Development and Characterization of Nano-Engineered Cement Based Composites for Sustainable Construction

胶凝材料在使用过程中的耐久性对其作为建筑材料的使用起着重要的作用。决定性能的参数与水泥基体系中的气孔网络、水化产物的稳定性以及各相之间的界面粘结密切相关。此外，生产各种各样的专用混凝土需要定制其新鲜和成熟的性能，包括流变性、渗透性和抗裂缝扩展能力。尽管外加剂和加固材料的发展，但尝试主要集中在性能的宏观工程上。鉴于水泥基系统的基础是纳米级的，纳米技术的出现现在需要协调一致地关注水泥系统的物理和化学性质，以适应每一种应用。然而，尽管在胶凝系统中利用纳米材料的一些努力已经存在，但它们在很大程度上仍然局限于仅将它们作为混合物加入。此外，这些尝试仅集中在机械改进上。申请人最近的工作突出了使用可调纳米材料来设计胶凝系统的物理和化学特性从而适当地定制其新鲜特性以及长期耐久性的巨大潜力。因此，这项提案将开发和表征纳米工程水泥基复合材料，以实现卓越的性能，特别是在加拿大的背景下。纤维素和其他纳米材料将首先被设计成在高pH环境中提供精确的特性，然后被引入水泥基系统。通过对新鲜和硬化特性的一系列检查，这项建议将开发和表征新一代可持续材料，并开发用于建筑的耐久混合料。

The durability during service of cementitious materials plays an important role in their operation as construction materials. The parameters that determine performance are related intimately to the air-void network, stability of hydration products and the interfacial bond between various phases in the cement-based system. In addition, the production of a wide variety of specialized concretes requires tailoring their fresh and mature properties including, the rheology, permeability and crack growth resistance. Notwithstanding the evolution of admixtures and reinforcing materials, attempts have largely focused at macro-engineering of properties. Given that the building block of cement-based systems is at the nanometric scale, the emergence of nanotechnology now warrants a concerted focus on tailoring the physical and chemical properties of the cementitious system to suit each application. However, while some efforts to utilize nanomaterials in cementitious systems exist, they remain largely restricted to merely incorporating them as admixtures. Further, these attempts have centred on mechanical enhancement only. Recent work by the applicants highlights a tremendous potential for the use of tunable nanomaterials to engineer the physical and chemical properties of cementitious systems and thereby suitably tailor their fresh properties as well as long-term durability. Therefore, this proposal will develop and characterize cement-based composites that are nano-engineered to achieve superior performance, specifically in the Canadian context. Cellulosic and other nanomaterials will be firstly designed to impart precise characteristics in a high pH environment and subsequently introduced into the cement-based system. Through a series of examination on fresh and hardened properties, this proposal will develop and characterize a new generation of sustainable materials and develop durable mixes for construction.