Effect of Pre-Cracks on Cement Paste Degradation under External Sulfate Attack
Cement-based materials are vulnerable to external sulfate attack, particularly when pre-existing cracks are present in the matrix. These cracks serve as pathways for aggressive ions, accelerating chemical degradation and compromising durability. The present study investigates how pre-cracks influence the microstructural and mechanical evolution of cement pastes exposed to a low concentration sodium sulfate solution. Advanced analytical techniques, including SEM-EDS, microindentation, and microtomography, were employed to understand the chemo-mechanical processes driving localized degradation and crack propagation. Influence of Pre-Cracks on Ion Diffusion Pre-existing cracks significantly enhance the ingress of sulfate ions, accelerating degradation near the crack zone. The V-shaped chemical attack pattern observed indicates that cracks act as preferential channels, allowing rapid penetration of aggressive agents. This enhanced diffusion mechanism highlights the critical role ...