Impact of Wide-Base Single Tires on Pavement Damage

Dual tires have traditionally been used to limit pavement damage by efficiently distributing axle loads over a larger contact area than single tires. However, in recent years, the trucking industry, stating economic and safety benefits, has promoted the use of wide-base single tires. The Super Single tire, an early type of wide-base tire, proved inadequate and induced excessive pavement damage. By contrast, the new generation wide-base tires have contact areas that approach those of dual tires and offer the potential for improved performance. The Florida Department of Transportation investigated the pavement damage potential of four tire types, including a conventional dual tire (11R22.5), a Super Single (425/65R22.5), and two newly designed wide-base single tires (445/50R22.5 and 455/55R22.5 respectively). A controlled accelerated pavement testing program, in addition to theoretical modeling, was performed to determine critical pavement response parameters. Pavement damage was measured in terms of rutting and fatigue cracking (bottom-up or top-down), the predominant distresses in Florida. The investigation revealed that the 455-mm wide-base tire performed as well as the dual tire. By comparison, the 445-mm wide-base tire was shown to create more rut damage on a dense-graded pavement surface and was predicted to create more bottom-up cracking than a dual tire. As expected, the Super Single induced the most damage to the pavement.