Enhancing mechanical properties of concrete with 3D printed vascular networks via carbonation strengthening

Vascular systems offer promising potential for enabling self-recovery in cementitious materials, but their construction in three dimensions presents significant challenges. Our group has developed an embedded printing strategy allowing for the freeform construction of 3D hollow vascular channels, overcoming previous limitations. However, concerns persist regarding the weakening of mechanical properties caused by these vascular channels. In this study, we utilize carbon dioxide curing to reinforce the vascular wall, mitigating the mechanical loss associated with hollow vascular channel. We investigate the effect of carbonation on the vascular channel wall's morphology, composition, and microhardness along the radial direction to gain insight into its impact. Additionally, we analyze the influence of both vascular channels and carbonated vascular channels on intensity and cracking behaviors under various loading directions. The findings from this investigation provide essential insights for the design and optimization of vascular networks in concrete structures.