Enhancement of 3D printed cementitious composite by short fibers: A review

Recently, the construction industry has been striving to develop faster production processes with the ever-increasing complexity of forms. In order to achieve enhanced productivity and intricate forms, architects and engineers have moved steadily toward a digitally-driven manufacturing process. Geometric freedom, waste reduction, lower construction costs and greater speed make a 3D-printed cementitious composite (3DPCC) a highly attractive alternative for future construction. A major challenge to expanding this technology is the limited range of printable concrete materials and complications in laying conventional reinforcement. Several studies have shown that short-fiber reinforcement can enhance the toughness of cement-based 3D printed materials, although short-fiber reinforcement normally offers random distribution and an unknown direction of reinforcement. This paper reviews state-of-the-art research utilizing the short fibers in digital concrete construction based on four aspects: fresh behavior, printability and buildability, interlayer adhesion, and anisotropy behavior of the 3DPCC with fibers. The influence of different kinds of short fibers on 3DPCC properties is discussed. This review provides critical information to understand each type of fiber on the 3DPCC and to select the most suitable fiber for the specific application of 3DPCC.