Summary:

Dual tires have been the trucking industry standard for many decades. For this reason, existing modelling of the stresses imparted to the pavement through the tires is based on dual tires. However, the freight industry has started to use wide-base single tires, also known as super single tires (SST) because of their economic benefits and safety advantages. Therefore, SSTs may gradually replace conventional dual tires. Early design types of SSTs induced excessive pavement damage, especially to flexible pavements. These types of SSTs can generate much higher vertical contact stresses as compared to traditional dual tires, resulting in more significant deformations and more severe damage in bound and unbound layers within a pavement structure. Subsequently, the latest generation of SSTs now have contact areas that are like traditional dual tires and potentially offer improved performance. Therefore, these SSTs would inflect less bottom-up cracking in the asphalt concrete layer and less permanent deformation in all pavement layers. It is not clear what effect SSTs have on dynamic loading when the pavement surface exhibits high surface roughness, (measured in terms of the International Roughness Index (IRI)). Moreover, weight measurements obtained by roadway Weigh-in-Motion (WIM) sensors may have errors as compared to the actual axle load for such tires. Therefore, there is a need to investigate the impact of such wide-based tires on pavement performance for Michigan’s climate and construction practices, identifying the impacts that these have on the current MDOT flexible and rigid pavement design methods. For example, the presence of SSTs may influence the axle load spectra (ALS) to be used in ME analysis and load equivalency factors (LEF) for the AASHTO design method.

Publications:

• Final Report

• Spotlight

Research Manager	Project Manager	Performing Organization
Andre Clover	Justin Schenkel	Michigan Technological University