Epoxy Grout Composites: Incorporating Construction Waste for Enhanced Under-Grouting

Abstract This study explores the potential for utilizing construction waste as a filler material for synthesizing epoxy grout composite for use in under-grouting applications. Three types of epoxy grouts were produced, with identical resin and hardener compositions but with 2%, 5%, and 10% proportions of silica sand fillers replaced with construction waste obtained from building demolition sites in the form of crushed rocks. The synthesized epoxy grout samples were characterized and evaluated after being left to cure for 7 and 28 days. A standard epoxy grout with no added construction waste served as a control for comparing the performance of the modified epoxy grout composites containing construction waste. The microstructure and mechanical properties of the synthesized epoxy grout samples are thoroughly analyzed. The results showed that the grout with 10% construction waste exhibited a compressive strength of 117.5 MPa and a compressive modulus of elasticity of 13.88 GPa, indicating a 10.84% and 12.02% improvement over the benchmark grout sample. Among the grout composites, those with 2% construction waste demonstrated the highest flexural properties, achieving a strength of 35.38 MPa. Examination through scanning electron microscopy reveals that, in epoxy grout composites with construction waste, silica sand clusters are substituted by particles of construction waste, resulting in enhanced compressive strength and modulus of elasticity values. Optical microscopy analysis shows that adding construction waste material to epoxy-based grout composite increases the effective composite compressive strength by reducing void fraction and enhancing mechanical interlocking between the filler and epoxy matrix. The current results emphasize the feasibility of utilizing construction waste-modified grouting material on a large industrial scale, highlighting its sustainability and cost-efficiency advantages.