Modeling concrete deposition via 3D printing using reproducing kernel particle method

The quality and geometry conformity of 3D concrete printing are the two major concerns facing autonomous construction. To investigate the geometry of printed concrete and optimize the printing strategy, the reproducing kernel particle method (RKPM) was developed and implemented for the first time to describe the flow of fresh concrete and simulate the process of 3D printing. The proposed novel numerical simulation method is associated with a Bingham constitutive model, which was determined by a rotational rheometer. Physical slump tests were performed at various resting times to investigate the time-dependent behavior of concrete. An experimental parametric study of the geometry of a single-layer printed concrete was also conducted at various printing speeds and nozzle heights. Multi-layer printing cases were performed to investigate the cross-sectional deformation over the printed layers. The simulated values of slump over time compared well with the experimental measurements. As such, the proposed RKPM ability to capture time-dependent concrete behavior has been validated. The simulations based on the initially verified RKPM method can yield precise geometry predictions of a single- and multi-layer printed concrete, proving a wide range of application scenarios of the novel RKPM modeling approach.