Several studies show that properties of Hot Mixture Asphalt (HMA) mix design materials, aggregate gradation and volumetric properties had an influence on their resistance to rutting. However, Volumetric Properties these properties do not impact in the same way this performance. For a given aggregate type, an infinity aggregate gradation type can be observed, and for each type of HMA several types of bituminous binder can be used. This article aims to measure the evolution of resistance to rutting according to the three main classes of National Cooperative Highway Research Program (NCHRP) aggregate gradation (dense-graded, fine-graded and coarse-graded).<span “=””> To this end, a study was conducted on the measurement of rutting resistance for eight bituminous mixtures manufactured with two bitumen types and two types of manufacturing aggregates. The results showed that there is a priority order of these different parameters on the influence of the resistance to rutting. This highlights a competition between the properties of aggregate and type of granular skeleton. Indeed, for the same type of aggregate, asphalt binder type first impacts resistance to rutting of the HMA followed by aggregate gradation, volumetric properties of the mix and finally by the angularity of the aggregates. However, this order cannot be fixed and can depend of the intensity of each parameter.
Rutting generally refers to permanent deformation phenomena of the transverse profile of the roadway, which appear and grow as a result of traffic [1] [2]. The impact on the aggregate resistance to rutting of asphalt mixtures is explained by the material properties of formulations and the repeat of the traffic loads (accumulation phenomenon of the permanent deformation) [3] [4]. The properties of the mix design materials are specified for the bitumen by rheological tests (DSR) [5] or empirical test (Penetration test). Vanelstraete and Francken [6] showed that the permanent deformation measured by dynamic triaxial creep tests for a given bituminous mixture decreases with the rigidity of the bituminous binder used. Grimaux and Hiernaux [7] showed too that the resistance to rutting equipment of Road and Bridge laboratory Material (RBLM), generally increases in the presence of an increase in the hardness of the binder. A significant share of responsibility is granted to aggregate properties as angularity, percentage of fine particle and Nominal Maximum Aggregate Size (NMAS). Since aggregates make up entre 80% and 90% of the total volume or 94% to 95% of the mass of HMA, the quality of the aggregate significantly influences pavement performance [8]. Indeed, increased angularity causes an increase in rutting. On the other hand, another parameter to an important influence on the resistance to rutting of asphalt mixtures is aggregate gradation. However, for the same NMAS may have infinity of aggregate gradation, and for the same skeleton more value of angularity can be observed. This gives quite contrasting results from one study to another. El-Mamlouk and Basyouny [9] claimed that the coarse-graded HMA with great NMAS is more resistant to permanent deformation than fine-graded asphalt mixture. Stakston and Bahia [10] have shown that the resistance to rutting of asphalt mixtures largely depended on the aggregate gradation. Cross and Brown ( [11] ) on the other hand found that it’s angularity of fine aggregates that have a significant influence on the resistance to rutting and not the aggregate gradation. Manal and Attia [12] claimed that rutting resistance of asphalt paving mixes is affected by the type of aggregate and type of gradation. The diversity of results implies the existence of an interaction between the following parameters: binder stiffness, type of aggregate gradation, intrinsic and manufactured properties and volumetric properties of HMA. Indeed all the conclusions listed above are valid only if apart from the properties of mixtures considered in the comparison of performance between mixtures, all other remaining properties are constant. This is rarely the case between two bituminous mixtures. In this article a first approach to this interaction will be sought through the measurement of the resistance to rutting of bituminous mixtures with eight HMA manufactured with three classes of granularity granular skeletons [5]. These asphalt mixtures are manufactured with two types of aggregates (basalt and quartzite) and two types of asphalt binder (PG76-16 and PG 70-16), having substantially the same zeta potential and different flattening coefficients different fraction 8/16.