Bond performance between BFRP bars and 3D printed concrete

To improve the design and construction of three-dimensional (3D) printed concrete structures, the bond performance between basalt fibre reinforced polymer (BFRP) bars and 3D printed concrete were analysed via pull-out tests. It is found that the bond strength of 3D printed specimens was lower than that of mould-cast specimens, while the failure mode of BFRP bar-reinforced printed concrete was similar to that of reinforced common concrete. The bonding of sand-coated BFRP bars to 3D printed concrete was superior to that of smooth bars. The printing direction of concrete also affected bond performance, with the bond strengths of parallel and 45 degrees inclined specimens exceeding that of vertically printed specimens. By identifying defects at printed and bonding interfaces, the bond degradation mechanism was determined. Furthermore, a continuous bond-slip model was established to predict the bonding strength between BFRP bars and printed concrete, which agreed well with the experimental results. (C) 2020 Elsevier Ltd. All rights reserved.