Freeze-Thaw Performance of 3D Printed Concrete: Influence of Interfaces

Abstract

The long-term performance of 3D printed concrete structures is essential and among the various durability issues, frost damage is one of key importance, especially in cold locations such as Switzerland. For 3D printed materials, the presence of layer interfaces and cold joints is a potential issue in terms of frost resistance. Therefore, after extrusion, both cast and printed samples were prepared, and they were subjected to 300 cycles of freeze-thaw in accordance with ASTM C666. It was found that printed samples have lower resistance to freeze-thaw conditions compared to their cast counterparts. The lower resistance of the printed samples could be attributed to the heterogeneity in the microstructure, in particular to the higher capillary porosity in the interface region compared to that in the bulk. The higher capillary porosity could be confirmed based on the sorptivity test results.