Programmable toughening for 3D printed concrete and architected cementitious materials

Cementitious materials have been long suffered from toughness issue. Recent advances in 3D printing techniques enable innovative material shaping and customized functionalization. Herein, we propose a novel strategy for achieving multiscale and programmable toughening for cementitious composites by integrating the “wet spinning” industrial manufacturing process of polymer fibers/films into 3D printing procedure. In this strategy, the dehydration-induced polymer precipitation and the hydration of cement are synchronized, while the internal stress generated during the printing process drives the polymers to form desired toughening structure. Within this concept, anisotropic and programmable toughening are achieved by adjusting the printing parameters to control the polymer structure. This strategy is highly compatible with architected material design under high toughening component and extremely small voxel scale. Through this, we achieved an 80 % increase in flexural strength and a 102 % increase in fractured energy for the 3D printed cementitious bouligand structure at centimeter-level for the first time.