Effect of traffic overloading and stiffness of unbound aggregates on pavement performance

Abstract

This study explores the damaging influence of traffic overloading, over inflated truck tires and properties of unbound pavement layers on the performance of flexible pavements. Field data pertaining traffic loading, pavement geomaterials and climatic conditions from Pakistan was analyzed as a case study using the Mechanistic-Empirical (M-E) design framework based on General Analysis of Multi-layered Elastic Systems (GAMES). Results were presented in terms of Relative Damage Factors (RDFs). Based on the analysis of results it was found that the performance of flexible pavements is sensitive to not only traffic loading and tire inflation pressure, but also significantly to the stiffness of unbound pavement layers. The damaging influence of increase in tire pressure keeps on magnifying with each axle load increment. The flexible pavement performance against distresses such as fatigue cracking and rutting is significantly affected by the stiffness of unbound base course and subgrade, respectively. The Design RDF for the Legal axle load (118 kN) and the mean observed axle load (145 kN) on single axle with dual tires, with mean observed tire pressure of 896 kPa was 5.80 and 11.95, respectively. The damage factors derived in this study can be readily used for network level pavement management.