NUMERICAL ANALYSIS OF SKID RESISTANCE ON POROUS PAVEMENTS
Wet-weather highway traveling safety is a major concern in the modern transportation system. Porous pavements are widely used on high-speed road to improve wet-pavement skid resistance and to reduce skidding accidents. Many research works have been conducted to study the ability of porous pavements in providing better skid resistance performance as compared to conventional pavements. Most of the previous studies are experimental in nature and could not provide a mechanistic interpretation on the skid resistance behavior exhibited by porous pavements. Realizing the state-of-the-art, this paper proposes an analysis framework that can mechanistically predict the skid resistance performance available on porous pavement surfaces and to understand the critical factors involved. Two key modules are consisted in this scheme. The first module determines the water film thickness accumulated on porous pavement surfaces under a given rainfall intensity, and the second module computes the skid number on flooded porous pavements with consideration to structural mechanics, fluid dynamics and fluid-structure-interaction. The fluid flow within porous layer is captured with a simplified representation of the pore geometry. The developed framework is first validated against past experiments, and illustrative case study is then presented to provide a fundamental understanding of skid resistance development on porous pavements. It is found that porous pavement is capable to releasing hydraulic pressure underneath a sliding tire, hance to reduce the fluid uplift force acting on the tire. This is the main cause of skid resistance improvement on porous pavements.