Modeling Hydrology and Reactive Transport in Roads: The Effect of Cracks, the Edge, and Contaminant properties

Abstract

The goal of this research was to provide a tool for regulators to evaluate the groundwater contamination from the use of virgin and secondary materials in road construction. A finite element model, HYDRUS2D, was used to evaluate generic scenarios for secondary material use in base layers. Use of generic model results for particular applications was demonstrated through a steel slag example. The hydrology and reactive transport of contaminants were modeled in a two-dimensional cross section of a road. Model simulations showed that in an intact pavement, lateral velocities from the edge towards the centerline may transport contaminants in the base layer. The dominant transport mechanisms are advection closer to the edge and diffusion closer to the centerline. A shoulder joint in the pavement allows 0.03 to 0.45 m3/day of infiltration per meter of joint length as a function of the base and subgrade hydrology and the rain intensity. Scenario simulations showed that salts in the base layer of pavements are depleted by 99% in the first 20 years, whereas the metals may not reach the groundwater in 20 years at any significant concentrations if the pavement is built on adsorbing soils.

Department

Civil Engineering

Publication Date

10-1-2007

Journal Title

Waste Management

Publisher

Elsevier

Digital Object Identifier (DOI)

10.1016/j.wasman.2007.03.018

Document Type

Article

Rights

© 2007 Elsevier Ltd. All rights reserved

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