Effect of heavy traffic loading on predicted pavement fatigue life

Abstract

Fatigue cracking is one of the dominant failure modes of asphalt concrete pavements. There are a number of analysis and design methods that can be used to optimize pavement sections for this kind of distress. Most of these methods incorporate advanced material property predictive models. However, traffic loading, which has been identified as a primary contributing factor in causing fatigue cracking, is characterized relatively simplistically. There is a concern in light of recent advancement in traffic characterization, and tire inflation pressure surveys that existing methods might not be adequate. The objective of this paper is to evaluate and quantify the effects of truck traffic characterization in axle load spectra and high tire inflation pressure levels on predicted fatigue cracking performance. This was achieved by evaluating a number of pavement sections using the mechanics-based fatigue cracking analysis framework. The studied traffic characterization approaches are ESALs, axle load spectra with and without traffic seasonal variations and three levels of tire inflation pressures. It is evident from the result that higher tire inflation pressure and traffic characterization using axle load spectra induce more damage and subsequently early crack initiation time.