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Porous asphalt is a standard asphalt built on aggregate storage bed which allows water to drain through it and reduces stormwater runoff. However, porosity of the porous asphalt and the storage bed may be effectively reduced due to trapping suspended solids from the water or from the asphalt damage. In this paper, we present mathematical modeling and numerical simulation of flow and damage of porous asphalt-paved roads. A mathematical model to describe the fine-particles transport carried by a two-phase flow in a porous medium is presented. The buoyancy, capillarity, and mixed relative permeabilities correlations to fit with the mixed-wet system are considered. Throughout this investigation, we monitor the changing of the fluids properties such as water saturation and solid properties such as porosity and permeability due to trapping the fine-particles.

The impervious asphalt-paved roads may store significant amounts of thermal energy during summer. The stored thermal energy may be transferred to stream waters during runoff events. Moreover, as a result of fluctuations in ambient air temperatures—diurnal and seasonal, intensity of solar radiation of the asphalt-paved, a significant deformation of asphalt-paved may occur due to the heat and mass transfer between asphalt and water. On the other hand porous (pervious, permeable, or open-graded) asphalt is standard asphalt with reduced sand or fines that allows water to drain through it. Pervious asphalt built on aggregate storage bed reduces stormwater runoff. In addition to reducing runoff, this effectively traps suspended solids and filters pollutants from the water. The stormwater flows through the asphalt to the layer of crushed stone aggregate bedding and base that supports the asphalt while providing storage and runoff treatment. The use of porous asphalt can potentially reduce additional expenditures and land consumption for conventional collection, conveyance, and detention stormwater infrastructure. Compared to the lifetime of dense graded asphalt concrete roads, the lifetime of porous asphalt concrete is less [

Researchers have done many attempts to predict these phenomena experimentally and numerically; however, there is no study that considers the possible porosity and permeability reduction. So, in order to keep porous asphalt and its storage bed efficient, considering these kinds of effects may lead to interesting results. In the current work, we introduce modeling and numerical simulation of fine-particle transport in two-phase flow in porous asphalt-paved roads.

The basic equations that govern the flow of the two-phase flow in porous media are mass conservation equation and constitutive equation (Darcy’s law). The two-dimensional governing equations may be written as^{2}] is the absolute permeability, ^{3}] is the density,

On the other hand, a mathematical model is developed to describe the fine-particles transport carried by two-phase flow in porous media. Assuming that we have a number

In order to get physical insights for the problem under consideration, we consider that typical cross-section for pervious pavement system consists of six porous layers (Figure

Typical cross-section for pervious pavement system.

For the capillary pressure we used the general correlation

The transport equation for the interval ^{−1}, ^{−1}, ^{−1}, ^{2}/s. The inlet particles concentration values are

Figure

Water saturation against the height with various imbibition times and inlet concentrations.

The normalized particles concentration is plotted in Figure

Normalized particles concentration against height with positive/minus

Figures

Permeability ratio against the height with various imbibition times.

Porosity ratio against the height with various imbibition times.

In this pape, we presented numerical modeling and simulation of particle transport in two-phase flow in porous asphalt-paved roads. Numerical experiments have been performed to explore these phenomena and to study the possible porosity and permeability variations. We found that both the permeability and the porosity are reduced due to the precipitation of the particles on the pores walls. These results may help engineers to keep porous asphalt and its storage bed efficient by looking for cleaning methodologies to avoid media blocking.

The authors would like to thank the Institute of Scientific Research and Revival of Islamic Heritage, Umm Al-Qura University, for supporting the Project no. 43208015.