Collaborative Research: Measuring, Monitoring, and Modeling the Setting Properties of Concrete

这个项目是路易斯维尔大学和西北大学研究小组的合作成果。为了保证材料的高质量，避免材料的寿命性能出现问题，本研究旨在研究和了解先进水泥基材料在凝结过程中演变的纳米/微结构与力学性能之间的基本关系。首先，研究将集中于利用各种新开发的测量技术在不同尺度上表征不断演变的纳米/微结构。第二，将开发能够在此期间连续监测相应材料性能的现场技术。第三，建立基于测量和监测的多尺度模型，预测初凝时间、粘度和化学收缩等材料行为，这些都是混凝土结构施工的重要质量控制参数。这些宏观结构参数与微观结构参数，如颗粒堆积、固体浓度、固体絮凝、固体渗流和化学水化等之间的关系将被研究。本研究提出了一种主要从物理角度来识别材料性质的创新方法。将研究混凝土纳米/微观结构的测量、监测和建模技术，以扩展和改进混凝土材料特性在设定过程中的当前知识状态。这项研究的结果将有助于开发可靠的质量控制方法，在非常早期监测混凝土结构，这将使预拌工厂、承包商、水泥厂、化学外加剂公司以及地方和联邦政府机构受益。

This project is a collaborative effort between research groups from University of Louisville and Northwestern University. In order to assure high quality, and to avoid problems in the lifetime performance of the material, the study aims at investigating and understanding the fundamental relationships among evolving nano/micro-structures and mechanical properties during the setting period of advanced cement-based materials. First, the research will focus on characterizing evolving nano/micro-structures with various newly-developed measuring technologies on different scales. Second, in-situ techniques that can continuously monitor the corresponding material properties during this period will be developed. Third, a multi-scale model based on measuring and monitoring will be established to predict material behaviors such as initial setting time, viscosity, and chemical shrinkage, which are important quality control parameters for the construction of a concrete structure. The correlations between these macro-structural parameters and micro-structural parameters, such as particle packing, solid concentration, solid flocculation, solid percolation, and chemical hydration, will be investigated. Thus, the characterization of intrinsic material properties can be explicit.This research presents an innovative approach to the identification of material properties from a primarily physical point of view. Techniques for measuring, monitoring, and modeling the nano/micro-structure of concrete will be examined to expand and improve the current state of knowledge of concrete's material properties during setting. The results of this research will facilitate the development of reliable quality control methods for monitoring concrete structures at very early ages, which should benefit ready-mix plants, contractors, cement plants, chemical admixture companies, and local and federal government agencies.