Characterization of Bituminous Mixtures for Numerical Modeling of Permanent Deformations

Because of recent increase in traffic intensity and axle loads, the relevance of rutting due to permanent deformation of the bituminous layers has increased on road pavements. In fact, recent pavement performance studies indicate that rutting in the bituminous layers is a major deterioration mechanism in flexible pavements. Most of the models used for pavement design do not take this mechanism explicitly into account. One of the reasons for that is the difficulty to determine the parameters that describe the materials behaviour for use in advanced models. A simple laboratory test and interpretation methodology is necessary to evaluate its permanent deformation behaviour. Ideally, it should be able to simulate “in situ” conditions and the test specimen should be representative of the bituminous materials applied on the field. However, more “realistic” test methods involve more complex and expensive equipment together with high levels of technical expertise. This paper deals with the use of uniaxial cyclic compression tests to evaluate the permanent deformation of bituminous mixtures. The results derived from these tests can be used for the prediction of permanent deformation in bituminous pavements assuming that the bituminous mixtures have viscoelastic behaviour.