Investigating Shrinkage and Mechanical Properties of 3D Printed Concretes Under Different Curing Conditions (2025-03)¶

Controlling the shrinkage of 3D printed concrete (3DPC) has always been challenging. The absence of molds and early exposure to environmental conditions establish a foundation for increased shrinkage. This study examines the effects of various curing methods on shrinkage, mass loss, and the compressive and flexural strength of 3DPC. Also, the impact of short-term curing is considered. The results reveal that water curing, due to its provision of supplementary water for the complete hydration of cement, delivers the most favorable outcomes; however, it is not a practical approach for 3DPC applications. For example, the flexural strength of samples cured in water for 7 days (5.72 MPa) exceeds that of samples cured by alternative methods over 28 days (5.33–5.58 MPa). Conversely, the most practical curing method uses a curing agent, which positively impacts shrinkage reduction and strength improvement. The compressive and flexural strengths of samples cured with this method were 7.8% and 8.1% higher, respectively, than those of unprotected samples at 3 days. The synergistic effect of combining these curing methods with one day of wet curing is also evident in the improved results. A single day of wet curing reduces the mass loss by 2.2% and 0.5% in SA and SS samples, respectively.