London’s streets represent a quality source of secondary aggregate for surfacing contractor FM Conway.
The streets of London may look paved with gold to some, but Tim Metcalf sees them as his company’s very own ‘linear quarry’. Tim is General Manager of FM Conway, one of the capital’s leading infrastructure services companies. Its commitment to developing sustainable ways of keeping London’s roads in good condition means that a lot of the asphalt material for new road surfaces and repairs is recycled, along with concrete and gully arisings.
“There is a shortage of natural stone quarries in the South East but focusing on recycling means we have a sustainable source of stone right under our feet,” says Tim. “We already manage and improve carriageways on behalf of 16 London boroughs and we think news of our proven commitment to using and developing sustainable ways of working will help convince others.”
Two of FM Conway’s strengths which it hopes will help secure future work are the company’s ability to recycle almost all of the bituminous material extracted from roads and its close proximity to the capital. FM Conway also operates a new asphalt plant beside the River Thames at Erith in North Kent, which processes virgin aggregates that arrive in a more sustainable fashion; by ship rather than by lorry.
“Our company is committed to recycling in a way that many other firms can only dream about,” says Operations Director Mike Betchley. “Almost all of the secondary materials and waste recovered from highway sites such as asphalt, concrete and gully arisings can be reprocessed and recycled back into the roads.”
Construction materials recovered from highways are crushed and screened by the company to produce Reclaimed Asphalt Paving. Organic matter such as gully arisings are reprocessed using a drainage treatment plant to produce sand and recover gully water.
Primary aggregates needed to produce many asphalt products for highway applications arrive into Erith via the River Thames. Around 250,000t of aggregate was brought in on ships last year, which reduced lorry movements by 15,000.
Various grades of crushed gritstone arrive from quarries in Northern Ireland and are unloaded from ships by a grab crane sitting on the end of a jetty, 120m out into the Thames. A conveyor belt carries the material into the asphalt plant and discharges it into one of several covered aggregate bays, ready for use.
Transporting virgin stone from the other end of the British Isles to be processed into asphalt surfacing may not seem to be very carbon efficient. But Mr Metcalf points out that “Shipping is the most environmentally friendly form of transport, more so than rail”. He adds: “The company’s carbon model is as low as it can possibly be,” and says that the new asphalt plant which opened two years ago has been designed to operate in a highly efficient manner. The plant saves 1350t of carbon emissions a year and reduces energy consumption by 7% compared to a standard asphalt facility.
Erith’s asphalt plant features two large drums to accommodate both primary and secondary aggregates. The plant operates around the clock, can produce up to 320t of asphalt an hour and stores 600t of hot material at any one time. Around 400,000t of asphalt was produced at the plant in 2011.
FM Conway plans to open a second asphalt production facility in west London soon to recycle highway arisings and produce surfacing material for use locally. “Opening a second asphalt plant will be important from a sustainability perspective,” says Operations Director Mike Betchley. “There is little point in us producing carbon friendly materials and dealing with recycled aggregates at Erith if we are only going to drive them to the other side of London and generate vehicle emissions.”
The company hopes that its recycling endeavors and investment in new facilities will stand it in good stead for future work not just with road authorities in London, but the Highways Agency as well.
Performance proved at the Port of Dover
Roads and parking areas at the Port of Dover have recently been resurfaced using a heavily polymer modified asphalt supplied by the company. The ‘SurePave’ material is based on the French EME2 asphalt design and was specified to provide a very stiff, rut resistant surfacing and to reduce the risk of heavy and slow moving vehicles from causing deformation to the carriageway.
Roads renewed in Westminster
Planned and emergency highway works in the populous London Borough of Westminster are looked after by FM Conway. Recent projects include renewal of asphalt surfacing around Piccadilly Circus where traffic now flows both ways rather than in one direction. The company also responded to a major flood along Oxford Street in January by reinstating damaged carriageway and laying 500t of binder course and 300t of surface course at very short notice.
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