Sustainable reuse of highway materials in hot and cold bituminous mixtures

In the last few years there has been growing concern about the increasing d emand placed upon finite resources. Many organizations and types of industr y now encourage the practice of sustainability. With the introduction of th e landfill tax, aggregate lax and the increasing cost of bitumen, highway a uthorities must now consider other methods to achieve better value for mone y. In highway engineering, reduction in use of aggregate and bitumen resour ces can be achieved by better understanding of pavement design and choice o f materials used. It may also be facilitated by the reuse of bituminous mat erials that have been removed from the pavement structure as part of a main tenance programme. This is termed reclaimed asphalt pavement (RAP) and is p ermitted in hot-mix asphalt in accordance with the Specification of Highway Works Clause 902. A combination of these two approaches will enable the ma ximum reuse of this type of material without urning the highway into what m ay he termed a waste disposal location. This paper shows how clients such a s local highway authorities are maximizing reuse opportunities. It also giv es an example of how suppliers are now collaborating with academic institut ions to develop new technologies to solve the client's problem. Two experim ental trial road sections are detailed which were designed and constructed to evaluate the use of RAP in a hot and a cold bituminous mixture. This as enabled the authors to quantify the benefit of using recycled materials and technologies.