Critical Rut Depth for Pavement Maintenance Based on Vehicle Skidding and Hydroplaning Consideration

Abstract

Rutting is a major form of pavement distress in asphalt pavements. The main concern with rutting has been related to driving safety. Many highway agencies and researchers suggested that pavement rutting could lead to vehicle hydroplaning and loss of skid resistance in wet weather. However, to date no theoretical basis has been established for an analytical assessment of the severity of rutting for the purpose of pavement maintenance and rehabilitation. Most highway agencies classify rut severity on the basis of engineering judgment or field experience. This paper presents an analytical procedure to assess the severity of rutting based on vehicle skidding and hydroplaning analysis. It considers the worst-case scenario where a rut is filled with water and analyzes (1) if a car will hydroplane at a given speed; and (2) the length of braking distance required for the car traveling at the given speed. A finite-element simulation model is adopted to perform the analysis. For a given rut depth filled with water, the computer model computes the hydroplaning speed for a typical passenger car, and the required braking distance for the car traveling at a known speed. It was found that depending on the rut depth and the surface frictional property of a pavement, the severity classification of a rut may be governed by either hydroplaning risk or safety requirement of braking distance. The traditional method of using the same set of critical rut depths for all pavement sections in a road network is not ideal for effective handling of rutting maintenance.