ABSTRACT
Durability is the ability to survive and continue to give an acceptable performance. This chapter talks about ageing of bitumen during mixing, storage, transportation, application and service. The ageing or hardening of bitumen is an inevitable result of exposure of bitumen to the atmosphere. The rate of hardening will depend on the conditions and the nature of the bitumen. There are two main processes that occur: oxidation and loss of volatiles. Thus, there is an increase in the polar, high-molecular-weight fraction at the expense of the lower-molecular-weight components. Tests related to ageing of bitumen can be broadly divided into tests performed on neat bitumen and tests performed on asphalt mixtures. Tests related to ageing of bitumen can be broadly divided into tests performed on neat bitumen and tests performed on asphalt mixtures. In the oxidation process, oxygen molecules from the air combine with the aromatics and resins to form asphaltenes.
