Europe is currently witnessing an intense heatwave, with several countries recording record-breaking temperatures. As the mercury continues to soar, reports of roads in the United Kingdom softening and suffering heat-related damage have attracted widespread attention. The situation has also prompted comparisons with India, where temperatures frequently exceed 45 degrees Celsius during the summer, yet roads generally remain intact.
Let’s find out why this happens, and the answer is not that one country builds better roads than another.ย
Why UK roads melt in heat?
Countries such as the UK primarily build roads using asphalt, a mixture of aggregates and bitumen. However, the composition of the asphalt differs significantly from that used in India.
European roads commonly use materials such as hot-rolled asphalt (HRA) and dense asphalt concrete, which contain a higher proportion of bitumen and finer aggregates. This gives the road surface greater flexibility, allowing it to expand and contract without cracking during harsh winters.
The UK uses softer grades of bitumen because its roads are designed to withstand prolonged periods of freezing temperatures. Softer bitumen remains flexible even when temperatures drop below freezing, helping to prevent cracking and structural damage caused by repeated freeze-thaw cycles.
Why do Indian roads survive harsher summer heat?
Every year, India experiences far more intense summer temperatures, and its roads are engineered accordingly. Most Indian roads are constructed using harder VG-grade bitumen, such as VG-30 and VG-40, along with bituminous concrete containing larger aggregates. This combination is specifically designed to withstand extreme heat as well as heavy traffic loads.
The higher viscosity and hardness of these bitumen grades make Indian roads far less susceptible to softening during heatwaves. They also offer greater resistance to rutting, deformation, and surface damage caused by heavy vehicles.
What’s the difference?
The main difference is that roads are built according to local weather, rather than following a single method.
In the UK, roads are designed to withstand long, freezing winters, where flexibility is essential to prevent cracking caused by repeated freeze-thaw cycles. In contrast, Indian roads are engineered to endure prolonged periods of extreme heat, with a greater emphasis on resistance to softening and deformation.
As a result, road surfaces in parts of Britain can begin to soften when temperatures approach or exceed 40ยฐC, whereas roads in India are generally capable of withstanding temperatures well above 45ยฐC.
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