We’re passing by hotter than ever. At least that is the feeling we have when we watch the news, listen to the radio, read the news and, of course, go out. And worst of all, we expect the heat wave to come back stronger later this week.
And the temperature in the rest of Europe is also worrying. This year we have seen Finland record the warmest June since 1844. The image of cold and rainy London is almost nostalgic. In fact, they hope to reach 42º.
Records so anomalous that they are causing unexpected situations. United Kingdom It is not a country for heat. The realization is that its train tracks are warping and the roads are melting. What happens so that in Spain we do not have these problems with higher temperatures?
A road for every part of the world
Although at first glance it seems that they are all the same, the roads present small differences that the differences between countries. The technical requirements that they have to face are not the same in the cold Scandinavian and in the warm Córdoba.
And this is a real problem now that London and Cáceres are not so far away, meteorologically speaking. When a road is built, the volume of vehicles that will pass through it is taken into account, but also the volume of rain that it has to dislodge or its resistance to salt, in the event that ice sheets form.
In Spain, the problems are different. In most of our country, weather obsessions have a lot to do with high temperatures that we reach in summer. With the UK experiencing southern European temperatures, its roads are melting.
The asphalt that we walk on with our car is a mixture of stones and compacted sand on which a mixture of bituminous material is printed that gives resistance to the upper layer, but also the sufficient elasticity so that the passage of vehicles does not break the asphalt they walk on. This last layer used is a bitumen binder, which is not always used with the same consistency.
With said binder, a hard layer is generated on which the traffic rolls and, at the same time, serves as a bond for the lower layers of stones and sand. The more consistent this bitumen is, it is also less elastic. As it explains Francisco Jose Lucas Ochoatechnical and business development director at Repsol on his Twitter account, Spanish roads are built under the PG3 regulations which, in turn, are based on the European regulations.
Today, #MondayofRoadsit’s a good time to tell you a few things about what happens when it’s very HOT (like the last few weeks in 🇪🇦) and the ASPHALT on our roads.
It’s a recurring theme in the press, so I hope this mini will serve you 🧵 ⤵ pic.twitter.com/VuM4dHuIOM
— Curro Lucas (@curro_lucas) August 23, 2021
They specify the consistency that bitumen binders must have when building roads. In warm areas, a harder bitumen is used, those classified as 35/50, while in colder areas a 50/70 bitumen is specified, which is softer, but also reaches its softening point earlier.
This implies that the Spanish asphalt better resists high temperatures than the one used in the United Kingdom, but it is also less flexible and therefore more prone to breaking if the forces of the vehicles are not adequately distributed in the lower layers of sand and stones. Ochoa points out that the “internal friction of coarse aggregates” comes into play here.
Why do they use in the United Kingdom (and other cold countries in Europe) a less consistent bitumen? Because being more flexible it also better supports fatigue. In fact, the most consistent bitumens are also used on British roads, but they are intended for roads where heavy traffic circulates on a recurring basis.
How do we fix it?
Beyond the fact that the construction of new highways contemplates the effects produced by climate change and the appearance of extreme temperatures that are breaking historical recordsthere are other short-term solutions.
For example, gluing the asphalt and lowering its temperature. The idea of cold asphalt is not unique to the United States. In France, this same year, they try to lower the temperature of the asphalt with water. Shortly before the Tour de France cyclists pass through the established sections, a tanker truck waters the road to lower the temperature and reduce the risk of the ground melting.
Spreddie Mercury is all prepped and ready in case road surface starts to melt bitumen in tarmac – sometimes we spread sand using gritters to maintain the surface integrity.
— Richard Davies (@rgdavies) July 15, 2022
In the UK, for now, the strategy is to paste the asphalt material. In this case, you are choosing spread a small layer of sand so that, once the asphalt melts, it regains consistency. Thus, the ground regains its robustness and ensures that vehicles do not lose grip.
On other occasions, graphene has been experimented with, but also with using less dark colors for the asphalt or painting a larger surface white. In fact, this same strategy is being carried out on the train tracks in the United Kingdom, as has already been done in Austria, which is also suffering from high temperatures.
Another good example of how each asphalt is a world is cold asphalt. In the United States they have studied how to reduce the temperature of this surface to avoid damage in regions as extreme as Phoenix. The secret: add one more layer of asphalt, mixed, among other materials, with soap and water.
George is Digismak’s reported cum editor with 13 years of experience in Journalism