Investigation of Flexural and Compressive Strengthening of Aging RC Beams and Columns Using Carbon Fiber Reinforced Polymer (CFRP)
Keywords:
Carbon Fiber Reinforced Polymer (CFRP), Reinforced Concrete (RC), Structural Strengthening, Flexural Strength, Compressive Strength, Retrofitting, Aging Structures, Rehabilitation, CFRP Wrapping, RC Beams, RC Columns, Composite Materials, Structural Performance, Sustainable InfrastructureAbstract
The deterioration of aging reinforced concrete (RC) structures due to environmental exposure, corrosion of reinforcement, fatigue loading, and increasing service demands has become a major concern in the field of civil engineering. The reduction in load-carrying capacity, excessive cracking, and stiffness degradation often necessitate effective strengthening and rehabilitation techniques to ensure structural safety and serviceability. Among the available retrofitting methods, Carbon Fiber Reinforced Polymer (CFRP) has emerged as a highly efficient strengthening material because of its high tensile strength, lightweight nature, corrosion resistance, and ease of installation.
The present study investigates the effectiveness of CFRP in enhancing the flexural and compressive performance of aging RC beams and columns. An experimental program was conducted using M30 grade concrete specimens comprising control and CFRP-strengthened beams and columns. Aging conditions were simulated through preloading and controlled cracking prior to strengthening. CFRP sheets were externally bonded to the tension face of RC beams to improve flexural behavior, while RC columns were fully wrapped with CFRP sheets to enhance confinement and compressive strength. Standard laboratory tests, including slump cone tests, compressive strength tests, and flexural strength tests, were performed to evaluate the structural response of the specimens.
The experimental results demonstrated significant improvements in both compressive and flexural capacities after CFRP strengthening. The average compressive strength increased from 31.51 MPa for control specimens to 42.81 MPa for CFRP-strengthened specimens, representing an enhancement of approximately 35.86%. Similarly, the average flexural strength increased from 4.60 MPa to 6.75 MPa, corresponding to an improvement of approximately 46.74%. CFRP-strengthened specimens also exhibited reduced crack propagation, lower deflection, improved stiffness, enhanced ductility, and greater load-carrying capacity compared with conventional RC members.
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