Experimental Testing of Retrofitted Corroded Reinforced Concrete Elements

Abstract

This thesis investigates the comparative mechanical behavior of conventional concrete and retrofitted reinforced concrete elements strengthened with repair mortars of class R4 and carbon fiber-reinforced polymer (FRP) systems. Corrosion remains a critical challenge to the durability and service life of reinforced concrete structures, making innovative strengthening and rehabilitation methods increasingly essential. The experimental methodology was developed following an extensive literature review on corrosion mechanisms, structural degradation, and state-of-the-art repair techniques employing FRPs and mortar-based systems. The study involved accelerated corrosion of prismatic concrete specimens, compressive and splitting tensile testing of cylindrical specimens, and flexural testing of repaired prisms across five categories: non corroded plain concrete, untreated reinforced concrete, corroded specimens and corroded specimens retrofitted using the above-mentioned materials. The combined use of high-performance mortars and carbon FRPs significantly enhanced the flexural capacity and ductility of corroded specimens. Results confirmed the efficiency of these composite systems in restoring load-bearing capacity and improving structural response under bending. Overall, the findings validate the applied retrofitting strategies as practical and effective solutions for the repair and retrofitting of corroded reinforced concrete elements. Their contribution to mechanical performance and durability highlights their wide applicability in infrastructure rehabilitation. Notably, FRP retrofitting demonstrated exceptional potential, restoring structural integrity and increasing flexural strength by up to three times compared to plain concrete.