RELATIVE EFFECT OF WIDE BASE RADIAL TYRES ON PAVEMENT PERFORMANCE

Austroads is currently funding a project, "Impact of New Heavy Vehicles on Pavement Wear and Surfacings", under its National Strategic Research Program. The project commenced in 1999/2000 and is expected to run until 2002/2003. The objectives of this project are to: determine the relative effect on pavement wear and surface life for different loads, tyre types and pressures, drive arrangements, suspension types and axle configurations typical for Australia and New Zealand; assess the likely future vehicle types and masses on the Australian road network; validate or refine models used to estimate the damaging effect of different vehicles; and, hence, develop a more rational basis for assessing the potential impacts of future vehicle configurations. This report presents a literature review of the relative effect of side base radial tyres - sometimes referred to as 'super singles', or 'wide single tyres' - on pavement performance. In particular, information was sought on their effect on thin asphalt and granular pavements with thin bituminous surfacings, which comprise 90% of the Australasian sealed road network. Most information found during a search in the literature pertained to asphalt surfacings. It is recommended that, as a result of this study, further investigation be undertaken, of: 1) how well relationships predict actual tyre contact stresses, particularly those beneath wide base radial tyres; 2) how well models, including readily available and local programs such as CIRCLY, determine, and replicate, actual tyre contact stress distributions; and 3) how well models or techniques can use the stresses determined above to predict stresses and strains within the pavement structure, including those beneath, and near, the tyre contact patch.