Safe highway operations are one of the major concerns of pavement engineers and authorities. The reduction of skid resistance during rainy weather poses high risk for safe driving. Wet skid resistance varies under different rainfall intensities and is influenced by many factors such as permeability of asphalt material, pavement geometric design, and tire operating conditions. Empirical studies could offer useful understanding of mechanisms of wet skid resistance and its influencing factors, however, the applicability of the empirical relationships are restricted as soon as there is a change in one of the relevant factors. In recent years, the advancement of the finite element tools has enabled researchers to simulate the tirefluid-pavement interaction in a more realistic way. However, to the best of the authors’ knowledge, the current available numerical models either do not include the real microstructures of the pavement or ignore the water infiltration through the pavement voids in the simulations. Therefore, this paper aims to providing a numerical tool to evaluate the wet skid resistance at various rainfall intensity conditions considering the effects of pavement geometric design, tire tread design and tire operating conditions. The surface characteristics and porous microstructures of the pavement are included in the model in a way that both the vertical water flow into the asphalt concrete and surface flow on the pavement can be captured in the simulation. The effects of several pronouncing influential factors as mentioned above are quantified. Such a model upon validation is expected to provide an easy and reliable tool for pavement engineers to evaluate wet skid resistance under rainy weather more accurately which can be incorporated into pavement management systems for safety highway operation.

Introduction

Safe highway operation is of prime importance for most of the road agencies, road institutions and road organizations. According to the reports, approximately 14% of the fatal road accidents occur under wet weather conditions [1,2]. During wet weather driving conditions, the water on the pavement acts as a lubricant which reduces the contact area at the tire-pavement interface [3,4]. As a consequence, skid resistance decreases or in other words chances of skid related traffic accidents increases on wet pavements as compared to dry pavements. The adverse effect of the presence of a water film on skid resistance has been highlighted in many research studies [5,6]. In general, higher rainfall intensity results in greater water accumulation over the pavement [7,8]. . Further, a combination of critical water film thickness and vehicle speed may result in significantly low skid resistance, which has been widely reported as the main cause of wet weather-related accidents [9,10]. Hence, it is necessary for road authorities and organizations to evaluate wet skid resistance at different rainfall conditions more accurately.