Transport properties of 3D printed cementitious materials with prolonged time gap between successive layers

Abstract

3D concrete printing is a promising additive manufacturing technique, integrated in construction industry to improve the geometrical complexity without expensive formworks. Due to the layered extrusion of the material, the porosity increases. This makes the component more prone to shrinkage and crack formation and increases the preferential ingress paths for aggressive substances. This can affect the durability and microstructure of the printed elements in a negative way. To assess the durability of 3D printed materials, three deterioration mechanisms (i.e. chloride ingress, carbonation and freeze/thaw) are investigated, considering different time gaps (i.e. 0 and 30 min) in between the layers and a comparison with traditional cast specimens was made. It was found that the resistance of 3D printed specimens against the penetration of chemical substances decreases with an increasing time gap. Compared with cast specimens, a higher saturated mass after frost attack could be observed in case of printed specimens.