Dynamic Wheel Loads on Superpave Pavements

Dynamic wheel load applied on the pavement surface by heavy vehicles is one of the major causes of pavement damage. Several factors, such as, road roughness, speed, and vehicle design influence the dynamic wheel loads. This study deals with the dynamic wheel loads (DWLs) and dynamic load coefficients (DLCs) (the standard deviation of the dynamic wheel loads divided by the static wheel load) generated by the trucks with varying load configuration in response to the roughness profiles of newly built Superpave sections. Forty Superpave sections, each 161 m long, were selected for the study. A heavy vehicle simulation software, TruckSim, was used to calculate the DWLs and DLCs for three different truck types corresponding to the roughness profiles at two different time periods. The simulation was done at three different truck speeds. International Roughness Index (IRI) was used to represent the road roughness. The results show that the extent of dynamic wheel loads induced on the Superpave sections and the corresponding DLCs depend upon the truck size and weight, road roughness, and driving speed. However, the interrelationships among IRI, DWLs and DLCs are complex. Superpave sections with IRI greater than 1.66 m/km generated significantly higher DWLs and DLCs than those with IRI less than 1.66 m/km. Higher speed also tends to generate higher maximum dynamic wheel loads and DLCs.