3D printing (3DP) technology is gaining interest in building and construction industry. However, the development of 3D concrete printing (3DCP) technique is not compatible with the conventional reinforcing strategies such as adding steel rebars. Therefore, fiber reinforced cementitious materials, especially strain hardening cementitious composites (SHCC) with strain hardening and multicracking behavior, are promising in 3D concrete printing.



However, the high volume fraction of fibers in SHCC makes the continuous pumping and extrusion process during 3D printing very challenging. Clogs during pumping and discontinuity during extrusion occur often. In this study, various materials parameters are probed to evaluate the pumpability and extrudability of SHCC. A SHCC mixture with high fiber dosage (2.0 vol%) are pumped and 3D printed continuously and smoothly. Direct tensile tests are conducted on the 3D printed filaments along the printing direction, after 28-day water curing. The tensile strength and ultimate strain are found to be significantly affected by the fiber dosage, etc.