Rehabilitation of reinforced concrete beam: Sustainable restoration mortar with waste materials

Abstract

The current application of epoxy resin in the installation of fiber sheets for concrete beam restoration presents practical challenges, limited fire resistance, and lacks environmental sustainability. Additionally, epoxy resin cannot be used on wet surfaces as it compromises adhesion and reduces durability. In this study, we propose an effective mortar formulation that incorporates waste materials such as marble powder (MP), red mud (RM), and electric arc furnace dust (EAFD) for fiber sheet installation. The performance of the developed mortar was comprehensively assessed through various experiments, evaluating compressive and tensile strengths, water absorption (WA), sulfuric acid resistance (SAR), and microstructural characteristics of the restoration mortars. Furthermore, three reinforced concrete (RC) beams were constructed and subjected to a four-point bending test. One beam was strengthened with carbon fiber-reinforced polymer (CFRP), while the other two utilized fiber-reinforced cementitious material (FRCM) with either CFRP mesh or glass fiber-reinforced polymer (GFRP) bar. The findings reveal that RC beams strengthened with CFRP mesh-restoration mortar and GFRP rebar-restoration mortar exhibit load-carrying capacities 13% and 36% higher, respectively, compared to that reinforced with CFRP sheets. This study lays the foundation for future research by demonstrating, for the first time, the superior performance of mortar-based restoration over epoxy resin, thereby opening up new possibilities for the development of concrete element restoration.