通过对比3D打印混凝土（3DPC）和浇筑混凝土在不同测试方向上的强度和耐久性差异，探究了3DPC硬化性能各向异性特征及其对间隔时间的依赖性.结果表明：3DPC的硬化性能存在一定的各向异性，相较于平行于打印层方向，在垂直于打印层方向上的力学性能与抗渗性更高，其各向异性的产生与打印层间的弱黏结界面以及混凝土基体内孔隙和缺陷的分布有关；延长打印间隔时间，3DPC层间界面黏结性能明显变弱；3DPC不同打印层的耐久性存在差异，相较于下层混凝土，上层混凝土密实度较低，侵蚀性介质的扩散速率更快.

By comparing the strength and durability differences between 3D printing concrete（3DPC） and casting concrete in different test directions， the anisotropic characteristics of the hardened properties of 3DPC and its dependence on the resting time were explored. The results show that the hardened properties of 3DPC have certain anisotropy， and the mechanical properties and impermeability in the vertical direction are higher. The anisotropy of hardened properties is related to the weak bonding interface between printing layers and the distribution of pores and defects in the concrete matrix. The bonding property of interlayer interface is obviously weakened when resting time is prolonged. The durability of different printing layers of 3DPC is different， the density of the upper layer of concrete is lower， and the diffusion rate of the aggressive medium is faster.

TU528.59

国家自然科学基金资助项目（U22B2076， 51878480， 52078369）；“十四五”国家重点研发计划项目（2022YFC3803104）；中央高校基本科研业务费专项资金