3D printed concrete structures often exhibit considerable degree of anisotropy and inhomogeneity because of layered material deposition and inferior properties of the interlayer regions between concrete filaments. These interlayer regions, which will be called interfaces hereafter for better readability, can significantly affect overall mechanical performance of printed concrete structures. Therefore, this paper provides a critical review of recent research advances on interfaces in 3D printed concrete. Firstly, the bond between printed layers is discussed from the microscopic point of view. Thereafter, test methods suitable to evaluate interfacial bond strength within 3D printed concrete are summarized. The effects of printing parameters, material composition and other factors on the interfacial bond strength are discussed, and the corresponding modification methods are addressed. Furthermore, the existing analytical models for 3D printed concrete interfaces are compared to offer a base for structural finite element analysis. Finally, some ideas on the future research are put forward.

由于层状材料沉积和混凝土细丝之间层间区域的劣质性能，3D 打印的混凝土结构通常表现出相当程度的各向异性和不均匀性。这些层间区域，为了更好的可读性，在下文中将被称为界面，可以显着影响印刷混凝土结构的整体机械性能。因此，本文对 3D 打印混凝土界面的最新研究进展进行了批判性回顾。首先，从微观角度讨论印刷层之间的结合。此后，总结了适用于评估 3D 打印混凝土内界面结合强度的测试方法。讨论了印刷参数、材料成分等因素对界面结合强度的影响，并给出了相应的修改方法。此外，还比较了现有的 3D 打印混凝土界面分析模型，为结构有限元分析提供了基础。最后，对未来的研究提出了一些设想。