USE OF CRUMB RUBBER AS A WAY TO IMPROVE PERFORMANCE GRADE FOR ASPHALT CEMENT

The purpose of this research is to study the performance grade of asphalt cement with scrap tire in form of crumb rubber (CR) as additive material. It also emphasizes on determining the optimum proportion of additive to be used in the mixing process. In this research, the materials used have been originally taken from the available sources in Iraq. One type of asphalt cement with penetration grade is equal to (40-50) from Al-Nasseryia refinery was used with one type of locally polymer is Crumb rubber with different particle sizes from scrap tires as asphalt modifier. The results showed that modified binders outperformed conventional asphalt cement in term of performance grade. It can be concluded from this research that the use of crumb rubber as additive material is the best alternative. Due to its domestic availability, crumb rubber is more suitable for road making in the scrap tire producing countries and to the fact that the utilized scrap tire as additives tend to improve viscosity and rheological and mechanical properties of asphalt cement and bringing greater service life expectancy. The suggested proportion of crumb rubber in blending with asphalt cement is 18 percent by total weight.