Torsion Behavior of Recycled Aggregates Concrete Beams With Openings

Abstract

Due to the fast rise in material and transportation costs, the recycling of construction waste has become a critical operation in the construction industry. Therefore, the use of construction waste as coarse aggregate should be researched to ensure that the structural behavior of these structures does not differ from that of non-recycled (natural) coarse aggregate buildings (NCA). An experimental investigation was conducted in this study to explore the influence of recycled coarse aggregate (RCA) on reinforced concrete beams with opening and subjected to pure torsion. Six beams with identical cross-sectional dimensions of 150 x 350 mm and a total span of 1400 mm attached monolithically at the two ends by two cantilevers having 200 mm wide and 350 mm long are included in the investigation. The tested beams included two solid beams and four beams with 300 x 150 mm opening. The existence of opening and the ratio of RCA replacement were considered as the parameters in this investigation. From the results of this study, the crack patterns of RCA and NCA specimens were similar, and the increase of RCA replacement ratio led to a decrease in the cracking and ultimate capacities. The existence of an opening changed the failure mode from sudden torsional shear failure as in the reference specimen without opening to crushing of concrete and concrete cover separation. A comparison between the experimental outcomes, the ACI code, and the ECP-203 code was conducted, and showed a good agreement with the experimental results.