Rut Resistance Behavior of Pavement Structures Combined by the Different Asphalt Mixtures

In this paper rut resistance behavior of pavement structures combined by the different asphalt mixtures is presented. Nine types of Hot Mix Asphalt (HMA) and ten types of their different combinations are experienced with China´s wheel tracking tester in this study. They are composed of three types of aggregate gradation including a coarse, a middle and a fine gradation of norminal aggregate size of respectively 26.5mm, 19mm and 13.2mm, and three types of asphalt binders including a Conventional Bitumen, a Modified Bitumen and a Super-Viscous Modified Bitumen. Experimental results showed that the rut resistance behavior of all double-deck asphalt concrete whether it is made up of different HMA or the same, is considerably poorer than that of relative monolayer asphalt concrete. There is no exception even to a combination of Super-modified bitumen with coarse aggregate gradation. The results also indicated that if the Conventional Bitumen binder is substituted by the Modified Bitumen or Super-Viscous Modified Bitumen binder in the down-layer of double-deck asphalt concrete when the HMA of up-layer of double-deck asphalt concrete structure is the same type, rut resistance property has been improved but not remarkably. Therefore in China´s Specifications for setting the dynamic stability of monolayer asphalt concrete to meet the requirement of 800(times/mm) as a criterion of controlling rut of multi-layer asphalt concrete is unreasonable.