European project RE-ROAD: round robin test on extraction and recovery methods for Reclaimed Asphalts with Polymer modified Bitumens

The recycling of Reclaimed Asphalt (RA) in new hot-mix asphalt (HMA) is a common practice throughout Europe. However, Reclaimed Asphalts (RA) are complex materials and the use of significant proportions of RA involves a more accurate control of their characteristics. This is an essential step for asphalt mix design and a key factor to obtain good performances. At this time there is clearly a lack of knowledge and adequate test methods to analyse RA with Polymer modified Bitumens (PmBs). The present European test methods for extraction and recovery of binder in RA is suitable for RA with pure binders but give only indicative guidelines for RA containing PmB. To develop techniques for increasing the recycling rates of RA especially in surface asphalt mixes, the binder characterisation test methods are analysed and optimised during European research project Re-road. This contribution presents the results of a round robin test on: * soluble binder content using different normalized extraction methods and solvents according to EN 12697-1 * characteristics of recovered PmB (namely penetration, softening point, oxidation degree) using different normalized recovery methods and solvents according to EN 12697-3 (rotary evaporator) Six laboratories participated in the round robin test, in which three different bituminous materials have been analysed: one Stone Mastic Asphalt including 15% of RA and two other RA with physical and cross-linked elastomer modified bitumens. The round robin test has contributed to the evaluation of present methods and their (dis)advantages for studying RA containing Polymer modified Bitumen (PmB), the ultimate aims being to improve the characterization of RA containing PmB.