71 / 2022-04-12 16:50:27

Freeform embedded printing of vasculature in cementitious materials for healing-agent transport

Self-healing, Cement Paste, vascular network, Embedded 3D printing, Two-phase ink

Vascular systems for mass recycling promise to endow cementitious materials with self-recovering abilities, which would prolong their durability. However, the CM opacity and hypercritical requirements on brittle vessels lead to the lack of a feasible approach to freeform construct vasculature with three-dimensional connectivity. To address this, we have developed a strategy for in-situ vasculature construction that involves the embedded writing of fugitive inks within a supporting CM matrix (Schematic). The fugitive ink is a two-phase emulsion gel, which is versatile in terms of printability, free-discharging ability, and channel-sealing ability, enabling the formation of freeform, isolated vascular networks. To support the development of embedded printing strategy, we also analyzed the relationships between vessel features, CM hydration, writing speed, and flow rate. The tested aqueous healing agent moved through the printed vasculature to reach and heal cracks, demonstrating the effectiveness of this internal structure in terms of mass transport. We conclude that embedded printing allows the creation of vascular structures in cementitious materials and, ultimately, of intelligent construction materials.