An overview of the use of nanoclay modified bitumen in asphalt mixtures for enhanced flexible pavement performances

Bitumens are complex materials, produced mainly from crude oil as a by-product of petroleum refineries, but may also be obtained from bio-oils or solid hydrocarbons. Bitumen specifications have become stringent, mainly because they are used as binders in asphalt mixtures that have to offer good resistance to weather and traffic erosion. There are many different types of additives that can be used to improve bitumen properties and, consequently, asphalt mixtures performance. Nanoclays are one of the newest additives being used in paving grade bitumens to increase their in-service performance. This paper covers the main aspects of asphalt mixtures with nanoclays, including constituent materials, mix design and mechanical performance issues, as well as technical specifications.