Effect of axle configurations on fatigue and faulting of concrete pavements

Abstract

The new mechanistic-empirical pavement design method in the US does away with the ESAL concept and employs instead the concept of axle load spectra. The state of Michigan allows several heavy truck configurations with up to 11 axles and large axle groups with as many as 8 axles within one axle group. However, very little research has been done on the effect of different axle configurations on pavement damage. In this paper, the fatigue life of concrete beams was determined in the laboratory for different axle configurations. The results indicate that the normalized fatigue damage per axle for larger axle groups is less than the single axle under identical stress ratios. The damage is much lower when considering the reduction of stress under multiple axles. In addition, a mechanistic analysis was performed for faulting and fatigue with and without curling. The results showed that class 13 trucks with multiple axles are less damaging in fatigue than class 9 trucks, while the most damaging truck is that of class 11 with only single axles. The results from faulting analysis showed that class 13 trucks are more damaging than class 9 truck, while the least damaging truck is that of class 11.