Open Collections

Orchy, Naila Nabila

University of British Columbia

With the increasing demand for durable infrastructure in chemically aggressive environments, the development of self-sensing cement-based materials has emerged as a promising approach for real-time SHM. Traditional methods of assessing infrastructure often rely on periodic inspections, which are not only costly and time-consuming but also limited in their ability to detect early-stage deterioration. This thesis investigates the development and application of carbon fiber-reinforced cement-based chemiresistors designed to detect chemical-induced degradation in concrete infrastructure. The research addresses a critical gap in Structural Health Monitoring, where traditional piezoresistive sensors primarily focus on strain detection, overlooking the effects of chemical exposure. The study explores the performance of these chemiresistors under exposure to 5% NaCl, 3% and 7% H₂SO₄, 10% and 20% NH₄NH₃, simulating conditions found in marine environments, wastewater systems, and agricultural settings. Cement composites incorporating two types of carbon fibers and hybrid fiber systems (carbon and steel fibers) were fabricated and subjected to cyclic wetting-drying exposure at 50ºC for 30 days to accelerate degradation and create a more realistic environment. Electrical resistivity and UPV were used to monitor degradation over time. The result of this research discusses the best type of carbon fiber, fiber content, and a range of FCR that is expected to be seen after 30 days of exposure. The research introduces cement-based chemiresistors as a novel SHM solution for detecting chemical damage in real time. The dual assessment of resistivity and UPV provided a comprehensive understanding of both electrical and mechanical degradation mechanisms. This enhances sensor performance. The findings have significant implications for developing smart, self-sensing materials capable of improving the durability and safety of critical infrastructure exposed to harsh chemical environments

Text

2025-04-25

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/90819

Civil Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/