East Devon’s residents might have been forgiven for thinking they’d had too much sun after seeing the gritters out this afternoon (Friday).
The beast from the east is not expected to make a comeback but record high road temperatures during the heat wave have seen road surfaces melting.
Surface temperatures on roads in Devon have reached as high as 60°C – 10 degrees higher than the temperature at which road surfaces can start to melt.
In East Devon, areas treated include melted road surfaces around Woodbury Salterton.
A Devon County Council spokesman said: “Surface temperatures on some roads this week have reached as high as 60°C and as a precaution we have been applying fine sand to help prevent the bitumen from becoming soft.
“We are monitoring all main roads across the county, particularly those that have recently been surface dressed or are in exposed areas.”
Tarmac becomes soft at 50C, and while the air temperature is much lower, the roads can become that hot in direct sunlight.
Speaking last year, Howard Robinson, chief executive of the Road Surface Treatments Association, said that when temperatures top 30C, the bitumen in some road surfaces may soften and rise to the top.
“Most roads will not begin to soften until they hit a temperature of around 50C.
“However, even a sunny day in the 20Cs can be enough to generate 50C on the ground as the dark asphalt road surface absorbs a lot of heat and this builds up during the day.
“The response for local highway authorities is to send out the gritters to spread granite dust or sand to absorb the soft bitumen and so stabilise the road surface and make it less sticky.
“Drivers may be bemused to see the gritters out in the summer when they are usually spreading grit and salt during the winter.
“However, this is effective standard practice for keeping a road surface safe during extreme hot temperatures.”
He continued: “Asphalt is like chocolate – it melts and softens when it’s hot, and goes hard and brittle when it’s cold – it doesn’t maintain the same strength all year round.”
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