Materials World Network: Effects of Precursor Nanostructure on Geopolymer Structure and Properties

材料世界网：前体纳米结构对地质聚合物结构和性能的影响

• 批准号: 1008102
• 负责人: Leslie Struble
• 金额: $ 20.92万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1008102&HistoricalAwards=false
• 关键词: Materials; World; Network; Effects; Precursor

This project is co-funded by the Office of International Science and Engineering (OISE), the Division of Civil, Mechanical and Manufacturing Innovation (CMMI) and the Division of Materials Research (DMR).NON-TECHNICAL DESCRIPTION: Geopolymers are attracting considerable attention in the engineering community as a potential replacement for portland cement in making concrete, which is commonly used to make structures such as buildings and highways. Geopolymers are formed by reaction between clay, which has first been heated to make it more reactive, and an aqueous alkaline solution. The main reason that geopolymers are attracting attention is that their use in concrete may reduce considerably the amount of greenhouse gases associated with concrete production. The purpose of this research project is to explore whether geopolymers can be made using fly ash instead of clay. Fly ash is a waste material produced during coal combustion, for example to generate electricity, and is often used as a replacement for some of the Portland cement in concrete. Some types of fly ash have been used successfully in production of geopolymer, but Class C fly ash, common in the middle and western US, have not. The key intellectual objective of this research is to understand how the chemical composition and molecular structure of the fly ash control behavior of the geopolymer. This research involves collaboration with Prof. Lauren Gómez-Zamorano of the Universidad Autónoma de Nuevo León (UANL) in Mexico. Prof. Gómez's work is supported through the Consejo Nacional de Ciencia y Tecnología (CONACYT). A broad objective is to demonstrate whether geopolymer is effective as a binding material in concrete. Public support of such projects is vital to the development and implementation of new construction material systems, and new systems are critical to the nation?s progress towards controlling greenhouse gas emissions without sacrificing construction of buildings and highways. Finally, civil engineering students are seeking knowledge about new materials for sustainable construction, and research experience in such systems will enhance our ability to provide that knowledge. TECHNICAL DETAILS: Geopolymer is the name given to synthetic aluminosilicate polymers formed by chemical reaction between a solid precursor, such as metakaolin, and an alkali solution. Geopolymers are attracting considerable attention as a replacement for Portland cement in concrete for civil engineering applications, in part because they much reduce the production of greenhouse gas associated with concrete. The chemistry of geopolymer formation is similar to the chemistry of zeolite synthesis, but the geopolymers are amorphous. Most of the research on synthesis of geopolymers has used metakaolin as the precursor. However, additional environmental benefits would be realized by producing geopolymers from waste materials, so this research is focused on synthesis of geopolymers using Class C fly ash as the precursor. Fly ash is a by-product of coal combustion, and Class C fly ash is derived from subbituminous and lignite coals, commonly found in the middle and western US. The key intellectual merit of this research is to understand how the chemical and molecular structures of the precursor control behavior of the geopolymer. To meet this objective, composition and structure of the precursor and the geopolymer are being studied using XRD, XRF, DSC, MAS-NMR, TEM, and SEM/EDX, and therefore graduate students in engineering are trained to use these fundamental characterization techniques. A related objective is to demonstrate whether geopolymer is effective as a binding material in concrete, and engineering behavior of concretes made using geopolymers is also of interest. This research has important impact on the cement and concrete industries; these industries are under considerable pressure to reduce greenhouse gas emissions and so they are looking at geopolymers as a possible strategy.

该项目由国际科学与工程办公室（OISE），土木，机械和制造创新部（CMMI）和材料研究部（DMR）共同资助。非技术描述：地质聚合物在制造混凝土时作为波特兰水泥的潜在替代品引起了工程界的极大关注，波特兰水泥通常用于制造建筑物和公路等结构。地质聚合物是通过粘土与碱性水溶液之间的反应形成的，粘土首先被加热以使其更具反应性。地质聚合物引起关注的主要原因是它们在混凝土中的使用可以大大减少与混凝土生产相关的温室气体的量。本研究项目的目的是探索是否可以用粉煤灰代替粘土制成地质聚合物。粉煤灰是在煤燃烧过程中产生的废料，例如用于发电，并且通常用作混凝土中某些波特兰水泥的替代物。一些类型的粉煤灰已成功地用于生产地质聚合物，但C类粉煤灰，常见于美国中西部，没有。本研究的关键智力目标是了解粉煤灰的化学组成和分子结构如何控制地质聚合物的行为。这项研究涉及与墨西哥努埃沃自治大学（UANL）的Lauren Gómez-Zamorano教授合作。Gómez教授的工作得到了国家科学技术委员会的支持。 一个广泛的目标是证明地质聚合物作为混凝土中的粘结材料是否有效。公众对这些项目的支持对于开发和实施新的建筑材料系统至关重要，而新系统对国家至关重要？在不牺牲建筑物和高速公路建设的情况下，中国在控制温室气体排放方面取得了进展。 最后，土木工程专业的学生正在寻求有关可持续建筑新材料的知识，在这些系统中的研究经验将提高我们提供这些知识的能力。技术规格：地质聚合物是指通过固体前体如偏高岭土与碱溶液之间的化学反应形成的合成铝硅酸盐聚合物。地质聚合物作为土木工程应用中混凝土中波特兰水泥的替代品吸引了相当大的关注，部分原因是它们大大减少了与混凝土相关的温室气体的产生。地质聚合物形成的化学过程类似于沸石合成的化学过程，但地质聚合物是无定形的。大多数合成地质聚合物的研究都是以偏高岭土为前驱体。然而，额外的环境效益将实现从废料生产地质聚合物，所以本研究的重点是合成地质聚合物使用C类粉煤灰作为前体。飞灰是煤燃烧的副产品，C类飞灰来自亚烟煤和褐煤，通常在美国中部和西部发现。这项研究的关键知识价值是了解前体的化学和分子结构如何控制地质聚合物的行为。为了实现这一目标，正在使用XRD，XRF，DSC，MAS-NMR，TEM和SEM/EDX研究前体和地质聚合物的组成和结构，因此工程专业的研究生接受了使用这些基本表征技术的培训。一个相关的目标是证明地质聚合物是否是有效的混凝土中的粘合材料，以及使用地质聚合物制成的混凝土的工程行为也是感兴趣的。这项研究对水泥和混凝土行业产生了重要影响;这些行业面临着减少温室气体排放的巨大压力，因此他们将地质聚合物视为一种可能的战略。