Effect of Subgrade Stabilization on Pavement Design: Material Optimization and Economic Impacts

The objective of this research was to evaluate the effect of subgrade stabilization on the flexible pavement design. The stabilizer used for the study was naturally derived mineral stabilizer, making it a sustainable alternative to the currently employed soil stabilizers. The scope of this study included the evaluation of improved properties of stabilized subgrade through Proctor compaction, UCS, and CBR tests; followed by pavement design as per IRC 37: 2018; and then economic analysis. The experimental results indicated that an addition of 4% mineral stabilizer increased the CBR by 15 times. Further, an overall thickness reduction of ~30 and 40% was observed with 2 and 4% stabilization, respectively. The associated material optimization was in order of 45% for low and medium traffic levels, and 58% for high traffic levels at 4% stabilization. Economic analysis based on the construction cost of materials showed 23 and 30% reduction when soil was stabilized with 2 and 4% stabilization, respectively, as compared to untreated soil. Overall, this study illustrated the effect of subgrade stabilization with mineral stabilizer on the pavement design and its associated economic impacts.