Deformation of asphalt surfacings under stationary and slow-moving traffic

The effect of traffic speed and type of loading on the deformation of asphalt surfacings was investigated. An asphalt indentation test was used to simulate the effect of stationary and slow-moving traffic on asphalt deformation. Indentation tests were carried out under both static and cyclic loading conditions. Static indentation tests were carried out by applying a constant load for a period of time (creep test) to the surface of an asphalt specimen. Cyclic indentation tests were carried out at different loading frequencies to simulate various traffic speeds. Standard tests, including wheel tracking and cyclic compression tests, were also performed. It was found that the deformation of asphalt surfacings under static loading depended on the duration and magnitude of the contact pressure. In addition, deformation increased when the frequency of loading was reduced – that is, when traffic speed decreased. Indentation tests were found to be more suitable than standard tests to characterise the resistance of asphalt surfacings to deformation due to static and slow-moving loads. These tests can be used to better select asphalt mixtures for the type of loading and traffic conditions expected on site.