Development of the Soil-Dielectric Characteristic Curve for Predicting Suction in Base Course Materials

This study presents the development of the soil-dielectric characteristic curve (SDCC), a predictive model for estimating soil suction in base course materials using dielectric constant measurements. The SDCC defines the relationship between dielectric constant and suction through an S-shaped curve, established via laboratory testing with a percometer and the filter paper method. To enhance field applicability, the model incorporates methylene blue value (MBV) and percent fines content (PFC) into regression-based fitting parameters, enabling suction prediction without direct suction testing. The framework integrates empirical measurements, volumetric dielectric modeling, and statistical analysis to generate material-specific SDCCs across a variety of aggregate types. Validation results showed strong agreement between predicted and measured suction values. This method supports rapid evaluation of unsaturated behavior in base materials and offers a practical tool for improving quality control and moisture management during the construction of pavement subgrades, base layers, and embankments.