Melting snow or de-icing with a hydronic system may be employed for some critical roads sections particulary sensitive to winter conditions (turns zone, highways upslope or downslope, bridges, etc.) in order to avoid dangerous driving conditions caused by snow or ice. This article presents a hydronic heating system that circulates a heated fluid through a bonding porous asphalt layer, to prevent ice formation at the road surface. In this article, we study the heat exchange between fluid and road. Firstly a 2D thermo-hydraulic model is developed in order to determinate the temperature field in the pavement structure when the fluid circulates in the porous bonding layer. Secondly, the sensibility of the temperature distribution at the road surface is studied to identify the most relevant model parameters. Finally, the evolution of the minimum temperature of the injected fluid with different flow rate is determined in order to keep positive the road surface temperature at any point for given meteorological data.