A study on the printability of manufactured sand concrete

Abstract

3D printed concrete (3DPC) is a rapid construction technology that uses concrete as an ink material to build three-dimensional structures layer by layer, with the advantages in free formwork, complex buildings printing and cost savings. In this paper, the printability and mechanical properties of 3D printed manufactured sand concrete (3DPMSC) were tested with different binder-to-sand ratios. The optimal dosage of manufactured sand was clarified, and the effect of manufactured sand dosage on pore characteristics was studied using CT scanning technology. The test results indicate that as the binder-to-sand ratio increases, the flowability, open time and extrudability of 3DPMSC gradually decrease. Improved buildability is obtained within the binder-to-sand ratio range of 1:1.1 ∼ 1:1.3. In addition, the compressive and flexural strengths of the 3DPMSC increase as the binder-to-sand ratio decreases, and the mechanical strengths are optimal in the Z direction. The pore distribution in 3DPMSC significantly varies in directionality, with an increase in both pore volume and number. This research lays a foundation on the engineering application and science exploration of 3DPMSC.