A major subject of conversation in the UK in recent weeks has been the intense heatwave during mid-July that saw peak temperatures exceed 40 degrees C, or 104 degrees F.
Not all of the UK’s current transport infrastructure stood up well to the challenges posed by the elevated heat. But what factors seem to have made the UK’s roads particularly susceptible to the adverse effects of the heat, compared to countries in mainland Europe?
Matthew Lugg OBE, international highways expert and Immediate Past President at the Chartered Institution of Highways & Transportation (CIHT), has recently weighed in on the subject.
Are older materials to blame for the issues seen on some UK roads amid the recent heat?
When questioned on why the material used to build roads in warmer countries than the UK – such as Spain – did not show the same problems during times when temperatures were especially high, Mr Lugg explained that in Mediterranean countries, the custom was for road materials to be designed to cope with a higher temperature range.
He said that this temperature range was typically between -5 degrees C and 50 degrees C, as opposed to the range of -20 degrees C to 30 degrees C that was typically used in the UK.
He explained: “As a result of previous heatwaves in the 1970s and 1980s, the specification for road materials was improved to include poly-modified binders which are far more resilient to higher temperatures.
“A lot of the current damage that is happening on the local road network is caused by older road surfacing materials that are less resilient to heat damage than the newer products.”
A call for “increased and consistent” investment in the maintenance of UK highways
Mr Lugg further explained that air temperatures going above 30 degrees C would cause the temperature of road surfaces to reach as high as 50 degrees C, due to the dark road surface absorbing heat – which, in turn, can lead to the melting of the bitumen in the road surface material. Stress caused by road users, he said, exacerbated the damage.
He continued: “Roads melt because the bitumen softens and then loses its adhesion to the stone.
“Damage to concrete roads and runways can often occur if the built-in expansion joints have not been properly maintained and this can cause the road surface to buckle. CIHT has consistently called for an increased and consistent investment in local highway maintenance.”
This is an assessment that we can very much agree with – indeed, it was only in 2020 that CIHT set out a number of recommendations to Government based on throwing fresh focus on the local highway network, including creating a new vision and making funding available.
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