Methylene Blue Value as Rapid Proxy for Geotechnical Characterization of Base Course Aggregate: Physics-Based Models and Experimental Validation

Abstract

Rapid determination of geotechnical parameters is essential for quality control of base course aggregates in transportation infrastructure construction. This study presents theoretical models and experimental validation for determining the specific gravity, liquid limit, plastic limit, plasticity index, activity ratio, and compression index of base course aggregates using the methylene blue value (MBV) as a proxy indicator. The framework builds on the Juárez-Badillo compressibility equation and fluid mechanics principles to establish physics-based correlations between MBV and aggregate properties. Validation with 270 tests on nine aggregate sources from Texas quarries (limestone, sandstone, and caliche) demonstrated strong correlations across all parameters. The specific gravity model, which integrates liquid limit and plasticity index, achieved a mean absolute error below 3%. Compared to traditional methods requiring 18–35 h, MBV-based testing reduced time to under 10 min, a 99.5% improvement. Beyond efficiency, the models offer a physical interpretation of soil–water–clay interactions in low- to moderately plastic materials ( P I < 20 % ), thereby confirming their reliability across diverse base course aggregate sources. Together, these validated models offer a rigorous and practical tool for rapid quality control of base course aggregates in pavement construction.