Basic Experimental Evaluation of Fresh and Hardened Properties of Mortar Using Additive Manufacturing

Abstract

Recently, the three-dimensional concrete printing (3DCP) method has been garnering considerable interest owing to its ability to significantly reduce the construction time. In this study, 3D printing or additive manufacturing was applied to mortar using a small gantry type equipment and the performance of the method was evaluated. The mixture proportioning for good mortar printing and deposition was derived. The parameters of printability, buildability, compressive strength, flexural tensile strength, and anti-washout were considered for the performance evaluation. The results showed good printability with a constant width and no surface defects. In the buildability test, the rate of yield stress development increased, and the rate of change in the layer height decreased as the interlayer time interval increased during underwater printing. The flexural tensile strength of the specimen cast into the mold was lower than that of the specimen extracted from the additive parts owing to the longitudinal confinement during printing. The compressive strength in the lateral direction was slightly higher than that in the perpendicular direction, whereas the compressive strength of the specimen extracted from the part printed underwater was higher than that of the specimen cast into the mold.