Modelling the temperature gradient in 3D concrete printing

Three-dimensional concrete printing (3DCP) is a feasible substitution for conventional concrete, principally due to its capability to improve efficiency and diminish the ecological effect of the building industry. Notwithstanding its recognition, insufficient research has quantitively studied the temperature gradient during hydration in 3DCP. In this paper, a finite element model (FEM) is proposed to investigate the thermal performance of a 3Dprinted concrete. The model takes into account the heterogeneity in the generated heat of hydration depending on the time elapsed between layers. Thermal conduction between layers and thermal convection to the surrounding are also considered in the proposed model. The model was validated by experimental work. The effect of the printing technique on thermal properties is elaborated through a comparison with conventional cast concrete for a structural element with similar dimensions. Results show that the peak temperature and temperature difference in 3DCP is lower than in conventional casting by 8 degrees C and 15 degrees C respectively. Thus, the 3DCP is less susceptible to cracking due to thermal stresses.