CAREER: Taking Sustainable Cements to the Next Level: New Routes to Control and Amplify the Chemical Reactivity of Cementing Phases

该学院早期职业发展（Career）项目设计了具有增强反应性的波特兰水泥，从而大大提高了水泥在混凝土中的使用效率。通过操纵：(1)杂质分布（即客体离子）和(2)通过水泥合成的热处理（例如淬火）路线，可以引起反应性放大。这些操作诱发水泥矿物的结构缺陷，从而提高其反应性。利用密度泛函理论和分子动力学计算，通过纯水泥相及其固溶体的合成，以及相溶解速率的纳米尺度测量，研究了从量子到连续统尺度的反应性。这些研究被组织起来进行计算和实验，以相互作用，并通过详细考虑相化学、性质和加工来指导高活性固井相的发现。这项研究的重点是反应性，使用少量的高活性水泥生产混凝土，其性能相当于今天使用大量传统水泥生产的混凝土。因此，通过减少混凝土中水泥的使用/浪费，保守地说，这项工作的结果是全球水泥（和二氧化碳排放）节约约15%，即约5亿吨。这是减少水泥使用的一个转化范例，它将从根本上改变建筑行业从材料角度看待可持续性的方式。该项目开发了从高中生到博士后科学家等各个科学成熟度层次的毕业培训。加州大学洛杉矶分校的多样性和高中参与平台被用来为经济状况不佳的少数族裔候选人提供研究机会，而洛杉矶高中的教育工作者、YouTube和Facebook的企业则被用来激发对年轻科学家的兴趣，并为他们提供成长机会。

This Faculty Early Career Development (CAREER) project engineers portland cements having enhanced reactivity, so as to substantially enhance efficiencies associated with the use of cement in concrete. Reactivity amplifications are provoked by manipulating: (1) impurity distributions (i.e., guest ions) and (2) thermal processing (e.g., quenching) routes through cement synthesis. These manipulations induce structural imperfections in cement minerals, and thus act to elevate their reactivity. Reactivity is studied across quantum-to-continuum scales using density functional theory and molecular dynamics calculation, by synthesis of pure cement phases and their solid solutions, and by nanoscale measurements of phase dissolution rates. The investigations are organized for calculation and experiment to interact with each other, and guide the discovery of highly reactive cementing phases through detailed considerations of phase chemistry, properties and processing.This research places emphasis on reactivity, to produce concretes using a smaller quantity of highly reactive cement, which are performance-equivalent to concretes produced today using larger quantities of traditional cements. Thus, by reducing the use/wastage of cement in concrete, the outcomes of the work conservatively target global cement (and CO2 emissions) savings of around 15%, i.e., around 500 million tons. This is a translational paradigm in reducing cement use, which will radically alter how sustainability is approached from a materials perspective by the construction industry. The project develops graduated training across levels of scientific maturity, from high-school students to post-doctoral scientists. Diversity and high-school engagement platforms at UCLA are leveraged to provide research opportunities to financially disadvantaged minority candidates, while LA-high-school educators and YouTube and Facebook ventures are engaged to incite interest in, and provide growth opportunities to young scientists.