Mechanistic-empirical mixture design for hot mix asphalt pavement recycling

Mixture design of six asphalt mixtures containing Reclaimed Asphalt Pavement (RAP) were evaluated by using a mechanistic-empirical approach. The testing methodology involved determination of the key mechanical properties and durability of wearing course and base course materials containing RAP at three different levels of addition (i.e. 10%, 30% and 50%), manufactured to a supplied specification, and the rheological properties of binder used in, and recovered from, these materials. In order to optimise both rutting and fatigue resistance, the recycled mixtures were manufactured by using 80/100 pen virgin bitumen (which is one grade softer than the 60/70 pen bitumen conventionally used for the respective parent asphalt materials), with or without added rejuvenating oil. This paper demonstrates that the asphalt mixtures containing RAP performed at least similar to, or better than, that of conventional asphalt materials.