We aim to investigate the mechanical properties and crack propagation modes of 3D printed sandstone after high temperature, focusing on the alteration of furan resin during heating. Unlike the most current printed sandstone studies that are conducted at room temperature, we attempt to explore the performance of the heated printed sandstone, dominated by the furan resin. The heated 3D sandstones are investigated with a series of sophisticated in-door experiments at macro, meso, and microscopic levels. It is found that the uniaxial compressive strength and splitting tensile strength of the printed sandstones reached the maximum of 150 °C, at which the furan resin transforms from solid to liquid state, enabling to bond more sand particles. This is followed by the studies of crack propagation patterns and mechanical properties of heated specimens, where man-made cracks of different inclination angles are prefabricated and uniaxial compressive strengths are conducted. The results indicated that the peak strength of the cracked specimens first decreases and then increases with the increases of cracks inclination angle after heating. Furthermore, an X-ray computed tomography image is constructed, showing the difference between the internal fracture and the apparent fracture of the specimen. Our above findings show that these well-fabricated and easy-to-observing printed specimens could, to some extent, reflect heated natural sandstone behaviours, such as strength, crack initiation, and propagation. Nevertheless, when heated to 300 °C, the furan resin is becoming further dehydrated, almost losing its bonding capability and so the printed sandstone's initial structure could not be maintained any longer.

我们旨在研究高温后3D 打印砂岩的力学性能和裂纹扩展模式，重点关注加热过程中呋喃树脂的变化。与目前在室温下进行的最新印刷砂岩研究不同，我们试图探索以呋喃树脂为主的加热印刷砂岩的性能。通过一系列复杂的宏观、中观和微观层面的室内实验，对加热的 3D 砂岩进行了研究。发现单轴抗压强度和打印砂岩的劈裂抗拉强度达到了最大值 150°C，在此温度下呋喃树脂从固态转变为液态，从而能够结合更多的砂粒。随后研究了裂纹扩展模式和加热试样的力学性能，其中预制了不同倾角的人造裂纹并进行了单轴抗压强度。结果表明，裂纹试样的峰值强度随着裂纹倾角的增加而先减小后增大。此外，X射线构建计算机断层扫描图像，显示试样内部断裂和表观断裂之间的差异。我们的上述研究结果表明，这些制作精良且易于观察的印刷标本可以在某种程度上反映加热的天然砂岩行为，例如强度、裂纹萌生和扩展。然而，当加热到 300 °C 时，呋喃树脂进一步脱水，几乎失去其粘合能力，因此打印砂岩的初始结构无法再保持。