Field Sampling and Laboratory Preparation of Hot Mix Asphalt (HMA) With Admixture: Insights From Erbil Roads

Asphalt cement, often referred to as asphalt or bitumen, is a fundamental material used in the production of hot mix asphalt (HMA) for road pavements. Historically, asphalt was combined directly with other materials to create conventional HMA without any form of modification. Three percentages (3%, 5%, and 7%) by weight from both of them were mixed with asphalt type 40/50 and 50/60 penetration grade obtained from Lanaz/Erbil refinery. Two types of aggregate and the sample type of asphalt, adding cement, silica fume, and polymer, were used to examine how they affect HMA and compare with Erbil temperature. Admixtures such as cement, silica fume, and polymer, used to modify HMA, significantly improve bitumen properties, reducing penetration by an average of 10%. Experimental studies have demonstrated that crushed natural aggregates, when used in high‐temperature asphalt mixtures, exhibit a higher specific bulk density and superior stability compared to natural aggregates. Results also indicate that the optimum amounts are 7% by weight for both cement and polymer materials and 5% for silica fume.