MSCA-COFUND-CLEAR-Doc - PhD Position #CD21-18 "Innovative pavement biobinder development and ageing resistance"

The Transportation Infrastructure construction sector is aware of its environmental footprint and is thus continuously moving towards more environmentally friendly technologies. Concerning asphaltic pavement, it is necessary to find cost effective solutions for a circular post-fossil fuel society that could promote the wide-spread use of alternative bitumen from renewable raw materials that do not interfere with the food industry, as well as polymer as main ingredients of asphalt mixtures. This could lead towards energy efficient long-lasting road pavement built with the lowest amount possible of non-recycled materials and thus, minimize the footprint of a road infrastructure significantly.

In this context, the PhD project proposes to explore some routes related to the organic matrix which could be used to bind mineral aggregate skeleton (alternative to bituminous mix). It is proposed to work first on finding new solutions to replace bitumen, secondly to work on smarter accelerated ageing procedures for innovative organic pavement materials.

The project is based on a original European partnership composed of University Gustave Eiffel, University of Palermo, Technical University of Wien and Eiffage. The project deals with a concrete problematic in line with nowadays environmental concerns.

The first part will be dedicated to alternative biobinder development. This work will profit from existing solutions which are currently studied by partners such as Biophalt whoch has been developed by Eiffage or more recent project using tire waste associated with Vegetal oil. Moreover, these existing solutions will be used as inspirative concepts to find new promising biomass. They will be chosen according to a literature review and local agriculture residue availability.

Scientific challenges of this first part will be to solve how to chemically transform biomass to produce a sticky viscous material adaptable to asphalt mix production and use. Produced materials will be mainly assess using rheologic properies.

The second part will be dedicated to the ageing mechanism of recently developed binders. Trial sites have been already done with Biophalt vegetal binder and tire waste associated with vegetale oil. They will be served at reference for field ageing. Main works will consist in developing lab accelerated ageing procedures to assess the ageing kinetic of material coming from biomass and tyre residues in relevant environments (e.g. continental or oceanic or mountain climates). In order to undertake fundamental investigation in the aging process, the materials will be aged by varying factors, such as temperature, reactive oxygen species (ROS, e.g. nitrogen oxide and ozone), UV exposure, and also using specialized equipment simulating aggressive environment such as the marine context with high concentration of moisture and salt (University of Palermo) as well as state-of-the-art facilities at TU Wien. TU Wien has been studying ageing of asphaltic materials, developing and improving lab ageing simulation in the past 12 years. With the Viennese Binder Ageing (VBA) device, a highly flexible and sophisticated approach to simulate field ageing in the lab is available. With the use of VBA, binder materials can be aged while varying temperature, concentration of ROS, UV-VIS radiation and moisture. Thus, the simulation in the lab can be adapted to the observed field ageing in the trial sites.

Scientific challenges of this second part will be to determine the main biobinder molecular changes during ageing and the consequences on the mechanical properties (in order to be able to reproduce ageing mechanisms in lab).