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From oil to algae: eco-friendly asphalt could be the route to greener roads
June 8, 2015
From oil to algae: eco-friendly asphalt could be the route to greener roads
Rich McEachran
Monday 8 June 2015 13.38 BST
The process of surfacing a road isn’t complicated. Layers of asphalt, which is composed mostly of bitumen (a byproduct of crude oil distillation), are poured over an aggregate of crushed stone and sand; the asphalt acts as a glue, binding the mixture together to form asphalt concrete.
Maintaining the roads, however, is a costly job. According to the Asphalt Industry Alliance it would cost more than £12bn to restore all road networks in England alone to a reasonable condition.
Simon Hesp, a professor and chemical engineer at Queen’s University in Ontario, believes standard industry asphalt is not sustainable. “The problem with the composition is that it’s poorly controlled … it uses materials with poor performances,” he says. Hesp says the presence of certain oil residues lowers the quality of the concrete and is a key reason why roads are failing and many potholes need to be filled and cracks fixed.
But there’s not just a maintenance cost. Asphalt, dependent as it is on the oil industry, is resource- and energy-intensive, which is why the race is on to develop a greener alternative.
In Sydney an experiment is under way using printer toner waste blended with recycled oil to produce an environmentally friendly asphalt. And in the past few years there have been studies into the development of non-petroleum bioasphalts.
Read more at The Guardian.
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