Early pavement failures can result from the influence of large particles on the compressive behavior of reclaimed pavement base materials, potentially leading to settlement issues. Full-Depth Reclamation (FDR) offers a cost-effective solution by stabilizing base materials through mechanical, chemical, or bituminous methods. This study examines the impact of large particles on the compressive behavior of FDR specimens using digital image correlation. The research is divided into two phases: a geotechnical investigation of pavement materials and compression tests to evaluate stress–strain behavior. Soil samples collected from the site were chemically stabilized with cement, and the optimal cement content was determined using unconfined compressive strength tests of mud-mortar specimens with various mix ratios, in accordance with IRC SP:89–2010. Scanning Electron Microscopy (SEM) identified Halloysite clay mineral in the samples, which were poorly graded. Coarse aggregates ranging from 40 to 80 mm were incorporated to simulate the presence of large particles. The stress–strain behavior of the FDR specimens was analyzed using Digital Image Correlation (DIC), a non-intrusive technique for full-field deformation and strain measurement. Compression tests were conducted, and surface deformations were captured through digital imaging. The analysis revealed non-linear stress–strain behavior, with strain localization at the sites of large particles leading to fracture and failure. Additionally, strain variations at different depths were examined to assess the impact of large particles on the performance of FDR specimens. This research enhances our understanding of how large particles affect the compressive behavior of FDR materials and provides insights for optimizing FDR techniques to improve pavement performance and durability.