A self-reinforced cementitious composite for building-scale 3D printing

A design scheme for self-reinforced cementitious composites to be used for building-scale 3D printing processes is introduced. The design is based on that of engineered cementitious composites, which include dispersed short polymer fibers to generate robust tensile strain-hardening. The mechanical property profile of these printable ECC materials is meant to eliminate the need for steel reinforcement in printed structures, providing more freedom and efficiency for building-scale 3D printing processes. The fresh state rheological properties have been systematically manipulated to allow printability. Effects on fresh state workability of several compositional ingredients and processing parameters are investigated herein. To maintain consistent printing performance with a batch mixing approach, thixotropy in the fresh state is exploited to temporarily decouple hardening behavior from the processing timeline. Minimal workability loss under continued shear agitation is achieved. Mechanical properties of the printable materials are characterized and the printability of the materials is demonstrated.