Fatigue resistance of asphalt binders and the correlation with asphalt mixture behaviour

The prediction of asphalt pavements performance in relation to the main distresses has been proposed by different researchers, by means of laboratory characterisation and field evaluation. With respect to fatigue, there are different approaches to determine what failure criterion to be considered, what testing conditions to be used and which specimens' geometry to be produced. Tests performed in asphalt binders and mixtures have been recommended to characterise the fatigue resistance, and correlations among the several scales are proposed in order to make it more practical and more precise to predict the performance of asphalt layers. In terms of laboratory fatigue characterisation of asphalt mixtures, some of the most common tests are the four-point bending beam, diametral compression, the push-pull tests, among others. The characterisation of asphalt binders is also relevant, since fatigue is dependent on their rheological characteristics. Linear viscoelastic parameters of the binders, time sweep and amplitude sweep tests were used to rank three asphalt binders (one neat 30/45 penetration grade binder; one SBS-modified binder; and one highly modified asphalt, HiMA) in terms of fatigue behaviour. HiMA showed the highest fatigue resistance. One dense hot mix asphalt (HMA) mixture (prepared with the AC 30/45 neat binder) was characterised in terms of different fatigue test methods and correlated with binder tests, comparing the two scales approaches. The fatigue life of the asphalt mixture followed in agreement with results from the asphalt binder.