|dc.description.abstract||Asphalt pavement is the major pavement type worldwide. Today, over 90% highways are paved with asphalt concrete. Like other pavement types, asphalt pavement suffers from certain types of damage, which call for maintenance. Billions of dollars are spent on the maintenance of asphalt pavement each year.
To reduce the maintenance cost, satisfactory pavement design that addresses the mechanical and chemical properties of asphalt pavement, is necessary. In pavement design, two of the factors affecting pavement durability are the absorption of asphalt into porous aggregates and the hardening of asphalt due to oxidation. Asphalt absorption reduces the effective binder content in the pavement. Meanwhile, the oxidative hardening of asphalt will eventually lead to pavement fatigue cracking.
This work focused on the properties of flexible pavement materials, especially asphalt absorption process and oxidation kinetics. The objectives were to evaluate and improve the current method of absorption measurement, and to study the oxidation kinetics of warm mix asphalt (a new pavement technology widely used). To achieve these objectives, studies were designed and conducted.
Asphalt absorption in porous materials was systematically studied. A new method for asphalt absorption measurement, using a density gradient column, was developed to measure asphalt absorption in single aggregate particles at a higher precision level. Experimental results showed that asphalt absorption correlated very well with the void volume in asphalt, regardless of the aggregate type. Moreover, the effect of contact time on asphalt absorption was studied. Finally, the asphalt absorption of warm mix materials from loose mix samples was measured using a density gradient column.
Additionally, the oxidation kinetics of warm mix asphalt was investigated. Oxidation kinetics parameters were estimated and used in a pavement aging simulation. Insignificant differences between the warm mix asphalts and the base binder control were found. These oxidation kinetics results provided a better understanding of the pavement performance of warm mix asphalt.||