Effect of layering molding process on strength of 3D printed composite cement based materials

Abstract

• Interlayer time gap and printing layers are key parameters influencing its strength. • When interlayer time close to initial setting time of 3DPC,strength loss reaches 36%. • Stress–strain curve of 3DPC has large fluctuation,showing stepped rise or decline. • The lowest strength of printed concrete is 60.4 MPa with 26.3 % loss. • The result of numerical simulation are lightly higher than the experiment. Compared with the traditionally casting concrete, one of the principal factors restricting the development of 3D printed composite cement based materials (3DPC) in building construction is the lower strength due to multilayer structure. In this study, by combining experiments and numerical simulations, the effects of interlayer time gap and printing layer numbers on the compressive strength were analyzed. The results show that the interlayer time gap is a key parameter influencing its strength. When the time is close to the concrete’s initial setting time, the loss of 3DPC strength reaches 36 %, and the optimum time should be between 5 and 15 min. The stress–strain curve of printing cement based materials has a large fluctuation, showing a stepped rise or decline, and the lowest strength is 60.4 MPa with 26.3 % loss. The results of numerical simulation are lightly higher than the experiment.