FLEXURAL BEHAVIOR OF REINFORCED CONCRETE BEAMS RETROFITTED WITH ULTRA HIGH PERFORMANCE CONCRETE USING LOCAL MATERIALS

Abstract

The performance of reinforced concrete (RC) elements often declines over time due to material deterioration, environmental exposure, or changing functional requirements, leading to reduced safety and serviceability. This study investigates the flexural behavior of RC beams retrofitted with Ultra-High-Performance Concrete (UHPC) overlays developed entirely from locally available Indonesian materials, without the use of nanomaterials, making it more practical and sustainable for developing regions. RC beams with a compressive strength of 30 MPa were retrofitted with UHPC layers of 15, 30, 50, and 70 mm thickness, while a 50 mm normal concrete layer served as a control. Experimental testing included load–deflection monitoring, stress–strain measurement, crack pattern observation, and failure mode assessment. Findings revealed that a 30 mm UHPC overlay achieved the highest load-carrying capacity, while 50 mm provided an optimal balance of stiffness, ductility, and toughness. In contrast, 70 mm caused over-reinforcement and brittle failure, and 15 mm offered minimal enhancement. These results demonstrate that UHPC produced from local resources offers an effective, durable, and sustainable retrofitting approach for RC beams in resource-limited settings.