Steel bar - concrete bond behaviour in the context of the ETS shear strengthening technique for RC beams

Abstract

The use of near-surface mounted (NSM) technique has been proved to be very effective to increase the flexural and shear resistance of reinforced concrete (RC) beams. However, the NSM is not applicable for the shear strengthening of RC slab, thus a new technique was developed (ETS – Embedded Through-Section), consisting in opening holes across the slab thickness in the shear zone, where bars are inserted and bonded to concrete by an adhesive material. To assess the contribution of the bond mechanism for the shear strengthening effectiveness of this technique, a comprehensive pullout test program was carried out, where the influences of the type of adhesive, a thickness of the adhesive layer, diameter of the strengthening bar and bond length on the bond phenomena were assessed. The experimental program is described and the obtained results are presented and analysed in this paper.