Experimental Study on the Flexural Strengthening Effect of Recycled Coarse Aggregate RC Beams Strengthened with Carbon Fiber Reinforced Polymers

탄소섬유보강재로 보강한 순환골재 콘크리트보의 휨보강효과에 관한 실험적 연구

Recycled coarse aggregates (RCAs) made by construction waste can be used as concrete aggregates. Nevertheless, some studies have indicated that increasing the RCA replacement ratios of the reinforced concrete (RC) structures resulted in a decrease in failure load capacity, in strength degradation, and in severe cracking. In this study, the use of carbon fiber reinforcement polymer (CFRP) sheets and CFRP plates in RC structures was evaluated for their effect in suppressing cracking and in adding strength to the structure. Twelve specimens including five control beams were fabricated, using various recycled coarse aggregate substitution rates, to compare and analyze the CFRP material's reinforcement effects. All specimens were fabricated with stirrups as simple beams with fixed span to effective depth ratio of 3.88 to 1 (i.e., a/d=3.88). The main variables studied in this investigation are (1) replacement level of recycled coarse aggregates (0, 15, 30 and 50%), (2) tensile reinforcement ratio (0.8, 1.27%), and (3) the incorporation of CFRP sheets and/or CFRP plates.