Aim of Asphalt Recycling

The general aim of asphalt recycling is to rehabilitate a worn asphalt surfaced pavement, by returning the mix to an "as new" binder quality and particle size distribution, in a cost-effective and environmentally sympathetic manner.

Asphalt recycling is both:

• a rehabilitation or maintenance treatment
• a means of conserving energy and road making material resources.

The selection of asphalt recycling as an appropriate rehabilitation treatment should involve a life cycle costing analysis.

Asphalt recycling can only correct the asphalt layer. The underlying pavement must be sound and likely to remain so for the life of the treatment. This is particularly the case with high percentage RAP or HIPAR mixes, where stiffening of the mix is likely to occur and lead to fatigue cracking in the recycled mix.

The recycling of asphalt has particular significance in urban situations where it is necessary to maintain fixed levels due to kerb, gutter and utility fixtures.

Asphalt recycling may be viewed as part of the wider issue of Ecologically Sustainable Development (ESD), which embodies the more effective use of (road-making material) resources.

ESD decisions in relation to roads are complex and require a longer term and wider view of events than is normally applied to individual projects.

In this context, clearly virtually all road materials can be recycled in one way or another. Asphalt may be recycled and reused:

• in the same pavement
• in another pavement
• for purposes other than road pavement maintenance and construction.

Asphalt recycling has the environmental benefits of:

• reducing the demand for scarce road making materials
• reducing the demand for landfill areas
• (for on-site recycling) reducing the traffic loading on the road network and reducing delays to motorists during construction work
• reducing the energy demands of the pavement rehabilitation process.