Heat melting district’s roads

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While the region is experiencing a welcome downpour, the recent heatwave has caused the Gore district’s roads to melt.
Melting bitumen on roading throughout the district is keeping Gore District Council roading staff busy.
Council transport manager Peter Standring said road surfaces were designed to cope with the particular temperature ranges of different particular regions.
The Gore district’s bitumen was designed for a lower band of temperatures, he said.
“We’ve had successive days of 30-plus [temperatures]. [The seal is] operating out of its zone,” Mr Standring said.
“We have actually been out there from before Christmas getting grit on the roads.”
Roads throughout the South Island were melting because of the heatwave, he said.
Central Otago was also badly affected by melting bitumen.
When a road was sealed, a layer of stone chips was put on top of the bitumen, but during sustained hot weather the bitumen was “activated” and rose through the stone chips.
Council trucks were constantly on the road inspecting and gritting roads where necessary.
When the bitumen melted, motorists could lose traction and road markings become obscured, he said.
The council was keeping an eye on areas near stop signs, downhill sections and high-speed zones where traction might be compromised.
“It’s going to be a bit of mission to tidy this up.”
The council would have to wait until roads cooled thoroughly before repairs were carried out.
It might be March before repairs could be considered.
The process might include re-chipping road surfaces and painting new markings, he said.
One option was water cutting, where excess bitumen was removed by the high-pressure application of water, he said.
A forecast of costs and the scope of work required was yet to be carried out.
Some “self-healing” always took place when the gravel applied during hot periods became embedded in the bitumen and created a good surface again, Mr Standring said.
Mataura Community Board chairman Alan Taylor said damage to roads caused by melting bitumen was worse on roads regularly used by heavy vehicles.
An impression had been made on a stretch of Main St, Mataura next to the former Mataura Railway Station where trucks turned, Mr Taylor said.
“It’s putting the pressure on things with the constant heat and probably not cooling down much at night,” he said.