ABSTRACT
Bitumen is a ‘hydrocarbon product produced from the refining of crude oil’ that is ‘a thermoplastic, viscoelastic liquid that behaves as glass-like solid at low temperatures and/or during short loading times and as a viscous fluid at high temperatures and/or during short loading’ (Hunter et al., 2015), making it one of the most complex construction materials. When it is combined into asphalt, which is a ‘surfacing material consisting of bitumen, mineral aggregates and fillers and may contain other additives’ (Hunter et al., 2015) for which the aggregates can have a variety of shapes, gradings and compositions, that asphalt becomes an even more complex material that has been, and is being, used successfully on roads, airfields and other paved areas. However, the properties asked of asphalt pavements (the number of which seems to be continually increasing with time) differ both for different layers within the pavement and for different circumstances and, therefore, require different asphalt mixtures.
