Evaluation of Deformations in Two-Layered Pavement Systems Under Monotonic Loading Using Digital Image Correlation Technique

Accurate and reliable deformation measurements are essential to understand the mechanics of any foundation system. Traditional instruments, including linear variable differential transducers (LVDTs) and potentiometers, are reliable; however, they have limited capability in certain scenarios. They provide mean values of strains and displacements at selected locations and gauge lengths; this renders inadequacy in evaluating a non-homogeneous material behavior. The main objective of this research was to emphasize on the use of Digital Image Correlation (DIC) technique for a layered foundation system to overcome the inadequacy of regular instruments. In the present study, a two-layered reinforced and unreinforced pavement systems consisting of a 300 mm thick aggregate layer (base layer) overlying a 500 mm thick sand layer (subgrade) was prepared in a test chamber of dimensions 0.9 m × 0.9 m × 1 m in length, width, and depth. A monotonic load was applied through a strip footing on the pavement layered systems, and the deformations under the loaded area were captured using DIC technique. The results were further validated using conventional measuring devices.