UK roads are melting during the ongoing heatwave, but Indian roads remain intact even above 45°C. Here's how different asphalt, bitumen grades and climate-based engineering make the difference. (AI generated image)

Why UK roads melt in humid weather while Indian roads survive 45°C and beyond

The UK heatwave has raised a common question: why do roads start melting at around 40°C in Britain, while Indian roads withstand much higher temperatures? The answer lies in road engineering, asphalt and bitumen used in each country.

by · India Today

In Short

  • UK roads use softer bitumen for cold weather
  • Indian roads use harder asphalt for extreme heat
  • Road design changes based on local climate

Europe is battling an intense UK heatwave, with temperatures nearing 40°C in several places. Reports of UK roads melting have surprised many, especially in India, where temperatures often cross 45°C without roads softening on such a large scale. So why does this happen? The answer is not that British roads are poorly built.

It comes down to road construction, the type of asphalt and bitumen used, and the climate each country's roads are designed to handle.

Engineers in both countries build roads to suit their usual weather conditions, not rare extremes.

WHY UK ROADS MELT IN HEAT

Roads in the UK are also built using asphalt, a mix of aggregates and bitumen. However, the type of asphalt used differs from India's.

Britain commonly uses Hot Rolled Asphalt (HRA) and dense asphalt concrete. HRA contains finer aggregates and a higher amount of bitumen, making the road surface comparatively softer.

The bitumen used in the UK is also softer because roads there must cope with long, freezing winters. Soft bitumen stays flexible in low temperatures and helps prevent roads from cracking when the weather drops below freezing.

WHY INDIAN ROADS HANDLE HIGHER TEMPERATURES

India faces much hotter summers every year, so roads are built differently.

Indian roads generally use harder VG-grade bitumen such as VG-30 and VG-40, along with bituminous concrete containing larger aggregates. This combination is designed to withstand high temperatures and heavy traffic.

Because the bitumen is harder and has higher viscosity, Indian roads are less likely to soften even during extreme heat. They also resist rutting and deformation under heavy vehicles.

IT'S ABOUT CLIMATE, NOT QUALITY

The difference is mainly about engineering for local weather.

UK roads are designed to survive harsh winters, where flexibility is more important than heat resistance. Indian roads are built to perform in prolonged high temperatures, making them better suited to extreme summer conditions.

That is why temperatures close to 40°C can soften road surfaces in parts of Britain, while Indian roads usually continue to function even when the mercury climbs well above 45°C.

- Ends