3D printing lightweight aggregate concrete prepared with shell-packing-aggregate method - Printability, mechanical properties and pore structure

Abstract

It is a challenge to use porous lightweight aggregates to prepare 3D printing concrete as the water absorption process of porous lightweight aggregates has significant effect on its printability, especially when the content of lightweight aggregate is relatively high. In this paper, the effects of preparation methods on the rheological properties and printability of 3D printing lightweight aggregate (3DPLWC) are studied, aiming to prepare 3DPLWC with high lightweight aggregate content. 3DPLWC with 50, 75 and 100 vol.-% substitution of fine river sand with clay ceramsite sand (CCS) are successfully prepared with shell-packing-aggregate method. The mechanical properties and pore structure of 3DPLWC with different CCS contents are then studied. It is found that the printing process has caused the anisotropy of 3DPLWC, and the specific strength of 3DPLWC is lower than cast counterparts. For 3DPLWC, the increase of pre-wetted CCS content contributes to the decrease of matrix porosity and the increase of circularities of matrix pores in the printed specimens. The results of this study can provide guidance for the preparation of 3DPLWC with different density levels.