Stripping phenomenon in thick pavement top layers
Résumé
Most of the heavily trafficked French roads, like thick pavement structures, are now thirty or forty years old. Since construction, top layers only, have undergone one or more repair operations. Traditional rehabilitation works consist in overlaying the old wearing course or in milling it before covering it with a new overlay. For a few years, unusual deteriorations in highway structures, like pothole series or top layer delamination, have appeared. These phenomena generally occur after winter and more precisely during rainy events. The purpose of this paper is to investigate three cases of degradations observed for both rehabilitation types. The mechanics of the action causing upper layer deteriorations has to do with freeze-thaw processes combined with humidity and traffic. Nevertheless, other causes can add further to pavement degradation long before any surface deteriorations appear. The presence of water near the surface, for instance, can explain some of the damages observed. The fatigue of the layers during hot weather periods can also be at the origin of damages, even though rutting is more traditionally expected as a consequence of fatigue. Deterioration processes are discussed and illustrated by results from a study conducted on the LCPC's circular test track facility revealing some fatigue phenomenon at the level of the first interface when the weather is hot, which, combined with traffic and rainy, wintry conditions,can weaken top layers and lead to their quick degradation.
Origine : Fichiers produits par l'(les) auteur(s)
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