CAREER: Model-Based Microstructure Evaluation of Hydrating Cementitous Materials: Development of a Test System and Experimental Investigation

高性能混凝土的发展对混凝土的强度和耐久性提出了上级要求。生产这些新的工程混凝土通常涉及改善混凝土的水泥相的微观结构，以实现所需的性能。高性能混凝土的成功生产产生了以下领域的研究需求：（a）开发监测和评估微观结构的方法，以及（B）对水泥相的微观结构与混凝土的强度和耐久性特征之间的关系形成基本的理解。需要提供评估水泥相的内部结构的技术和预测其材料性能发展的合理方法。维持大学高水平的研究活动需要学生的热情参与。因此，科学成就必须与教育和外联方面的进展相一致。在学术界，有必要提供一个有利于学习的环境。特别是，需要有一个环境，增加少数民族学生在工程实践和研究的参与。有必要更好地推广到少数民族学生，并增加他们在研究相关活动的参与，这个职业计划解决了双重目标：（a）推进国家的最先进的监测水泥系统的微观结构的发展和（B）提供更多的少数民族学生在研究相关活动的参与。这项研究的一个重要方面是教育和专业发展，不仅是首席研究员，但也是学生参与者和合作者从工程practice.This研究计划将开始与超声波测试程序的发展，以获得水合水泥系统的声学性能。两个主要组成部分是：（a）将声学性质与关于水化水泥系统的微观结构的信息相关联，以及（B）提供用于预测这些材料中的性质发展的合理方法。本课程将利用孔隙弹性理论，建立水泥微观结构的模型表示法。基本了解孔隙弹性理论框架内的内部结构变量与水泥系统性质（如弹性模量、强度、收缩等）之间的关系。将被研究。最后，将开发基于微观结构的房地产开发预测方法。建议的多学科研究方法涉及与化学，电气和计算机工程系的合作。研究任务涉及综合这些领域的知识和理解。少数民族学生参与本研究的整个过程中将制定在研究生，本科和高中水平。参与的学生将为进一步的学习或实践做好更好的准备，并希望他们会对研究的挑战性感到兴奋。教育推广活动专门针对纽约市哈莱姆地区的少数民族高中女生，目的是增加她们在纽约市立学院工程学课程的入学人数。将通过发表研究结果和参与国际合作研究，向更远的研究人员传播研究结果。此外，一个创新的基于网络的虚拟实验室的发展是本研究的教育组成部分的一个重要组成部分。

Requirement of high performance concrete places high demands on achieving superior performance in both strength and durability. Producing these new, engineered concretes often involves improving the microstructure of the cementitous phase of the concrete to achieve the desired properties. Successful production of high-performance concrete generates research needs in the following areas: (a) developing methods to monitor and assess the microstructure, and (b) developing a fundamental understanding of the relationship between the microstructure of the cementitous phase and the strength and durability characteristics of the concrete. Techniques that provide for assessing the internal structure of the cementitous phase and a rational way of predicting the development of its material properties are required.Sustaining high level of research activity in universities requires the enthusiastic participation of students. Therefore scientific achievements have to be concordant with advancements in education and outreach. In academia there is a need to provide an environment conducive to learning. In particular, an environment that increases the participation of minority students in engineering practice and research is required. There is a need for better outreach to the minority students and increasing their involvement in research related activities.This career plan addresses the dual objectives: (a) advance the state-of-the-art in monitoring the microstructure development in cementitous systems and (b) provide for increased participation of minority students in research related activities. An essential aspect of the study is the educational and professional development of not only the Principal Investigator, but also the student participants and collaborators from engineering practice.This research plan will commence with the development of an ultrasonic test procedure for obtaining the acoustic properties of hydrating cementitous systems. The two main components are: (a) to relate the acoustic properties with information pertaining to microstructure of a hydrating cementitous system, and (b) to provide a rational approach for predicting property development in these materials. The model-based representation of the cement microstructure will be formulated using the poroelastic theory.Fundamental understanding of the relationship between the internal structure variables within the framework of the poroelastic theory and the properties of cement systems (such as elastic moduli, strength, shrinkage etc.) will be researched. Finally, microstructure-based predictive approaches for property development will be developed.The proposed multi-disciplinary research approach involves developing collaborations with the departments of Chemistry, Electrical, and Computer Engineering. The research tasks involve synthesizing the knowledge and understanding developed in these areas. Minority student participation throughout the course of this study will be enacted at the graduate, undergraduate and high school levels. The participating students will be better prepared for further study or for practice and, it is hoped, will be excited by the challenging nature of the research. Educational outreach is specifically targeted at women minority high schools students in the Harlem area of New York City with the objective of increasing their enrollment in the engineering program at the City College of New York (CCNY). Dissemination of the study results to more distant researchers will be achieved through publishing of the results and participating in international collaborative studies. In addition, the development of an innovative web-based virtual laboratory is an essential component of this study.s educational component.