Rutting analysis of modified asphalt concrete pavements

The aim of this research was to model rutting of modified stone matrix asphalt concrete pavements. Four mixes were investigated, including two modified with different percentages of styrene–butadiene–styrene (4 and 6%), one modified with cellulose fibres and one unmodified mix. Dynamic creep tests were performed on specimens of each mix to obtain material parameters of the creep power law used for rutting modelling purposes. For each mix, a model was developed and then a finite-element method was used to estimate the rut depth of a pavement structure by incorporating realistic material properties for the base course, subbase course and subgrade beneath the asphalt concrete pavement surface. Results of applying static and repeated loads on modelled pavement show that the rut depth of static loading is greater than a repeated one. Moreover, a pavement made from asphalt concrete modified with 6% styrene–butadiene–styrene would have the least rut depth followed by the 4% mix, the unmodified mix and the cellulose fibre mix, respectively.