Towards Additive Manufacturing: Pumping Flow Rate with Time-Dependent Material Rheology in 3D Cementitious Material Printing

3D printing has been getting increasing attention from both industry and academy in recent years. Unlike traditional construction processes, 3D cementitious material printing requires more accurate control on the pumping flow rate, which is known to be affected by the material rheology. In this paper, the effect of fresh rheology on the flow rate of cementitious material was studied experimentally in 3D cementitious material printing process. The material viscosity was measured via a large gap vane viscometer at different time points after mixing, and printing tests were conducted at the same time period to measure the flow rate based on volume conservation principle. Experiments showed that the flow rate was significantly affected by rheology change with respect to time. An open loop control method was then implemented to harmonize the flow volume per unit length during printing processes to improve printing quality.