Concrete roads: the low carbon option

Britpave, the infrastructure group, has published a new guide as to why concrete roads are, in fact, the better whole life low carbon option.

‘Making the case for concrete roads’ explains how for a wide range of reasons, concrete roads offer a better long-term solution for the national and local highway networks. Not least of which is their unrivalled long-term performance that requires minimum maintenance. This means that over a 50-year performance life concrete roads do not have the high level of carbon emissions resulting from major maintenance or replacement compared with other road finishes. In addition, unlike other pavement solutions, concrete roads offer high level of resilience against the impact of extreme weather events. This again means less maintenance or replacement which in turn means less lifetime CO2 emissions and less whole life costs.

The new guide also presents the significant potential fuel savings to be gained from driving on concrete roads. A number of research studies have found that the stiff and rigid pavements of concrete roads reduces the fuel consumption of heavy goods vehicles. The reduction is due to the decreased rolling resistance between a vehicle’s wheels and the rigid road surface. The research reports fuel savings of up to 6.7%. It is estimated that a 100km concrete road with a daily traffic flow of 5,000 to 15,000 heavy goods vehicles would, over a 30-year period, save up to 400,000 tonnes of CO2.

There is also a growing understanding and appreciation of the carbonation of concrete. After manufacture, cement undergoes a "carbonation" process wherein the concrete exposed to CO2 and humidity slowly bonds with the CO2, storing carbon in mineral form. Because concrete is porous it can absorb CO2, carbonating and absorbing CO2 to a depth of 60 mm or more over a number of years.

Last, but not least, concrete roads can be part of a virtuous circle. When they reach the end of their functional life, concrete roads can be recycled to provide aggregates for new roads.

“Concrete roads are often mistakenly maligned as being unsustainable”, said Joe Quirke. “When, in fact, over their long performance life coupled with new low CO2 cements can more than negate their initial construction embodied CO2.”

To download a copy of ‘Making the case for concrete roads: visit: www.britpave.org.uk/publications