Shear Behavior of Reinforced Recycled Aggregate Concrete Beams: Fid-Bau Portal

Shear Behavior of Reinforced Recycled Aggregate Concrete Beams

Wardeh, George / Ghorbel, Elhem / Gomart, Hector / Fiorio, Bruno / Pliya, Prosper

Abstract The results from an experimental study on the shear behavior of concrete made with natural aggregates (NAC) and 100% recycled aggregates (RAC) are presented in this study. Full scale 200 × 250 × 1900 mm reinforced concrete beams without stirrups were manufactured from two mixtures with C35/45 target class of compressive strength and S4 class of workability. The beams were tested under 4 points bending for a shear span-to-depth ratio (a/d) equal to 1.5 and 3.0. The mechanical properties of two mixtures were characterized in terms of compressive strength, splitting tensile strength, and modulus of elasticity. The experimental results show that, for the same class of compressive strength, the shear failure mechanisms in recycled aggregate concretes are the same compared to the natural aggregate concretes while the shear strength is lower. The decrease in the shear strength is consistent with the decrease in the splitting tensile strength of the RAC mixtures compared to the NAC mixtures. In terms of load–deflection response, RAC beams showed flatter slopes compared to the NAC beams. Fracture surfaces of beams with a/d = 3.0 were observed by using an optical microscope for both NAC and RAC. It was found that the failure of NAC beams is done mainly by the detachment of natural aggregates whereas it occurs by the rupture of recycled ones with a denser cracking network in the case of RAC beams. The experimental shear strengths were compared with the shear provisions of design standards. It is found that the design equations remain applicable to reinforced recycled aggregate concretes.