Enhanced pavement design process to incorporate moisture management geotextiles: a comprehensive mechanical-hydro-mechanical modeling and design integration (part B)

In Part A of this study, a mechanical model was developed to capture the mechanical reinforcement effects of Moisture Management Geotextiles (MMG). Part B introduces a comprehensive Mechanical-Hydro-Mechanical (MHM) model to integrate the mechanical (Part A) and hydraulic (Part B) stabilizations provided by MMG. The hydro-mechanical model employs a system dynamic model (SDM) comprising two main components: a hydrological model simulating moisture movement withing pavement structure; and a geotechnical model determining moisture-dependent material properties. The mechanical part assesses pavement structural performance based on the SDM’s outputs. Validation against Hydrus-1D demonstrated high accuracy in simulating moisture dynamics (R2 = 0.96). Seasonal analyses revealed that MMG enhances the unbound granular layers and subgrade resilient modulus, especially during high-precipitation seasons. Fourteen demonstration cases were used to show the improvement that integrating MMG in pavement context will provide. Adjusted pavement designs were validated using both non-linear finite element and layered elastic analysis models, confirming the effectiveness of thickness adjustments (R2 = 0.95). Comparative analyses indicated that MMG reduces compressive strains on top of the subgrade and increases pavement rutting life by up to 200 % for demonstration cases. The benefits of MMG were incorporated into the AASHTO 1993 design method, resulting in increases in equivalent single axle load capacities and structural enhancements. Automated Python-based tools were developed to facilitate the incorporation of MMG into both mechanistic-empirical and empirical pavement design approaches, providing a user-friendly environment without requiring in-depth knowledge of complex models. This research bridges the gap between innovative geosynthetic materials and established design methodologies, offering a robust tool for engineers to create durable and resilient pavements.