Nasrin Oroujzadeh - Assistant Professor, Institute of Chemical Technology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
Hamid Sabbagh - Consultant of Iran Road Maintenance and Transportation Organization, #14, Dameshgh St., valiasrAve., Tehran, Iran

In this research, knowing about the impacts of crumb rubber, poly phosphoric acid and vestenamer on the behavior of bitumen, it was tried to improve the performance of PG58-22 bitumen by using these additives simultaneously. Five samples of modified bitumen were prepared using PG58-22, PPA, Vestenamer, and various CR percentages. The samples were classified according to the superpave performance grading system. We found that GTR/PPA modification improves the performance grade of bitumen at high, intermediate and low temperatures. This type of modification is significantly better than modification of bitumen only by use of CR or PPA. Modification reduces the risk of cracking at low temperatures and rutting at high temperatures. The degree of modification generally increases with CR content.

Crumb Rubber, PPA, Vestenamer, Modified bitumen, Performance grade