3D-printed concrete shear keys: Design and experimental study

To incorporate 3D-printed concrete (3DPC) for modular construction of large-scale building and infrastructure, it is important to develop interlocks firmly connecting adjacent 3DPC modules and providing sufficient shear resistance to prevent inter-segment slippage. To develop guidelines for design and testing of 3DPC shear key interlocks, this paper proposes a fabrication method of such interlocks and studies various designs of 3DPC shear keys through push-off tests and slant shear tests for specimens with different shear key angles and shear joint inclinations. The experimental study focuses on the effect of these geometrical parameters on joint capacities and failure processes. The tests results showed that a smaller shear key angle slightly improved the shear capacity. The normalized shear stress of 3DPC shear keys was similar or slightly lower than precast concrete shear keys whereas shear capacity equations in the literature significantly underestimated the shear strength of 3DPC shear keys.