Influence of cold joints on the behavior of reinforced concrete elements under flexion

Abstract

It is very difficult to fuse the entire structure monolithically without using cold joints, especially in the plane of intersection of the beam and slab concreting. In such cases, it is commonly employed to form the beam to the height of the slab and the rest of the beam is filled when the slab is cast. This technique allows the formation of a cold joint at the interface between new and existing concrete in the beam. This work evaluated the interference of the presence of concrete joints in the mechanical behavior of beams with and without cold joints. For the cold joint beam batch, one group was treated with structural mortar as a substrate bonding element to the new concrete. The displacement of the beams, when subjected to three point bending, with joint was compared with that of the reference beam, without cold joint. The results showed that the presence of joints does not significantly affect the mechanical behavior in the structural elements tested in the Limit of Service (ELS) and Ultimate Limit (ELU).