A comparative study of desiccation-induced shrinkage and cracking behavior of clayey soils from a cracked road

The shrink-swell behavior of clayey soils is a major concern in geotechnical engineering, particularly due to its role in the formation of desiccation cracks that undermine the structural integrity of road pavements. This study investigates the shrinkage and desiccation-induced cracking behavior of three different clayey soils: a swelling clay (calcium-rich Bentonite), a non-swelling clay (Kaolinite), and a clayey soil sampled from the cracked RD105 marsh road in Southwest France (Esnandes). Linear shrinkage tests (NF P 94–060–2) and 2D Digital Image Correlation (DIC-2D) were employed to monitor and quantify shrinkage deformation and crack propagation during desiccation. Microscopic (SEM/EDS) and mineralogical (XRD) analyses provided insights into the material properties influencing desiccation behavior. The results revealed substantial differences among the soils. Bentonite exhibited the highest volumetric shrinkage (47 %) and the most extensive cracking, characterized by a Crack Surface Ratio (CSR) of 32 % and an average crack width of 4.7 mm. Esnandes showed intermediate behavior, with 41 % volumetric shrinkage, a CSR of 14.5 %, and an average crack width of 3.5 mm. Kaolinite, by contrast, exhibited minimal shrinkage (16 %) and no significant cracking. The drying kinetics analysis indicated that Kaolinite reached its shrinkage limit within 1.4 days, Esnandes within 2.6 days, and Bentonite within 5.5 days. The final residual water content stabilized at 10 % for Bentonite, 3 % for Esnandes, and 0.1 % for Kaolinite. These findings highlight the critical role of soil mineralogy in governing shrinkage and cracking mechanisms, underscoring the importance of tailored stabilization strategies when constructing on expansive clayey soils.