Fleets of gritting machines spreading salt and gravel on the roads are usually an important part of ensuring motorists can make their journeys safely through the winter.
But a new type of road surface developed by chemists could soon see streets and highways de-ice themselves in the future.
Researchers have combined a salt with a synthetic form of rubber before adding it to bitumen, a major part of asphalt used to cover road surfaces.
They found while the bitumen was still as sturdy as it would be normally, it was able to resist the formation of ice on the road surface.
The new material could help solve the problem of salt and grit washing off the road by rain or the melting snow, meaning authorities need to constantly re-grit the streets.
It could also help make pavements safer as they are often left untreated, meaning pedestrians can have a treacherous journey in the winter.
Writing in the journal Industrial and Engineering Chemistry Research, Dr Seda Kizilel, a chemical engineer at Koc University in Istanbul, and her colleagues, said: ‘Ionic salts as anti-icing agents have been extensively used to eliminate accumulation of ice on asphalt surfaces.
‘However, salt can be easily removed by rain or automobiles and requires frequent application on roads.
‘Incorporation of hydrophilic salts into bitumen, a hydrophobic asphalt binder, and controlled release of specific molecules from this hydrophobic medium can provide an effective solution for reducing ice formation on pavements.’
The researchers developed a new way to combine the salt potassium formate with the synthetic rubber styrene-butadiene-styrene.
When mixed with the bitumen, it created ‘salt pockets’ which slowly released salt to help keep surfaces free of ice.
This is because adding salt to water lowers the freezing point and so means it has to be much colder before ice will form.
Tests in a lab showed the salt was released from the bitumen at a rate of around one to 10 per cent over a three-month period.
Dr Kizilel and her colleagues, whose work was funded by Turkish Petroleum Refineries, said this means the road and sidewalk surface could retain its de-icing capability for years after being laid down.
‘The results demonstrate the potential of this polymer composite-modified bitumen for anti-icing functionality and for industrially relevant applications,’ they explained.