CHARACTERIZATION OF SOME IRAQI ASPHALTS I. NUMBER AVERAGE MOLECULAR WEIGHT INVESTIGATION OF DORA AND QAIYARAH ASPHALTS

Abstract
The number average molecular weight (Mn¯) of two Iraqi asphalts has been studied before end after thermal treatment using vapour pressure osmometery. Changes in Mn¯ values after thermal aging were compared with the changes in their physical and mechanical properties. Toluene, benzene, cyclohexane, tetrahydrofuran and carbon tetrachloride were used to fractionate the asphalts The Mn¯ of each fraction was determined before and after aging.