The Effect of Layer Cross-Section on Plastic Shrinkage Cracking of 3D-Printed Concrete Elements

There is great potential for 3D concrete printing to revolutionize the construction industry in the near future. A major aspect of this technology transfer to the practical application will be the ability to control and mitigate the shrinkage of printed elements and shrinkage-related cracking. In the first hours after extrusion, 3D-printed concrete elements are subjected to the accelerated evaporation of the water. This leads to the development of high negative capillary pressure in the system. Before solidification, primary negative capillary pressure is responsible for the volumetric contractions of the 3D-printed concrete elements and subsequently cracking. Over time, printed structures with cracks degrade their durability, functionality, and aesthetics. Mitigating plastic shrinkage and shrinkage cracking is essential for 3D-printing sustainable and durable structures. The article analyses the cracking of the 3D-printed elements having different cross-sections of the layers. It was found that concrete elements printed with thin filaments are more susceptible to plastic shrinkage cracking than those printed with thicker filaments.