Analysis of fatigue life of asphalt concretes considering different types of mixtures and binders

The research described in this paper concerns the fatigue life of base course asphalt mixtures. Two mixture types were chosen for analysis: asphalt concrete and High Modulus Asphalt Concrete. Either of them contained different bitumen types, including standard pen-grade bitumens, polymer-modified bitumens (PMB) and so-called highly-modified asphalts (HiMA). Fatigue life tests were carried out and their results were used for fatigue law determination of the mixtures under analysis. Fatigue life analyses were performed both for the analysed mixtures and for typical flexible pavements. The value of the so-called shift factor was estimated to enable application in the design of pavements of the fatigue law parameters determined in laboratory. Two fatigue parameters are proposed in this research: critical strain and fatigue life ratio. They provide a more robust comparison of fatigue life determinations on bituminous mixtures by taking into consideration also the fatigue life of the pavement structure itself. The analyses conducted as part of this research enabled assessment of the fatigue life of asphalt mixtures taking account of the type of both the mixture and the bitumen it contains.