ANR NANOROAD : Linking NANOstructure and macroscopic properties of bitumen to improve their recyclability and ageing : towards a sustainable development of ROAD materials

_{ANR NANOROAD (2023-2027)}

Project coordinator :

François Henn, L2C, Montpellier

Partners :

CEREMA, Aix-en-Provence (project coordinator)
ESTP, Cachan
TotalEnergie
Vinci Construction

Project goal :

*Fig.1 : AFM image at room temperature of bitumen, clearly showing microstructures on the surface in a honeycomb pattern.*

Bitumen is a complex viscoelastic hydrocarbon compound that is sensitive to temperature, pressure, radiation and oxidation.

As it ages on roads, its viscosity increases and its chemical composition changes significantly.

Observing, understanding and assessing the impact of ageing on the colloidal nanostructure of bitumen are the three key steps that could help stakeholders and industrial partners to better select their products with a view to sustainable development (eco-design) aimed at reducing the environmental impact of road construction.

*Fig.2 : TEM image of a microtome section of unaged bitumen, where nanostructures in sheets can be clearly distinguished.*

High-tech tools such as USAXS, SAXS, various electron microscopy methods and AFM (Fig. 1) are used to study bitumen at the micro and nanoscales.

The results obtained in this way are combined with those obtained using more traditional techniques (physicochemical characteristics and rheological behaviour of bitumen and mechanical properties of asphalt materials) used to characterize their macroscopic properties.

It is thus expected to be possible to directly characterize the bituminous matrix over a very wide range of scales, i.e. 0.2-1000 nm, and its evolution with: a) ageing, b) regeneration treatments, and c) the temperature corresponding to the fluid-viscoelastic transition state.