Barrett Byrd Associates

Colas is introducing to the UK a product that presents huge opportunities for reducing the carbon footprint of road maintenance – an entirely non-crude oil based binder called Vegecol.

It looks like refined crude, but the bag of viscous fluid on the desk of Colas UK business manager Carl Fergusson does not contain a single hydrocarbon from refining oil. Vegecol, as Colas has called it, is an entirely vegetable based alternative to bitumen and petroleum resin binders and so carries massive potential for the pavement sector.

For highway authorities and other clients, Vegecol could mean a massive reduction in energy consumption and a decoupling of projects from rising crude prices. Use of this new material allows an asphalt mix temperature as much as 40⁰C lower than the norm, meaning lower fuel consumption and fume emissions at the plant. And lacking hydrocarbons, asphalt made with Vegecol does not degrade when in contact with fuels.

Colas UK’s parent company Colas SA manufactures Vegecol at Vitrolles in southern France and is guarding the secrets of the binder’s manufacture, although the French Patent gives the material’s constituents as ‘purely natural or modified natural substances of agricultural vegetable origin’.

In Europe, use of Vegecol has extended to surface and base course asphalts and the Vitrolles plant is now producing the binder at a rate of about 1000t per year. According to Fergusson, Vegecol is for use wherever Colas operates geographically and potentially, wherever bituminous binders are normally used.

“Vegecol is a product of our parent company in France that we have latched onto as a tremendous innovation,” says Fergusson. “There are huge opportunities for its use, given the way prices of oil and bitumen are going. Colas has spent over 100M Euros on research and development over the past year. If we want sustainable business, we have got to be investing in alternatives to oil and bitumen. I have heard one major oil company spends more on developing alternatives than it does on oil exploration.”

The Vegecol sample is in a plastic bag on Fergusson’s desk because Colas has recently used the material as the binder in a UK pilot project, resurfacing a footpath in Portsmouth. Vegecol is a ‘transparent’ binder and so produces naturally aesthetic or coloured asphalts with addition of decorative aggregates or pigment.

“The UK target market for Vegecol is initially heritage sites and both local authority and private sector estates, but ultimately, anywhere bitumen is used, Vegecol can be used instead,” Fergusson says.

“Colas has already carried out surface dressing in Germany with Vegecol as the binder, and surface and base course asphalts have been developed and laid with Vegecol in Belgium, Hungary and Martinique. It has also been used as the binder in an in situ asphalt recycling process – the ultimate in environmentally friendly resurfacing.”

In Portsmouth, coloured asphalt containing Vegecol has been used to resurface footpaths in Jack Cockerill Way, through Colas’s 30 year PFI road maintenance contract with the city council. Vegecol is manufactured in bulk at Vitrolles, but with only a relatively small amount needed for the pilot scheme in Portsmouth, the binder was delivered in 1kg bags.

“This was less than ideal for handling, but everything else with regard to the asphalt production, bar the lower temperature, was as normal with conventional mix and laying plant used,” says Colas technical manager for asphalt and quarries Steve Cant. “The usual precautions with clear or coloured mixes regarding cleaning of equipment must be taken, but the work in Portsmouth was based on a standard asphalt mixture. We just replaced the bitumen binder with Vegecol and added pigment to get a deep red colour, although with a vibrantly coloured aggregate no pigment would have been necessary.

“The quality control was also the same as usual, with checks against the grading of stone and binder quantity. There are different methods for testing the binder in France, but the production and testing for asphalt containing Vegecol remain the same as for material containing bitumen.”

New UK asphalt standards harmonised with those in Europe came into force this month (January), with CE Marking of products, which currently remains voluntary in the UK, but is mandatory in France.

“The CE Mark serves as an assurance of quality, that the material has been produced to documented and auditable factory control procedures and type tested for performance related properties,” says Colas technical development manager John Richardson. “Vegecol is subject to a similar type of assessment and control, but there is no provision for its use in the harmonized standards.

How asphalt containing Vegecol is specified in the UK will depend on the client. Approval of departure from standard will be needed for many public sector roads because asphalt standards only talk of bituminous binders, which Vegecol of course, is not. However, for private sector clients also, we can back up Vegecol with test data and a long list of examples of its use,” Richardson says.

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“Fortunately we have a very strong track record in Europe,” Fergusson adds. “Marketing Vegecol in the UK will start with small use and build up gradually, but potential clients can be assured that the material has been tested to the maximum, as our colleagues in France are very careful to protect their reputation."