Feasibility of Retrofitting Reinforced Concrete (RC) Column Using Ultra-High-Performance Concrete (UHPC): Experimental Investigation

Abstract Utilizing ultra-high performance concrete (UHPC) for strengthening reinforced concrete (RC) columns has emerged as a compelling approach, particularly for retrofitting. Unlike traditional normal strength concrete jacketing methods, UHPC offers a more efficient alternative. These methods often require substantial increases in column size to achieve desired enhancements in axial, shear, and flexural capacities. By quantitatively assessing the volume of material utilized against the resulting benefits in ultimate capacity and service life extension, it becomes evident that UHPC holds significant promise in retrofit and upgrading endeavors. In the present study, a total of four columns were experimentally tested, including one control column in need of retrofitting and three retrofitted columns, one with a fully reinforced normal strength concrete jacket and the other two with fully reinforced UHPC jackets. The experimental results reveal that the UHPC jacket increases the stiffness, strength, and energy absorption of the columns compared to the normal strength concrete jacket. This study evaluates the feasibility and performance of RC columns strengthened using UHPC. It examines hysteresis curves, failure modes, stiffness degradation, and sectional curvature to assess the efficacy of the strengthening and retrofitting methods.