Effect of global warming and new equivalent temperature zoning maps for asphalt pavement design in Morocco

Abstract

Global warming has a negative impact on society and the environment. Pavements may also be affected. Indeed, for the design of bituminous pavements according to the French rational method, the equivalent temperature (θE) should be used. θE is a constant that takes into account the actual change in pavement temperature. The objective of this study is to evaluate numerically the effects of global warming on bituminous pavements and on θE and to propose new zoning maps of θE suitable for the current climate and its variation by region. To address this issue, θE was calculated for 25 cities for four different bituminous structures and using a Python code developed for this study. Then, the θE values were geographically interpolated on the map of Morocco. To evaluate the effects of global warming, θE was plotted as a function of time for three cities. Finally, the effect of bitumen choice on its resistance to global warming was studied by comparing rutting depths and temperature profiles in bituminous layers made by those bitumen types. The bitumen types compared were pure 35/50 and 50/70 bitumens and a polymer modified bitumen. According to the calculations, the estimated θE varies between 23.9 and 30.9 °C and is higher in the south of Morocco. In addition, θE follows the same upward trend as the earth temperature. The effect of global warming can be reduced by an intelligent management of the traffic and by using adequate materials such as polymer modified bitumens. The type of bitumen chosen among those studied does not influence the asphalt temperature profile.