Stress-strain state of RC beams after restoration of the compressed concrete zone

Abstract The article presents the results of a study on the stress-strain state (SSS) of reinforced concrete beams after the restoration of the compressed concrete zone damaged due to physical loading. The experimental samples included beams with reinforcement turned down to a diameter of 20 mm to simulate corrosion processes, with and without subsequent restoration of the compressed concrete zone. To restore the damaged compressed concrete zone, a high-strength repair mortar, Sika MonoTop-4012, was used, significantly improving the mechanical properties of the structures. The results confirm the effectiveness of the applied mortar, achieving a 22% increase in the load-bearing capacity of the beams beyond the yield limit of the reinforcement compared to undamaged samples. A reduction in deflections was observed, indicating increased structural stiffness. The application of digital image correlation (DIC), integrated with computerized sub-micron indicators, enabled the acquisition of a detailed stress distribution and localized deformations with reduced measurement errors compared to traditional methods. This approach ensured precise monitoring of SSS changes under loading conditions and validated the effectiveness of the restoration efforts. The obtained data demonstrate the feasibility of using high-strength repair mortars in combination with modern monitoring techniques for restoring reinforced concrete structures. Future research may focus on assessing the long-term durability of restored beams under real operational conditions.