Effect of directionally distributed steel fiber on static and dynamic properties of 3D printed cementitious composite

•Mechanical properties of 3DPCC with compound effect of interfaces and steel fibers.•Unique behavior of 3DPCC subjected to projectile and explosive impacts.•Revised empirical formula for calculating the crater depth of 3D printed concrete. The reliability of 3D printed cementitious composite (3DPCC) is a major consideration for scientists. Steel fiber as a common method for reinforcement of cementitious composite was studied in this research for its effect on mechanical and dynamic properties. The distribution of steel fiber in 3DPCC was characterized by stereomicroscope and CT scanning method. Steel fibers were parallel to the print direction and distributed directionally in different degree at horizontal and vertical planes. The mechanical properties of 3DPCC was significantly influenced by directionally distributed steel fibers. Functional graded 3D printed cementitious composite (FGPCC) was prepared for coupled impacts including high velocity projectile impact and explosive impact. The crater depth and failure pattern of coupled impact were significantly changed by directionally distributed steel fibers. Modified empirical models were proposed for 3DPCC according to experimental results.