01661418

Component

Light Weight Deflectometer (LWD) has been commonly used for in-situ determination of stiffness properties and evaluating the load-carrying capacity of pavement layers, particularly unbound materials. However, recent studies revealed the strong correlation between permanent deformation of an unbound layer and its shear strength parameters (friction angle, ϕ, and cohesion, c). In addition, analysis of instantaneous shear failure in asphalt concrete pavement layers subjected to the non-standard superheavy vehicles requires reliable estimates for strength parameters of pavement layers, particularly subgrade. In this study, a novel LWD-based methodology for estimating the in-situ shear strength parameters of the pavement subgrade layer contained within the loaded or influenced zone which contributes to the long-term pavement performance has been proposed. Extension of commonly accepted hyperbolic stress-strain relationship along with the consideration of nonlinear stress dependency of subgrade materials under multiple LWD load levels have been incorporated in the proposed methodology. The methodology was validated using numerically simulated LWD testing at multiple load levels for two different subgrade materials. It was also verified for two additional subgrade soils based on data collected from LWD testing at University of Nevada, Reno large-scale facility as well as measurements obtained from FAA’s National Airport Pavement Test Facility (NAPTF). The proposed LWD-based methodology provides a reasonable estimate of the in-situ shear strength parameters of the subgrade material.

This paper was sponsored by TRB committee AFS20 Standing Committee on Geotechnical Instrumentation and Modeling.

18-05437

English

18p

2018

Transportation Research Board 97th Annual Meeting

Digital/other

Figures; Photos; References; Tables

Asphalt concrete pavements; Deflectometers; Pavement layers; Shear strength; Stresses; Subgrade (Pavements)

Geotechnology; Highways; Pavements

Transportation Research Board Annual Meeting 2018 Paper #18-05437

TRIS, TRB, ATRI

Jan 8 2018 11:23AM