Rheological requirements for printable concretes
Recently, scientists investigated the rheological requirements for printable concrete in terms of yield stress, viscosity, elastic modulus, critical strain, and structuration rate.
They first discussed the extrusion/deposition process at the level of the nozzle from a material perspective. They then focused on the rheological requirements needed to prevent the flow of one layer or the strength-based failure of the rising printed element. The scientists moreover discussed the rheological requirements needed to control the final geometrical dimensions of one layer and of the entire object, including buckling stability and surface cracking.
Effect of printing supports
They finally described the requirement for a proper intermixing of the layers interface and also noted that drying of the upper surface of the layer at rest could also play a major role on the interlayer bond. Finally, the scientists evaluated the effect of the use of printing supports (i.e. non-direct printing) on the above rheological requirements.
The study is published in: Cement and Concrete Research Volume 112, October 2018, Pages 76-85.
