Ding Shengxuan, Li Jiren, Wang Mingqiang
School of Civil Engineering, University of Science and Technology Liaoning, Anshan 114051, China.
Materials (Basel). 2025 Jul 18;18(14):3379. doi: 10.3390/ma18143379.
As 3D concrete printing emerges as a transformative construction method, its structural safety remains hindered by unresolved issues of mechanical anisotropy and interlayer defects. To address this, we systematically investigate the failure mechanisms and mechanical performance of basalt fiber-reinforced 3D-printed magnesite concrete. A total of 30 cube specimens (50 mm × 50 mm × 50 mm)-comprising three types (Corner, Stripe, and R-a-p)-were fabricated and tested under compressive and splitting tensile loading along three orthogonal directions using a 2000 kN electro-hydraulic testing machine. The results indicate that 3D-printed concrete exhibits significantly lower strength than cast-in-place concrete, which is attributed to weak interfacial bonds and interlayer pores. Notably, the R-a-p specimen's Z-direction compressive strength is 38.7% lower than its Y-direction counterpart. To complement the mechanical tests, DIC, CT scanning, and SEM analyses were conducted to explore crack development, internal defect morphology, and microstructure. A finite element model based on the experimental data successfully reproduced the observed failure processes. This study not only enhances our understanding of anisotropic behavior in 3D-printed concrete but also offers practical insights for print-path optimization and sustainable structural design.
随着3D混凝土打印作为一种变革性的施工方法出现，其结构安全性仍然受到机械各向异性和层间缺陷等未解决问题的阻碍。为了解决这一问题，我们系统地研究了玄武岩纤维增强3D打印菱镁矿混凝土的破坏机制和力学性能。使用一台2000kN的电液试验机，制作了总共30个立方体试件（50mm×50mm×50mm），包括三种类型（角部、条纹和R-a-p），并在三个正交方向上进行了压缩和劈裂拉伸加载测试。结果表明，3D打印混凝土的强度明显低于现浇混凝土，这归因于薄弱的界面粘结和层间孔隙。值得注意的是，R-a-p试件的Z方向抗压强度比其Y方向抗压强度低38.7%。为补充力学试验，进行了数字图像相关（DIC）、CT扫描和扫描电子显微镜（SEM）分析，以探究裂纹发展、内部缺陷形态和微观结构。基于实验数据的有限元模型成功再现了观察到的破坏过程。本研究不仅增进了我们对3D打印混凝土各向异性行为的理解，还为打印路径优化和可持续结构设计提供了实用见解。
