硫酸盐侵蚀水泥净浆的裂纹扩展原位成像：X-CT延时显微镜

In-situ dynamic imaging of microcrack development is critical for elucidating fracture origination and propagation mechanisms, yet remains a universal challenge. Moreover, continuous long-term imaging spanning months or even years has, to date, remained unreported. Herein, we propose an X-ray computed tomography (X-CT) method enabling continuous imaging of the cracking process of months. For sulfate attack-induced cracking progression in hardened cement paste, the temporal progression was converted into spatial coordinates along the sulfate-penetration direction via controlled sulfate diffusion kinetics, establishing a microscale "time-lapse microscope". Real-time visualization reveals ionic penetration and crack pathways among multiphase hydrates composites, and also the cracks network development process from nucleation to percolation. Greyscale analysis confirms the formation of sulfate-filling low-density (LD) hydrates, which generates interconnected networks serving as preferential fracture channels. The crack propagation rate is quantified for the first time, 36 ~ 77 μm/day. This platform pioneers continuous spatiotemporal analysis of fracture dynamics and has scalability for the study of crack propagation of other structural materials.