Adapting of Performance Grading System for Local Asphalt Cement

Abstract

The General Specifications for Roads and Bridges (SCRB) don't adopt the performance grading (PG) based system suggested by Superpave program to evaluate the currently used asphalt cements for paving works. The air temperature data used in this study covers approximately 20 years time period (1982-2002) for seven Iraqi cities (Kirkuk, Mosul , Rutba , Baghdad , Kut , Najaf , and Basrah) which represent climatically unique regions in Iraq. The currently used asphalt cements with penetration grades (40-50) and (60-70) were tested by both of conventional test methods and Superpave methods to determine the equivalent performance grade for each type of the penetration graded asphalt and to evaluate the capability for these two types of asphalt cement to satisfy the required performance of pavement for each region of country. The paper results indicate the following for the required PG asphalt binders: Region Performance Graded (PG) Asphalt Binder North governorates 70-16 Middle governorates 70-10 West governorates 64-10 South governorates 76-4 The Daurah asphalt cements with penetration grade (40-50) are equivalent to PG 70-16, PG70-10 and PG76-4 while asphalt with penetration grade (60-70) is equivalent to PG 64-10. The rotational viscosity , dynamic shear rheometer and creep stiffness versus penetration relationships have been developed to estimate the some Superpave asphalt binder tests based on penetration values.