Multidepth deflectometers (MDDs) were successfully used to assess the relative damage of dual and wide base single tires. In this study MDDs were installed in two in-service asphaltic concrete highways (one thick, one thin) to measure the pavement response to vehicle loading. A specially configured 3S2 truck was used in the study. It is an 18-wheel water tanker that was converted to a 14-wheel tanker for this study. For the first set of data collection, dual tires were used on the tandem drive axle with wide base single tires on the tandem trailer axle. For the second set, wide base single tires were used on the tandem drive axle and dual tires on the trailer axle. Deflections measured at several depths within the pavement by MDD under dual and wide base single tires were used to calculate average vertical compressive strains. The Asphalt Institute subgrade limiting strain criteria were used to estimate the reduction in pavement life that will occur by using the wide base single tires in place of duals. Wide base single tires were found to be more damaging on both tandem drive and tandem trailer axle positions. At a speed of 55 mph and equivalent axle loading, it was found that the wide base single tires (trailer axle) reduced the anticipated pavement life on the thin and thick sections by a factor of between 2.5 and 2.8 over that predicted for standard dual tires. (Author/publisher)
Abstract