Proposals for modification of Iranian bitumen to meet the climatic requirements of Iran

In this research, bitumen from seven Iranian bitumen production plants were tested and characterized according to the Superpave performance grading (PG) system. The study compared the results of this classification with the 13 performance grade binders required for specific climatic zones in Iran. A set of modifiers, as well as laboratory air blowing, were used to generate the required PG binders. The modifiers used were crumb rubber, gilsonite, polyphosphoric acid, and styrene–butadiene–styrene (SBS). It was found that the variety of available binders is not adequate to fully cover the required PGs.