The present study addresses the thermal behaviour of a modified pavement structure to prevent icing at its surface in adverse winter time conditions or overheating in hot summer conditions. First a multi-physic model based on finite elements method was built to predict the evolution of the surface temperature. 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. Finally conclusion and perspectives are proposed.

Damage detection and localization in civil or mechanical structures is a subject of active development and research. A few vibration-based methods have been developed so far, requiring, for example, modal parameter estimates in the reference and damaged states of the investigated structure, and for localization

The mobility during winter season in France mainly relies on the use of de-icers, with an amount ranging from two hundreds thousands tons up to two millions tons for the roads only. Besides the economic impact, there are many concerns on their environmental and infrastructure, both on roads and on airports. In such context and in the framework of the R5G (5th Generation Road) project driven by IFSTTAR, investigations were carried out on the way to modify the infrastructure to maintain pavement surface at a temperature above water freezing point. Two distinct approaches, that can could be combined, were selected. The first one consisted in having a heated fluid circulating in a porous layer within an asphalt concrete pavement sample. The second one specifically relied on the use of paraffin phase change materials (PCM) in cement concrete pavement ones. Experiments on enhanced pavement samples were conducted in a climatic chamber to simulate winter conditions for several continuous days, including wind and precipitations, and monitored by infrared thermography. Studies concerning the first approach consisted in identifying the temperature range of the fluid to maintain asphalt concrete surface freezing-free. Both experimental and numerical approaches were conducted showing the importance of the role of the hydraulic conductivity of the porous layer. The analysis of infrared images indicated a surface temperature above freezing excepted in one situation, for which cold air convection and precipitations were combined at pavement surface. A temperature gradient along the surface was also observed. A good agreement was found between numerical and experimental results. To moderate the effect of precipitation, several PCM insertions were chosen and inserted at different depths, with various volumes and packaging (liquid, or powder of encapsulated liquid paraffin). At this stage of the study, rather mixed results were obtained. Delay in the surface ice formation was not conclusive, probably due to deeper location and an unsufficient amount of PCM used. Further investigation to carry out by coupling numerical and experimental approaches would help in refining the use of PCM for this application. The proposed paper will address the presentation of infrared monitoring developed during these studies.

We present in this paper the concept of solar hybrid road and focus on the thermal performances of such system. Main differences between these multi-layer structures with traditional road structures come from the pavement surface, which can be opaque or semi-transparent and the porous sub-layer, submitted to fluid flow. These structures aim at collecting solar energy during the summer season, what helps also to prevent from a too high temperature and urban heat island effect. A finite element model is presented to couple thermal diffusion, hydraulic convection and radiative transfer. This numerical model allows to compute the temperature field for different weather conditions and also to evaluate the thermal performances of the system. Annual simulations are performed and a comparison between two surface layer solutions for different locations and climates is presented and discussed.