Development of a laboratory bituminous mixtures ageing protocol

The RILEM TC-ATB-TG5, in charge of recycling of bituminous materials has decided to develop a laboratory procedure with the aim of reproducing the ageing of bituminous materials until the end of their service life (milled product). This procedure will help to assess the recyclability of mixtures and will allow Recycled Asphalt Pavement (RAP) production in the laboratory in a realistic way. The ageing of bituminous materials is mainly linked to the ageing of the binder and is normally separated into short and long-term ageing : The short-term ageing simulating ageing caused by the manufacture of the material in the mixing plant, transport and paving, especially the necessity to increase the binder temperature up to 160-190°C according to the type of binder and material to be manufactured. The long-term ageing simulating the influence of the climatic conditions and traffic loading on ageing during service life. In the framework of an LCPC fatigue carousel experiment, a bituminous material with a 35/50 pure bitumen was laid in January 2008. Loose mix and components (aggregates, bitumen) of the mix have been sampled to carry out a laboratory ageing round robin test, organised between the labs of the RILEM group. Also, on the fatigue carousel, coring will be carried out at several intervals to follow the evolution of the material. In this paper, a state of the art regarding the existing methodologies for the laboratory ageing of bituminous materials is presented as well as the round Robin test, including the tested ageing procedures and the tests chosen to validate these procedures according to the field site data. The first results are discussed with the focus on distribution analysis