Building Greener Roads

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New roads are continually needed to reduce the travel time and distance for transporting people and products and other material from place to place. However, for each mile of these new but traditionally constructed roads, thousands of tons of materials such as aggregate stone, concrete, asphalt and steel are needed, let alone all of the diesel fuel required to power the construction equipment and to transport materials to and from the project site. One mile of two-lane asphalt road with aggregate base can require up to 25,000 tons of aggregate. In terms of greenhouse gas emissions, between the pavement and sub-base the mining of the aggregate, transporting, heating, earthwork and paving work will emit enough pollution to equal up to 2,200 tons of CO2. That's about the same as the total annual emissions of 400 passenger cars.

The environmental effects of a road do not stop when construction is complete. The new road affects local plant and animal life as well as the region's water and soils. The road acts as a barrier that cuts through animal ranges and creates a crossing hazard, further diminishing wildlife habitats, especially if trees were cleared to make way for the road.

While it is highly encouraging to see new efforts to green the transportation infrastructure (cleaner cars, light rail, urban mass transit), most of the world still goes to work each day on a road designed and built with yesterday's thinking.

So how can we reconcile the need for an improved and more extensive road infrastructure with the need to do so in a less damaging way? The answer lies in recovering and recycling existing in situ materials and utilising specially engineered binders to produce effective stabilised building materials that enable existing waste streams like pulverised fuel ash to be incorporated into the road sub strata.

To enable a number of innovative and eco-friendly engineered binders are being designed and tested. Among the most promising SMR a soil stabiliser and binder that provides the equivalent strength of aggregate base stone at less cost and environmental impact. Proving that green road innovations can provide benefits across the sustainability value chain and enabling greener construction, residential developments, schools and the rest of the built environment.

Innovations like SMR will have to contend with agencies and individuals wedded to the old way of doing things. The task is no easy matter, as these agencies can be burdened with bureaucratic inertia and bias toward existing industries and technologies. That said, HAUC the UK Highways Authority and numerous local authorities are starting to recognise that the industry and overall approach to road building is due for a change, especially given the current economic climate that is forcing local authorities do more with less.

While there is still a long way to go, the long term target is to build a road that reduces toxic and greenhouse gas emissions, reduces landfill use, reduces mining non renewable resources and protects ecosystems.

There remains one other reason why green roads are so important requiring a solution now and not tomorrow. In order compete the developing world has to build road networks, millions of kilometres will have to be constructed over the next 10 to 20 years. in Africa, India, China, Russia, the Far East and Latin America.

To use the same old construction methods would lead to unprecedented environmental impact and a further unnecessary contribution to global warming, all while incurring great economic costs to their fragile budgets. Now is the time to embrace a new way to design, plan, build and maintain road infrastructure, consistent with green road building practices.

In the developing world, every single mile of road built is associated with a significant economic return, as reduction in travel times and costs improve all factors of life.

Whilst road construction has the most impact on people in the rural countryside by 2050 the world's cities will see their populations expand by over 3 billion. All that growth will bring with it a massive new demand for infrastructure. Green roads in conjunction with modern power grids, cleaner cars, large and dependable public transportation systems will help to greatly reduce the per capita carbon footprint of these thriving mega-urban regions.

Old ways of road construction need to be reviewed and new approaches to road construction tried. Just as the green building movement has finally reached the spotlight and gone mainstream, the green roads movement should not be is not far behind.

For more information on recycling aggregates and turning waste in to an engineered for purpose material have a look at: http://www.soilstabilisationsolutions.com