Mix design of bituminous materials including reclaimed asphalt pavement

Reclaimed asphalt, obtained by milling of asphalt road layers can be re-used at once or stored. In the case of storage, an heterogeneity issue may occur when several types of materials, with different origins are mixed. At the scale of a storage zone or a stock pile, composition and properties of the reclaimed asphalts will be different, including variations of the final material properties, constraints for the stock manager, and the necessary adaptation of the manufacturing process. The reclaimed asphalt heterogeneity issue and the specific manufacturing process used in drum mixer asphalt plants have to be taken into account in ordre to optimize the laboratory mix design study as well as the physical, chemical and environmental criteria set in European legislation. The objective of this research work is to estimate the RAP heterogeneity in a material stockpile, as well as to improve the laboratory mixing procedure in order to better reproduce in laboratory the specific manufacturing process which can be found in drum mixer asphalt plants for these materials. The most relevant parameters are identified and a parametric study is carried out to estimate their level of influence on the behavior of the final bituminous material