Verification of the Enhanced Integrated Climatic Module Soil Subgrade Input Parameters in the MEPDG

Authors

Alain El Howayek, Purdue UniversityFollow
Daniel Muschett, Purdue UniversityFollow
Tommy Nantung, Indiana Department of TransportationFollow
Jusang Lee, Indiana Department of TransportationFollow
Marika Santagata, Purdue UniversityFollow
Antonio Bobet, Purdue UniversityFollow

Recommended Citation

El Howayek, A., Muschett, D., Nantung, T., Lee, J., Santagata, M., & Bobet, A. (2016). Verification of the enhanced integrated climatic module soil subgrade input parameters in the MEPDG (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2016/08). West Lafayette, IN: Purdue University. https://doi.org/10.5703/1288284316331

DOI

10.5703/1288284316331

Abstract

At the beginning of 2009, INDOT adopted the Mechanistic-Empirical Pavement Design Guide (MEPDG) method to study the tong-term pavement performance. The implementation of this new design approach led to difficulties for the pavement to pass the INDOT performance criteria; in particular pavement roughness (IRI) when A-6 or A-7-6 soils were considered as subgrade. This study focuses on investigating the influence of the soil input parameters in the Enhanced Integrated Climatic Model (EICM) on the prediction of the soil resilient modulus (M_R) in the MEPDG. A total of four sites located around the state of Indiana are used to propose/validate the observations and conclusions made in the research.

The study shows that (1) for the climatic conditions existing in Indiana, the location of the water table does not affect the value that the MEPDG uses for the subgrade M_R; (2) the gravimetric water content is the most influential parameter on the EICM since it is directly related to the optimum degree of saturation of the subgrade; and (3) For A-7-6 soils, the overall deformation of the pavement structure is controlled by the subgrade (~80% of total deformation).

In order to properly model the pavement structure, the M_R input into the MEPDG for the subgrade should represent the optimum condition. This value will then be reduced within the EICM to reflect actual site conditions; and the M_R input into the MEPDG for the treated layer should be a constant (i.e. not affected by EICM) and with PI and P₂₀₀ values that are representative of the soil after treatment, given that the fines content and plasticity of a chemically-treated soil tend to decrease with treatment.

Report Number

FHWA/IN/JTRP-2016/08

Keywords

resilient modulus, subgrade, MEPDG, EICM, SWCC, fine-grained soil, long-term pavement performance

SPR Number

3806

Performing Organization

Joint Transportation Research Program

Sponsoring Organization

Indiana Department of Transportation

Publisher Place

West Lafayette, Indiana

Date of this Version

2016