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Road networks play a vital role in the development of country's economy. It is necessary to develop new technologies to improve the performance and safety of the roads. Added to that, it is necessary to enhance the evolution of the roadways over time in terms of maintaining its surface while respecting the challenges of sustainable development. Microsurfacing is one of the techniques used to satisfy these challenges. However, there is very little information on the evolution and behavior of the product on short and long term, and there is no information on the use of recycled materials in the latter. In this context, this study aims to study and improve the performance of mixtures of microsurfacing with recycled materials. After the development of an adapted accelerated aging method on Microsurfacing, materials were prepared in lab with reclaimed asphalt pavement (RAP) and with recycled asphalt shingles. It was shown that it's possible to prepare microsurfacing with 100% RAP while respecting all International Slurry Surfacing Association (ISSA) standards. The results have shown that the filler's characteristics have a big impact on the rutting resistance of those mixes. Procedures were developed during this project to measure the water sensitivity of the mixtures and their behavior over time.

The French national project MURE, a collaborative research and development programme, started in March 2014. Two main issues are addressed: coupling of recycling and warm-mix asphalt technique and multi-recycling of bituminous mixtures. It gathers the national road federation, academic laboratories, road contractors and project contracting officials. The objective of the first working group (WG1) of MURE is to validate an accelerated ageing process for bituminous mixtures as well as on site than in laboratory. To achieve this goal, it is first necessary to characterize the ageing using a reliable and reproducible method valid for laboratory and plant-made mixtures. Many studies from the literature showed the efficiency of FTIR spectroscopy for ageing identification. In particular, carbonyl and sulfoxide groups found in binders are appropriate ageing markers. Meanwhile, no common FTIR protocol does exist at present. The first step of the experimental work performed by the WG1 was to compare seven FTIR methods, differing from sample preparation and approaches for calculating spectroscopic indexes. One given bitumen was aged eight times successively by RTFOT method (75 min-163 °C). Two IR spectrum acquisition modes were tested: attenuated total reflectance (ATR) and transmission (spreading of bitumen on an IR transparent plate and bitumen dissolution in a solvent). The second step of the study was to verify the repeatability of FTIR tests on neat and aged bitumen according to sample preparation and calculation methods. The results allow confirming the relevance of FTIR spectroscopy for qualifying bitumen ageing. A single methodology and a common tool for harmonizing the calculation of indexes are proposed. The whole procedure can be used to follow the ageing properties on site at short and long times.

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