You probably don't give it a second thought as you drive to work in your car. But when you are stuck staring at the back end of a bus in a traffic jam, your eyes might just wander onto the road. It might seem greyish but that asphalt you are looking at is about to get a little greener thanks to a European Commission funded project. Asphalt recycling is getting an upgrade.
© Fotolia, 2012
Europe has about 5.5 million km of roads and most (90%) are made of asphalt. We all know a bad road when we drive on one so this is why billions of Euros are spent each year digging them up and replacing them.
Both industry and governments recognise the potential environmental costs of road building. While traffic pollution often grabs the headlines, extracting new aggregate and disposing of old asphalt from road building can also cause significant environmental issues. It will not escape your attention that, while asphalt is nearly 100% recyclable, routine use of recycled asphalt in road building projects can be as little as 10% in some European countries.
Costs, lack of awareness, performance worries or even political unwillingness means asphalt is more likely to end up in landfill in some countries than recycled into new road. It is often simply cheaper to extract new aggregate and bituminous binders than recycle it.
This could be about to change. According to the Re-Road project it should be possible to raise the use of recycled asphalt to as much as 99%.
Dr Björn Kalman of the Swedish National Road and Transport Research Institute (VTI) and project colleagues from 13 other European organisations are aiming to develop a suite of innovative technologies to improve the quality of recycled asphalt so it can be used more widely on European roads.
Using a combination of laboratory approaches, computer modelling and field trials, they hope to present recommendations and proven technologies for the use of recycled asphalt in many road-building situations.
In addition to the current costs of recycling, reclaimed asphalts are complex materials according to Kalman, the project's leader. Impurities can mean that recycled asphalt is unsuitable for inclusion in roads that are under intense use or are exposed to large temperature variations. These lingering doubts about quality mean that some sectors of the asphalt industry have remained cautious about recycled asphalt use.
The Re-Road project hopes to answer these criticisms. Organised largely according to how asphalt is recycled, the project aims to develop technologies for characterising recycled asphalt and analyse how inclusion affects the durability and quality of final mixes. The processes used to produce recycled asphalt are also under scrutiny and it is hoped that an innovative modelling approach will speed up development times of new mixes.
The major concern of the project however, is to look for ways to reduce consumption of natural aggregates and decrease amounts of waste produced when roads are rebuilt. Clearly recycling and re-using asphalt more would help achieve this at a European level.
The successful development of recycled asphalt technologies will help reduce CO2 emissions from the asphalt laying process, reduce the amount of asphalt disposed of in landfill sites and reduce the risk of dispersion of hazardous substances from waste asphalt, for example.
Currently, reducing construction and demolition waste remains a high priority for the EC because of the quantity ending up in landfill and potential environmental hazards. This is ahead of forthcoming legislation that proposes a ban on landfill disposal of demolition waste by 2020.
The project continues until the end of 2012, when it is expected that recommendations will be made to industry and the EC on how recycled asphalt should be used. With 300 million tonnes of asphalt produced each year in Europe and over 10,000 companies involved in the production or laying of asphalt, it is expected the final project report will be eagerly anticipated.
In the meantime, it is probably wise to cast your eyes back on that road ahead again. That bus has just driven off.