Use of crystalline waterproofing technology and SCMs to develop sustainable and smart self-sealing materials

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Canadian infrastructure is in need of cementitious materials that are both durable and sustainable for use in new and repair applications. This project will focus on development of innovative cement-based materials that utilize industrial wastes like slag and are also combined with admixtures that are based on crystalline water proofing technology. These admixtures based on crystalline technology remain passive until moisture enters the pores of concrete and then react with this moisture forming pore blocking crystals making the material less permeable. This characteristic can be utilized to develop smart materials that can seal with time thus referred to as "self-sealing." The reduction in both permeability and "self-sealing" leads to improved durability of the material in turn extending the life of structures where this material is utilized. Crystalline based admixtures such as KIM (produced by Kryton International Inc.) have been used for decades and its effectiveness in reducing permeability is well understood. However, the interaction of this admixture when combined with high volume of slag and Portland Limestone Cement that was recently introduced in the Canadian markets is not known. In this project, a test matrix consisting of eight mixes with variables such as slag content, addition of KIM, and use of PLC will be considered. The change in the microstructure of the cement phase of the various mixes will be studied using Scanning Electron Microscope and world's highest magnification Scanning Transmission Electron Holography Microscope at the University of Victoria. The next milestone will involve characterizing the restrained plastic and drying shrinkage cracking potential of the various mixes. The self-sealing characteristics of the various mixes will be quantified using an innovative technique co-invented by the applicant and the industry partner. The final phase of this project will involve measuring the chloride ion concentrations in concrete after long-term simulated exposure. The findings of this project will be beneficial to the Canadian construction industry and will also allow the industry partner to further their understanding about KIM admixture and lead to development of smart self-sealing materials.