Mechanical and microstructural properties of 3D printable concrete in the context of the twin-pipe pumping strategy

To tackle the conflicts between the pumping and deposition process in 3D concrete printing, a twin-pipe pumping (TPP) system with a helical static mixer can be used. In this way, a cement-based mixture (without accelerator) and a limestone powder-based mixture (with a high dosage of accelerator) are transported separately and mixed within the helical static mixer just before extrusion. However, the helical static mixer will introduce striation...