Development of Nanostructured Cementitious Binders Incorporating Calcined Clays

掺有煅烧粘土的纳米结构水泥基粘结剂的开发

• 批准号: RGPIN-2018-04755
• 负责人: Khoshnazar, Rahil
• 金额: $ 2.26万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=713202
• 关键词: Development; Nanostructured; Cementitious; Binders; Incorporating

Construction of concrete infrastructure relies primarily on the application of Portland cement and its hydrated phases as a binding material. This requires the annual production of about 4,000 million tonnes of cement worldwide which accounts for 5-8% of global CO2 emissions. Improvements in cement technology and development of new cementitious binders are, therefore, necessary to reduce the emissions. Calcined clays are among the most promising sources of supplementary cementitious materials which can be used as partial substitutions for Portland cement. Their application, in addition to the environmental advantages, can benefit the concrete performance. Metakaolin, the most reactive calcined clay, is currently used in projects where high strength and improved durability are required. Typical replacement levels of metakaolin are currently about 10-20% by mass of Portland cement. Innovative approaches to promote wider applications of metakaolin, and permit higher replacement levels can significantly reduce the emissions. In addition, the use of locally available and less expensive calcined clays is needed. This research program is aimed at developing a new class of calcined clay-based cementitious binders using a nanotechnology approach. A more in-depth understanding of the nanostructure of cement pastes incorporating calcined clays at the early ages and long-term as well as in exposure to potentially aggressive environmental conditions will first be provided. A seeding method will then be used to modify the nanostructure of calcium-alumino-silicate-hydrates (C-A-S-H), the principal binding phases in concrete incorporating calcined clays. The seeding method enables control of the stoichiometry and structural composition of the C-A-S-H phases permitting nanostructural tailoring of cement systems for various applications. Three types of calcined clays will be studied. They include a high purity and a cement grade metakaolin as well as calcined oil sands fine tailings. Management of tailings is an important environmental challenge for the oil sands mining sector in the Province of Alberta. This program will provide a practical solution for the tailing management. The proposed program will have a significant impact on promoting the application of novel and sustainable binders incorporating calcined clays in the construction industry. It can be extended for the use of other industrial by-products such as fly ash and slag. In addition, it will develop the basis for modifying the current standards to include specifications for production of high-volume calcined clay-based cements in the long-term. A diverse group of highly qualified personnel will be trained to become leaders in designing and implementing sustainable infrastructure materials in Canada and worldwide.

混凝土基础设施的建设主要依赖于波特兰水泥及其水化相作为粘结材料的应用。这需要全球每年生产约40亿吨水泥，占全球二氧化碳排放量的5-8%。因此，水泥技术的改进和新型胶凝粘合剂的开发对于减少排放是必要的。煅烧粘土是最有前途的补充胶凝材料之一，可以部分替代硅酸盐水泥。它们的应用，除了具有环境优势外，还可以使混凝土性能受益。偏高岭土是最具活性的煅烧粘土，目前用于要求高强度和提高耐久性的项目。偏高岭土的典型替代水平目前约为波特兰水泥质量的10-20%。创新方法促进偏高岭土的更广泛应用，并允许更高的替代水平，可以显著减少排放。此外，还需要使用当地可获得的较便宜的煅烧粘土。