A Thermo-Kinetic Approach to Enhance the Use of Clays in Concrete

提高粘土在混凝土中使用的热动力学方法

• 批准号: 1661609
• 负责人: Aditya Kumar
• 金额: $ 39.39万
• 依托单位: Missouri University of Science and Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1661609&HistoricalAwards=false
• 关键词: Thermo; Kinetic; Approach; Enhance; Use

In response to the incessantly increasing demand for sustainable concretes for the construction of infrastructure, past studies have identified carbon-efficient materials (e.g., fly ash, slag) for partial replacement of cement in concrete. High-volume use of these materials, however, is only beneficial when they exhibit enhanced reactivity in concrete environments. As fundamental composition-reactivity relationships for these materials are not well established, their selection is based on trial-and-error based approaches, which are unreliable and often lead to impoverished performance. Low quality and limited availability of such materials further marginalizes their adoption as construction materials. Therefore, to have a significant global impact, abundant, inexpensive, carbon-efficient, and highly reactive materials need to be identified and adapted for use in concrete. Clays, which are abundant in all geological settings, meet all of these criteria. This research aims to formulate binders for concrete by replacing up to 70% of cement with clays and other readily available inorganic materials. A holistic approach, based on accurate characterizations of reactivity, thermodynamic interactions and microstructural development, is employed to develop cost- and energy-efficient strategies to achieve enhanced reactivity of clays, including widely available low-grade clays, thus promoting their use as cement replacement materials for concrete. Overall, outcomes of this work will define a new paradigm in methods of proportioning high volumes of clay in concretes without conceding performance, thereby charting a path for widespread adoption of truly sustainable concretes. Knowledge dissemination activities, including training of underrepresented students and outreach activities to inform professionals and general audience of the economic and societal impacts of designing clay-rich sustainable concretes, will extend the impact of this research. This study employs harmonized experimental and computational tasks to elucidate fundamental composition-reactivity-microstructure-property correlations in sustainable binder systems. Advanced structure characterization and novel microcalorimetry-based reactivity-assessment techniques are used in tandem to link composition of clays to their reactivity. This knowledge is used to develop energy-efficient activation procedures that maximize the reactivity of clays, including kaolinite-deficient clays. A thermodynamic model in conjunction with experiments is used to bolster the binder?s reactivity through controlled additions of inorganic additives that synergistically interact with cement and clay to maximize the formation of space-filling reaction products. A suite of microstructure and performance characterization techniques, including a microstructure-based 3D lattice Boltzmann method, are employed to relate the microstructural evolution to the development of engineering properties. This is followed by rigorous evaluations of specification-based engineering properties of concrete made with clay-rich sustainable binders. Knowledge gained from these studies are consolidated to develop guidelines that enable selection and regulation of physical/chemical properties of clays to design sustainable concretes with enhanced properties.

为了响应对用于基础设施建设的可持续混凝土的不断增长的需求，过去的研究已经确定了碳效率材料（例如，粉煤灰、矿渣）用于部分替代混凝土中的水泥。然而，这些材料的大量使用只有在它们在混凝土环境中表现出增强的反应性时才是有益的。由于这些材料的基本组成-反应性关系没有很好地建立，它们的选择是基于试错法，这是不可靠的，并且经常导致性能差。这种材料的低质量和有限的供应进一步使其作为建筑材料的采用受到排斥。因此，为了产生重大的全球影响，需要确定并改造大量、廉价、碳效率高且反应性强的材料以用于混凝土。粘土在所有地质环境中都很丰富，符合所有这些标准。这项研究的目的是通过用粘土和其他容易获得的无机材料替代高达70%的水泥来配制混凝土粘合剂。一个整体的方法，反应性，热力学相互作用和微观结构发展的准确表征的基础上，开发成本和能源效率的策略，以实现增强的反应性粘土，包括广泛使用的低品位粘土，从而促进其作为水泥替代材料的混凝土。总的来说，这项工作的成果将定义一个新的范例，在混凝土中配比大量粘土的方法，而不放弃性能，从而为真正可持续的混凝土的广泛采用绘制了一条道路。知识传播活动，包括培训代表性不足的学生和宣传活动，以告知专业人士和一般观众的设计富含粘土的可持续混凝土的经济和社会影响，将扩大这项研究的影响。 本研究采用协调的实验和计算任务，以阐明可持续的粘结剂系统的基本组成反应性微观结构性能的相关性。先进的结构表征和新的微量热为基础的反应性评估技术被用于串联链接粘土的组合物，其反应性。这些知识被用来开发节能活化程序，最大限度地提高粘土的反应性，包括高岭石缺乏粘土。结合实验的热力学模型是用来支持粘合剂？通过控制无机添加剂的添加，与水泥和粘土协同作用，以最大限度地形成空间填充反应产物，从而提高水泥的反应性。一套微观结构和性能表征技术，包括基于微观结构的3D格子玻尔兹曼方法，涉及到微观结构的演变，工程性能的发展。随后对采用富含粘土的可持续粘结剂制成的混凝土的工程性能进行严格的评估。从这些研究中获得的知识得到巩固，以制定指导方针，使粘土的物理/化学性质的选择和调节，以设计具有增强性能的可持续混凝土。

项目成果

Effect of silica fume and slump-retaining polycarboxylate-based dispersant on the development of properties of portland cement paste

• DOI: 10.1016/j.cemconcomp.2019.03.021
• 发表时间: 2019-05-01
• 期刊: CEMENT & CONCRETE COMPOSITES
• 影响因子: 10.5
• 作者: Meng, Weina;Kumar, Aditya;Khayat, Kamal Henri
• 通讯作者: Khayat, Kamal Henri

Influence of particulate geometry on permeability of porous materials

• DOI: 10.1016/j.powtec.2019.01.064
• 发表时间: 2019-03-01
• 期刊: POWDER TECHNOLOGY
• 影响因子: 5.2
• 作者: Banala, Ajaybabu;Ma, Hongyan;Kumar, Aditya
• 通讯作者: Kumar, Aditya

Predicting compressive strength of alkali-activated systems based on the network topology and phase assemblages using tree-structure computing algorithms

• DOI: 10.1016/j.conbuildmat.2022.127557
• 发表时间: 2022-04-23
• 期刊: CONSTRUCTION AND BUILDING MATERIALS
• 影响因子: 7.4
• 作者: Bhat, Rohan;Han, Taihao;Kumar, Aditya
• 通讯作者: Kumar, Aditya

Prediction of flotation efficiency of metal sulfides using an original hybrid machine learning model

• DOI: 10.1002/eng2.12167
• 发表时间: 2020-06-01
• 期刊: ENGINEERING REPORTS
• 影响因子: 2
• 作者: Cook, Rachel;Monyake, Keitumetse Cathrine;Alagha, Lana
• 通讯作者: Alagha, Lana

Machine learning to predict properties of fresh and hardened alkali-activated concrete

• DOI: 10.1016/j.cemconcomp.2020.103863
• 发表时间: 2021-01-01
• 期刊: CEMENT & CONCRETE COMPOSITES
• 影响因子: 10.5
• 作者: Gomaa, Eslam;Han, Taihao;Kumar, Aditya
• 通讯作者: Kumar, Aditya