Design of 3D printable concrete based on the relationship between flowability of cement paste and optimum aggregate content

This paper deals with the mixture design of 3D printable concrete (3DPC) based on the theoretical analysis of the yield stress of mortar. It has been found that there is a linear relationship between the flowability of paste and optimum aggregate content in 3DPC mixes which comply well with printability requirements. Additionally, the linear relationship obtained from the 3DPC with coarser natural sand can be also applied to the 3DPC with finer sand in accordance with the excess slurry theory. It is revealed that if the excess slurry thickness and the mix proportion of paste are the same, the mortar has similar rheological behavior. The verification experiment confirms that combined with the linear relationship between the flowability of cement paste and optimum aggregate content, the flowability of paste is a useful parameter for the mixture proportion design of 3DPC.