Dissertation Defence: Nano-modified high-performance cementitious composites with recycled materials
June 8 at 9:00 am - 1:00 pm
Meraj Rubayat Kamal, supervised by Dr. Shahria Alam, will defend their dissertation titled “Nano-modified high-performance cementitious composites with recycled materials” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil Engineering.
An abstract for Meraj Rubayat Kamal’s dissertation is included below.
Examinations are open to all members of the campus community as well as the general public. Please email shahria.alam@ubc.ca to receive the Zoom link for this exam.
Abstract
Concrete is the most widely used man-made construction material, and its production consumes significant energy and non-renewable materials. The use of cement, the primary binding element of concrete, poses serious environmental threats, as cement production is the third-largest source of carbon dioxide emissions. The use of supplementary cementitious materials (SCMs) has proven effective in reducing cement demand, with coal fly ash (CFA) being the most widely adopted SCM. However, the global shutdown of coal-fired power plants has significantly reduced the availability of CFA, creating an urgent demand for alternative SCMs to support sustainable construction practices.
This research aims to utilize wood fly ash (WFA), a residue from wood biomass combustion, as an SCM to support greener construction applications. Although WFA demonstrates promising potential, its partially burnt state, particularly due to the presence of porous biochar, negatively impacts mechanical properties and freeze/thaw performance. To overcome these drawbacks, this study explores the valorization of WFA by adding a small dose of nano-silica (NS). In addition, recycled plastic fibres are introduced to improve tensile capacity, post-crack efficiency and shrinkage resistance, and their performance is systematically compared with that of conventional industrial steel fibres. A cradle-to-gate life-cycle analysis is further conducted to quantify the overall life-cycle performance of the nano-modified composites.
The results indicate that higher WFA replacement levels negatively affect performance; however, NS addition significantly mitigates these drawbacks. The addition of fibres improves the tensile strength and crack resistance. Overall, the combined use of NS and the recycled materials not only produces high-performance cementitious composites with improved mechanical and durability properties, but also reduces carbon emissions, thereby supporting low-carbon concrete construction.
