Experimental and numerical study on flexural behaviour of geogrid-reinforced beams

The deterioration of non-structural concrete elements in harsh environments presents a significant concern, particularly in Canada’s cold regions. Conventional steel reinforcements are prone to corrosion, and anticipated climate changes, such as increased temperature fluctuations and freeze-thaw cycles, demand more durable alternatives to prevent premature cracking. This study investigates the use of low-ductility fibreglass geogrids and high-ductility polymeric geogrids to enhance the flexural performance of plain concrete beams. Twenty-one beams (550 mm × 150 mm × 150 mm) with varying reinforcement configurations were tested under four-point bending to assess load-deflection behaviour, mode-I fracture energy, and failure modes. Results showed that fibreglass geogrid reinforcement improved flexural stiffness by 40%, fracture energy by 11%–34%, and displacement capacity by 15%–45%, outperforming polymeric geogrids, which only enhanced deformation by 10%. Additionally, finite element models validated against experimental data were developed to examine the influence of temperature on fibreglass-reinforced beams. The models incorporated temperature-dependent material properties and evaluated midspan deflection and ultimate load under varying conditions. Findings revealed improved performance with decreasing temperatures (down to −30°C), with consistent cracking strength observed from 23°C to 60°C. This research highlights the promise of fibreglass geogrid reinforcement as a viable strategy for enhancing concrete durability in cold climate regions.