Costain brings local green solutions to National Highways’ A30 road upgrade in Cornwall

Costain is delivering nine miles of dual carriageway to unlock congestion on the last remaining single carriageway section of the A30 between the Chiverton and Carland Cross roundabouts near Truro. Cornwall’s very own china clay mining industry is playing a big part in the construction of this major road upgrade.Costain’s Climate Change Action Plan sets out an ambition to lead UK infrastructure into a zero carbon future by 2035 at the latest, so sustainability and reducing the carbon footprint are key drivers behind construction of the 8.7-mile dualling scheme. To that end Costain, design partner Jacobs, and construction solutions supplier Aggregate Industries are tapping into natural Cornish materials and a significant investment in local companies.Larger infrastructure projects typically use millions of tonnes of aggregate – representing a large carbon footprint – but as with other modern-day road building schemes, the A30 project is utilising a by-product from the China clay mining industry.The residue, known as stent, would normally have no use and be left in white spoil heaps, scarring the local landscape. Instead, the material from the Littlejohns Pit near St Austell is being processed into sustainable secondary sand and aggregate for construction use.And just down the road, this is now being used as an engineering alternative across the A30 project, not only reducing the embodied carbon but also saving on the transport carbon cost.Compared to the 5kg CO e per tonne carbon emission of virgin aggregate, the locally imported material is around 2kg CO e per tonne, representing a reduction of around 3kg CO e per tonne of aggregate used.