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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749369
• 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。本研究计划旨在利用纳米技术方法开发一种新型的煅烧粘土基胶凝粘合剂。首先，我们将更深入地了解含有煅烧粘土的水泥浆在早期和长期以及暴露于潜在的恶劣环境条件下的纳米结构。然后将使用播种方法来修改钙铝硅酸盐水合物（C-A-S-H）的纳米结构，这是混凝土中含有煅烧粘土的主要结合相。播种方法能够控制C-A-S-H相的化学计量和结构组成，从而允许针对各种应用对水泥体系进行纳米结构定制。我们将研究三种煅烧粘土。它们包括高纯度和水泥级偏高岭土以及煅烧的油砂细尾矿。尾矿管理是阿尔伯塔省油砂开采部门面临的一个重要环境挑战。该方案将为尾矿管理提供切实可行的解决方案。拟议的计划将对促进新型和可持续的结合煅烧粘土粘合剂在建筑工业中的应用产生重大影响。可推广应用于粉煤灰、矿渣等其他工业副产品。此外，它将为修改现行标准奠定基础，以包括长期大批量煅烧粘土基水泥生产的规范。一个多元化的高素质人才群体将被培训成为加拿大和世界范围内设计和实施可持续基础设施材料的领导者。