Abstract
Maintaining an efficient road network requires a regular servicing of existing roads as well as the construction of new ones. One of the most widely used techniques is that of hot-mix asphalt, which, like all industrial activities, is confronted with the requirements of sustainable development. To meet these requirements, the use of Reclaimed Asphalt Pavements (RAP), which are a new source of raw materials derived from the recycling of old roads, is an important practice in the manufacturing of recycled asphalt mixes.The development of such recycled asphalt mixes requires controlling their characteristics in order to obtain performance and durability levels comparable to that of a new asphalt. The higher the recycling rate, the more difficult it becomes to achieve this goal. One of the major factors influencing the durability of recycled asphalt mixes is the evolution of the bituminous binder, a viscoelastic material made up of the oxidized binder from the RAP and the filler binder.This thesis work, with a strong experimental focus, aims to understand the regenerating mechanisms of oxidized aged binders within recycled asphalt mixes while defining the long-term evolution of the physico-chemical and mechanical properties of these bituminous materials. It will therefore make it possible to qualify recycling agents to guarantee the durability of the recycled asphalt.This work will be carried out at two scales: the bituminous binder and the asphalt mix, according to a physico-chemical and mechanical approach. At the binder level, X-rays scattering, spectroscopic and calorimetric techniques will be used to study the colloidal structure of bitumens, including a qualification of the generic composition and state of aggregation of asphaltenes. The impact on the performances will be assessed through rheological measurements. At the asphalt mix scale, a mechanical qualification will be carried out in particular at low service temperatures, which are known to be critical for bituminous materials subject to the effects of ageing, climatic and road environments. At both scales, all the experiments will be conducted before and after application of an artificial ageing process for bituminous materials in the laboratory. This work will lead to a scientific qualification of the different families of regenerating products available on the market, predicting performance and durability.