Early Durability Assessment of FDR Pavement Base Stabilized with Fly Ash–GGBS Geopolymer Binder

Full depth reclamation (FDR), incorporating geopolymer binders, offers a sustainable solution for rehabilitating deteriorated pavement while sequestering hazardous industrial byproducts and enhancing structural capacity. However, conventional durability assessment tests, such as wetting–drying (W-D) and freezing–thawing (F-T) cycles, are labor and time-intensive, limiting large-scale implementation. This study explored alternative durability methods viable for cement and geopolymer stabilized bases to address this gap. Geopolymer binders were synthesized using varying proportions and concentrations of Class F fly ash, ground granulated blast furnace slag (GGBS), and sodium hydroxide, respectively. Cylindrical specimens of mixes 7C and BGP2 exhibited 7 day unconfined compressive strengths of 3.98 and 4.17 MPa, respectively, with corresponding cube strengths of 5.04 and 5.14 MPa. Correlation analysis demonstrated strong linear dependencies among W-D, F-T, and vacuum saturation test results, indicating methodological reliability. ANOVA substantiated statistically significant distinctions among specimens, validating discrete durability conditioning. The findings suggest that the vacuum saturation test is a quick, reliable, and cost-effective alternative for assessing geopolymer-stabilized base layers’ durability in tropical and snowbound regions.