Salt Scaling Resistance of 3D Printed Concrete

Extrusion-based 3D concrete printing is an emerging technology in the construction field due to the many advantages associated with it as compared to conventional mould casting technology. However, many aspects like durability and long-term service performance are yet to be investigated in detail. The present study focuses on understanding the salt scaling resistance of 3D printed concrete samples. 3D printed concrete samples were prepared with a Portland cement mixture on the one hand and a mixture containing a blend of Portland cement and blast furnace slag on the other hand. The printed samples were subjected to freeze and thaw cycles with a 3% saltwater concentration. It was observed that the 3D printed samples exhibited better resistance against salt scaling compared to the mould cast samples made with the same mixture. The pore structure of the 3D printed samples was characterized by mercury intrusion porosimetry. It was observed that the presence of a higher amount of interconnected and coarser pores at the interlayer region of the 3D printed samples, acting like pockets of air voids, facilitates the release of ice crystallization pressure during the freezing phase. The study gives insights into the durability characteristics and feasibility of using 3D printed concrete elements exposed to aggressive environmental conditions.