Tensile Performance of Interlayer Interface of Interlocking 3D Printed Concrete with Single Toothlike Nozzle (2025-03)¶

Interlocking 3D printed concrete printed by tooth-like nozzles exhibits superior interfacial tensile performance. However, the influences of geometric parameters on the interlayer tensile strength of interlocking specimens remains unclear, and there is an urgent need to establish formulas to quantify the influences. To address these issues, this study, based on a novel single-tooth nozzle designed to enhance interlayer performance, comprehensively considers macro-mechanical performance testing and micro-porosity analysis. It reveals the failure modes of interlayer interfacial tension in single-tooth interlocking 3D printed concrete and proposes the tensile strength calculation formulas. Firstly, the theoretical analysis of the interlayer interfacial tensile strength of 3D printed concrete was performed. Then, conducted uniaxial tensile tests and validation experiments, and confirmed the validity of the theoretical formulas. Finally, the stress-strain curves of interlayer interlocking specimens with different single-tooth angles were analyzed. The results indicate that: (1) The interlayer interfacial tensile strength of interlocking 3D printed concrete with single-tooth nozzle is higher than that with square nozzles. (2) The failure cracks of specimens with square nozzle propagated horizontally in a straight line, while those of single-tooth interlocking specimens exhibited a serrated pattern along the interlocking interface. (3) The interlayer interfacial tensile strength formulas can effectively estimate the interlayer interfacial tensile strength of single-tooth interlocking 3D printed concrete. These findings provide methods and empirical insights for subsequent theoretical analysis and the establishment of calculation formulas for the strength of interlocking 3D printed concrete.