RETRACTED: Effect of different fibre types on the structural performance of recycled aggregate concrete beams with spliced bars

Abstract

Abstract Providing a sufficient lap length to spliced bars plays a vital role to provide an adequate flexural strength and flexibility to reinforced concrete (RC) beams. This study intends to assess the influence of polypropylene fibres (PPF) and steel fibres (SF) on the flexural behaviour of recycled aggregate reinforced concrete (RARC) beams with spliced bars. For this purpose, 40 specimens with a cross-section 150 mm wide and 200 mm high, and a length of 1500 mm with different lap lengths in spliced bars, were cast and tested. One specimen was selected as a control beam with no fibres, recycled aggregate (RA) and spliced bars. Then, RA was replaced at 100% mass replacement ratio. Furthermore, to increase the cohesiveness between bars and concrete, which affect the flexural behaviour of RC beams, SF and PPF were added at 0%, 1% and 2% (by volume) separately. Four-point bending tests were performed to measure the load-bearing capability, ultimate deformation, flexibility and stiffness of RARC beams with different lap lengths. The influence of the fibres and of the lap length on the structural performance of RARC beams was the main aim of this investigation. Experiments indicated that the lap-spliced bars length could be reduced by 40% when both RA and 2% fibres are used with no reduction of the flexural strength of the beams, and the influence of 2% SF is higher than that of PPF.