Simulation on pull-out performance of steel bar from 3D-printed concrete

In this study, a finite element (FE) model for the pull-out test was established and verified to examine the influence of printed concrete-to-concrete interfaces on the pull-out performance of steel bar from 3D-printed concrete. The stress transfer, debonding process, and failure mechanism of 3D-printed specimen were revealed by detailed interfacial stress analysis. Moreover, the effects of the interfacial bond strength, filament size, angle between the steel bar and the printing direction (alpha), and bond length on the pull-out performance were intensively investigated. The numerical results showed that the failure pattern changed from the conventional pull-out failure to interfacial bond failure induced by 3D-printed concrete-to-concrete interfaces. Compared with the pullout specimen with alpha = 0 degrees, the peak load of pull-out specimen with alpha = 90 degrees increases by 9.6%, which became the weakest when angle alpha = 30 degrees. Moreover, the failure mode was observed to be influenced by the relative strength of the interlayer and interstrip interfaces and their distributions.