Abstract
In Kingdom of Saudi Arabia ( KSA) number of vehicles increased dramatically with an annual growth rate of 5 to 6%. This increase in number of vehicles lead to heavy traffic loads which lead to structural problems for the layer of the pavement. There has been a huge amount of investment in road infrastructure. Accordingly, road network is facing different problems in different aspects such as bituminous materials, loading and design method. A detailed experimentation has been carried out to investigate and evaluate the binder, aggregate and mixture composition, air void, materials characterization and improving pavement performance by using five different types of polymers with different concentrations. Several mixes were tested using Marshal tests. Dynamic shear Rheometer used to characterize bitumen and modified bitumen. Results show that use of plastomer polymers types (e.g. Polybilt-101, EE2) to modify the asphalt binder by improving their physical and rheological properties to meet the performance requirements is effective. It is possible to use different types of polymers (LDPE and HDPE) and different percentage of polymer concentration to achieve the performance requirements (e.g. PG 70 can be achieved by using 3% of EE2 or 4% of Polybilt).. It can concluded that the asphalt 60/70 pen grade which is used today in eastern province, KSA, meets the performance requirements to resist the main distress of flexible pavement. The asphalt binder behavior affects the performance of asphaltic concrete mixes. However, there are several important characteristics of asphalt binder (e.g. the adhesion of asphalt binder to aggregate) should be evaluated besides modification of asphalt binders.

Key words: Asphalt; asphalt mixture; polymers; modified asphalt