In this study four types of polymers (alpha cellulose, saw dust, carboxyl methyl cellulose and natural rubber latex) are employed to improve the properties of Iraqi asphalt (40/50), produced in al-Daura refinery. The additives were selected for their availability and low cost and enhance the quality of asphalt specification through the process of asphalt concrete evaluation before and after additions, the process of mixing has been at a temperature 160°C, mixing speed at 200 RPM during 90 min, the operating conditions have been chosen to conform to the operations of mixing and processing of asphalt concrete published by the AASHTO. Modified asphalt samples exhibit performance and improvement of physical through;
•The penetration decreased from 40 to 20.7mm, the softening point increase from 48.8 to 70.2C, viscosity increase from 450 to 3650 Cst, PI to 0.92 at (5%NRL+8% AC);
• The toughness was significantly enhanced from 0.9 to 9.6 K.N at (5%NRL+4% CMC);
•The tenacity was significantly enhanced from 0.3 to 8.5 K.N at (5%NRL+8% CMC);
• The PVN to 0.96 at (5%NRL+6% AC) ;
•For most of the prepared samples the ductility was improved to more than 100cm. The mechanical properties were tested for samples that showed the best physical properties by Marshall Method after determined the optimum binder content was (4.9%), The results indicated that improved the stability from 13.8 to 15.79 at(5%NRL+ 4% AC), flow from 2.7 to 2.1 and stiffness from 5.13 to 6.47at (5%NRL+6% AC), as well as improved density, air voids, V.F.A and V.M.A values, and this inferred to improved resistance to the rutting at high temperature and to cracks at low temperature which is considered as major pavement distresses of Iraqi asphalt.