The repair of recycled crushed brick aggregate RC beams with shear deficiencies with CFRP

Abstract

Repairing reinforced concrete (RC) beams using externally bonded carbon fibre reinforced polymer (CFRP) laminate has become one of the main rehabilitation techniques utilised to promote sustainability in construction. The aim of this study was thus to investigate the repair of rectangular simply supported reinforced crushed brick aggregate concrete beams with shear deficiencies in their design. The experimental work consisted of testing twelve full-scale beams (1400 x 200 x 150 mm) under two points load. The specimens were made of normal, and lightweight course aggregate concrete, four beam specimens were used as references, being tested until failure in shear to obtain the ultimate load carrying capacity, while the other specimens were loaded up to 60%-89.4% of the total load at failure, then repaired by wrapping in a layer of CFRP strips in two orientations (90°) and (45°). The variables investigated in this study were therefore the concrete type (normal and lightweight), shear span-to-effective depth ratio (a/d) with two variables (a/d=2.5) and (a/d=3), and the orientation of the CFRP. The results showed that a significant contribution was made by externally bonded CFRP in terms of repairing the beams, which not only refreshes initial shear capacity but also increases the ultimate capacity. The beams showed maximum reliability when the CFRP was oriented at 90° at a ratio of 72%.