7. Pathological phenomena and mechanical models

The degradation of pavements is a natural process of plastic behaviour of the constituent materials and the soil, under the effects of :

• traffic and pavement operation, leading to material fatigue, cracking, ravelling and rutting;

• natural ageing, which changes the mechanical properties of materials, mainly hardening bitumen and making it more brittle;

• climatic conditions, with high temperatures producing rutting under traffic, low temperatures producing thermal differential shrinkage cracking, and rain or frost producing stripping.

Pavement pathologies can only be considered in terms of the premature appearance of deterioration, in relation to the initial dimensioning and the objectives set during the design and construction of the structure....