Controlling Three-Dimensional-Printable Concrete with Vibration

This study proposes using vibration to facilitate three-dimensional (3D) printing of concrete with coarse aggregate, which could lower material costs and decrease shrinkage compared with current 3D-printed cementitious structures. 3D printing of concrete requires concrete to behave like a fluid during pumping and extrusion but like a solid after extrusion. This difference in behavior could potentially be accommodated by using vibration to control the yield stress of concrete. The objective of this study was to understand the effect of vibration on the concrete yield stress and its implications for 3D printing. In this study, a concrete rheometer was modified to measure the yield stress of concrete during vibration. The results of the study show how the effect of vibration on the yield stress of concrete is dependent on the aggregate volume fraction and the packing of the aggregates. It was also observed that the effect is instantaneous and reversible.