Desiccation cracking behavior of polypropylene fiber-reinforced clayey soil

Improvement of the crack resistance of clayey soils by fiber reinforcement was investigated using initially saturated and fiber-reinforced soil specimens subjected to desiccation. An image-processing technique was used to quantitatively describe the effect of fiber addition on the geometrical and morphological characteristics of crack patterns. The results show that the soil desiccation cracking behavior was significantly influenced by fiber inclusion: the crack resistance was significantly improved and the amount of desiccation cracks was significantly reduced by fiber addition. Generally, the surface crack ratio (surface of cracks to total surface), number of clods, average length and width of cracks, and crack network connectivity decreased with increasing fiber content, while the average area of clods, number of nodes per unit area, number of crack segments per unit area, crack density, and specimen integrity increased. During crack propagation, the surface crack ratio increased with decreasing water content and finally reached stabilization. Comparison between the surface crack ratio of the natural soil specimen and that of the fiber-reinforced soil specimen showed that the former was always higher than the latter. The fiber length was found to have an insignificant effect on the soil desiccation cracking behavior.