Investigating Shrinkage and Mechanical Properties of 3D Printed Concretes Under Different Curing Conditions
摘要
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.