Selection and verification of performance grading for asphalt binders produced in Jordan

Selection of proper binder is one of the most important factors considered in mixture design. Three different asphalt grading systems are normally used; they are penetration grading system, viscosity grading system and performance grading (PG) systems. PG system is a method of measuring asphalt binder performance; it was originally developed during strategic highway research program in the early 1990s in order to accurately and fully characterise asphalt binders for use in hot mix asphalt pavements. PG system is based on the idea that the properties of an asphalt binder should be related to the conditions under which it is being used. This involves expected climatic conditions, pavement temperature as well as ageing conditions. Performance-graded asphalt binders are selected to meet expected climatic conditions as well as traffic speed and load conditions. Therefore, the PG system uses a common set of tests to measure physical properties of the binder which can be directly related to field performance of the pavement at its service temperatures. In order to adopt the Superpave system in Jordan, it is essential to develop climatic zones for Jordan and to select the proper performance-graded binder to be used in different regions in Jordan. Selection of performance-graded binder is based mainly on the air temperature of the desired location. Several models were used to calculate the pavement temperature. Different reliability levels were used in developing the climatic zones in Jordan. Finally, Jordan was divided into different zones and specific binder type to be used there. On the basis of analysis, binder grade having designation PG 64-10 can be used in most parts of Jordan. The only source for asphalt binders used in the construction of flexible pavements for Jordan's highways and streets is the Jordan Petroleum Refinery (JPR). Typically, the JPR produces two main types of original asphalt binders; these are 60/70 penetration grade asphalt binder and 85/100 penetration grade asphalt binder. On the basis of laboratory test and according to the Superpave asphalt binder classification system, the 60/70 penetration grade asphalt binder can be classified as PG 64-16 and the 85/100 penetration grade asphalt binder as PG 58-16.