Interlayer adhesion strength of 3D-printed cement-based materials exposed to varying curing conditions

This study explores the influences of the curing regime on the interlayer adhesion properties of 3D printed cement (3DPC) paste. Phase compositions, pore structure, and microstructure of typical specimens were obtained by XRD, TG, MIP, SEM and BSE analyses. The results show that the bond strength of the 3DPC sample is decreased by air curing (AC) and stream curing (SC), compared with constant standard curing (CSC) specimens. In contrast, CO2 curing (CC) results in a good enhancement on the interlayer adhesion strength of the 3DPC matrix. The high plastic viscosity behaves as an improvement on the adhesion properties of the printed specimens with the similar level fluidity. Either air curing or stream curing degraded the adhesion strength of the printed mixture owing to the influence of hydration and form a looser microstructure with high porosity in the micro interface of printed pastes. The decreased bond strength of printed samples induced by relatively low humidity can be alleviated by carbonation curing. Therefore, the sequestration of carbon dioxide treatment provides a potential method for pursuing higher bond strength and lower environmental impact to manufacture 3DPC cement.