Interlayer Fracture Properties of 3D-Printed Cement-Based Structures (2025-10)¶

3D printing technology presents new opportunities for the construction industry; however, the weak interlayer bonding significantly limits the overall mechanical performance of printed structures. To address the incomplete understanding of interfacial behavior, this study systematically investigates the factors influencing interlayer adhesion in 3D-printed cement-based materials and reevaluates the underlying mechanisms. Specifically, the effects of static yield stress, printing height, time intervals, and moisture loss on interfacial fracture behavior are analyzed. Three-point bending tests, X-ray computed tomography (XCT), and scanning electron microscopy (SEM) are conducted to evaluate interfacial fracture toughness, fracture energy, and microstructural characteristics. The results indicate that both printing height and static yield stress influence fracture performance through changes in the interfacial pore structure, and their effects can partially compensate each other. Time intervals significantly degrade interfacial performance. Even before initial setting, a 40-minute interval will lead to a 21.3 % decrease in the interfacial fracture toughness. Moisture loss further disrupts the bridging between pore structures and hydration products, exacerbating interfacial deterioration. This study provides a theoretical basis for optimizing the interfacial performance of 3D-printed cement-based materials and highlights the importance of minimizing the simultaneous occurrence of adverse factors in practical applications.