和宏观尺度）评估模型的预测能力。这种研究方法/方法将最终导致更好的宏观模型的混凝土在未来。通过实验、理论和建模，该项目将更好地理解水泥基材料的流变行为。所开发的模型将允许更经济的设计，通过优化配合比在混凝土实践中指定的流变要求。水泥工业可利用颗粒相互作用的信息，在水泥生产过程中改变水泥的化学和物理性能。拟议的工作需要混凝土材料，多相流建模，纳米表面工程和力学的跨学科知识，因此，学生将在本项目期间接受各种补充研究技术的培训。

The objective of this proejct is to develop a predictive model for predicting rheological behavior of cement-based materials. Using a coupled immersed boundary method (IBM) - discrete element method (DEM), the model will link individual particle behavior to the bulk rheological behavior of cement-based materials at multiple scales. The major research activities will include (1) utilizing atomic force microcopy (AFM) experiments to calibrate/validate a coupled IBM-DEM model and to capture the interparticle interactions in a cement system (nanoscale); (2) establishing a refined coupled IBM-DEM model to predict bulk rheological behavior of a cement paste in simple shear flow (mesoscale); and (3) assessing the predictive capability of the model via rheological experiments of various cement pastes (meso and macro scales). This research approach/methodology will eventually lead to better macroscale models of concrete in future. Through experiments, theory and modeling, the project will provide a better understanding of the rheological behavior of cement-based materials. The developed model will permit more economical designs by optimizing mix proportions for specified rheological requirements in concrete practice. The information on the particle interaction can be adapted by the cement industry for modifying cement chemistry and physical properties during the cement manufacturing process. The proposed work requires interdisciplinary knowledge in concrete materials, multiphase flow modeling, and nanoscale surface engineering and mechanics, and therefore, students will be trained in a variety of complementary research techniques during this project.