Section: New Results

Smarts roads and R5G

Energy exchange modelization and infrared monitoring for hybrid pavement structure

Participants : Nicolas Le Touz, Thibaud Toullier, Jean Dumoulin.

In those studies, we evaluate by numerical modelling the energy inputs that could occur in a hybrid pavement structure with a semi-transparent or opaque wearing course bonded to a porous base layer, the seat of a heat transfer fluid circulation. The digital studies conducted propose a coupled resolution of various thermal phenomena: diffusion/convection in the case of an opaque surface drainage pavement, and diffusion/convection/radiation for a pavement with a semi-transparent surface. Coupled equation systems are solved numerically using the finite element method. This model was developed directly on a Matlab kernel. In a second time, laboratory experiments on small specimen were carried out and the surface temperature was monitored by infrared thermography. Results obtained are analyzed and performances of the numerical model for real scale outdoor application are discussed .[35], [34]

Phase change materials characterization

Participant : Jean Dumoulin.

In a costs reduction and comfort requirements context, the use of phase change materials (PCM) is a sustainable and economical answer. For transportation infrastructures and winter maintenance, they avoid ice occurrence or snow accumulation. Their characteristics, and more specifically, the solid to liquid phase transition temperature and enthalpy, are usually obtained through DSC. Raman spectroscopy can bring answers and information on their microstructures. The liquid to solid phase change was investigated on three PCM, a paraffin, formic acid and diluted formic acid. A comparison made on freezing temperature obtained through DSC, Raman spectroscopy associated with chemiometrics indicated a consistency between the methods. Raman spectroscopy coupled with multivariate data analysis allowed the identification of an additional specificity in the freezing process of the paraffin. All methods provided results consistent between each other, although some differences between literature and experimental freezing temperatures of the considered PCM were observed in all cases. [20], [53]