Selection of pavement materials takes very important role in pavement design procedure. The understanding of pavement structure behavior under cyclic loading is necessary in order to assure its serviceability during a predicted structure life. Unbound granular material layers in pavement structure represent a base for upper construction and their compaction and deformational behavior under cyclic loading have significant impact on the bearing capacity of upper layers and overall pavement construction. Unbound granular materials show complex behavior under cyclic loads with gradual accumulation of permanent deformation. Accumulation of a large number of small permanent deformation in unbound granular material usually affects on behavior of the sub-base layer and larger irreversible deformations in the upper layers of the pavement structure. Several analytical models have been developed to describe the development of the permanent deformations and behavior of unbound granular materials affected by these deformations. Recent studies and analyses are oriented on laboratory testing of different types of unbound materials under triaxial loading. These studies aim at developing analytical models which are more accurate in predicting deformation behavi

unbound granular material; pavement construction; permanent deformation; analytical models; triaxial loading