First scallop shell road opens in Calvados
Crushed scallop shells used to replace some cement, cutting carbon emissions from road construction
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Calvados has become home to France’s first road built using crushed scallop shells, in a project aimed at reducing the amount of carbon-intensive cement used in road construction.
The 2km experimental road, completed in June, uses a fine powder made from discarded scallop shells as a partial substitute for cement in the road’s foundation. The project will now be monitored for three years to assess its durability.
Producing cement generates large amounts of carbon emissions because limestone must be quarried and processed at high temperatures. Scallop shells, which are naturally rich in calcium carbonate, offer a lower-impact alternative for part of the material.
“It is a great source of pride, because it proves that departments can be part
of innovation,” Michel Fricout, a Calvados departmental councillor and vice-president of the council, told The Connexion.
He said the project also highlights one of the department’s most important industries. Calvados is France’s leading scallop-producing department, with between 10,000 and 15,000 tonnes landed each year. Its scallops carry the Label Rouge quality mark.
The idea came from Christian Chantreuil, a former director at road construction company Eiffage Routes, who recognised the potential of scallop shells as an underused resource.
A processing plant was later built in Calvados with support from the department and Eiffage Group.
The shells are crushed into a fine powder before being mixed with cement to form the road’s base layer. Once this has set, a conventional asphalt surface is laid.
“If you drive on that road today, you will not notice any difference,” said Hervé Dumont, strategic director at Eiffage Routes. “The wearing course, which gives vehicles grip, comfort and smooth driving in all conditions, is unchanged.”
Mr Dumont said the project could lead to wider industrial uses for scallop shells, including in pharmaceuticals, cosmetics and food production. With France consuming around 150,000 tonnes of scallops each year, he said there was no shortage of raw material for future projects.
