Optimization study of process parameters for integrated 3D printing of concrete

Aiming at the problems of scattered process and large area of equipment for Concrete 3D printing with external pumping system, the research group designed an integrated 3D printing equipment. The printhead enables the mixing and blending of concrete powder with water and the extrusion of slurry. In this paper, we conducted experimental testing and research on integrated 3D printing process parameters, and the results showed that the print height (the height of the extrusion end of the printhead from the print cut surface) should be slightly higher than the material thickness. At the same time, the use of variable height can better realize the dimensional consistency and mechanical properties of the parts. In order to achieve the best mechanical properties, the screw speed should be 145 r/min in 3 days, the printing height should be stepped (the first and second layers are 15 mm, the third and fourth layers are 12 mm), the compressive strength is 23.98 ~ 24.30 MPa, the bending strength is 7.83 ~ 8.13 MPa. At 7 days, the screw speed should be 135 r/min, the print height is still stepped, the compressive strength is 31.89 MPa to 34.21 MPa, and the flexural strength is 8.99 MPa to 8.68 MPa.