The soft asphalt from old tires can save bones and lives

The pandemic continues and many of us are still isolated or working from home. When the spring sun shines through the window, it can be tempting and healthy to walk, run, or ride a bike.

But even a spring hike can be risky, especially if patches of ice remain or winter gravel hasn’t been cleared from the sidewalk yet.

– All risk groups must walk. When many people switch from water aerobics and other types of exercise to simply walking, it is very important not to incur fall accidents that, like COVID-19, can be life-threatening, says Viveca Wallqvist of the state research institute. Rise, Swedish Research Institute. .

Every year, 70,000 people must be hospitalized after a fall accident. 50,000 of them are 65 or older, according to the National Board of Health and Welfare, and probably about a third of accidents occur outdoors. In addition, more than 23,000 injured cyclists a year seek emergency room care, according to the Swedish Civil Contingencies Agency, MSB. More than 80 percent of them have had a single accident, and of the rest, about half have collided with another cyclist. Also, new types of vehicles. In 2019, there were more than 600 electric scooter accidents, reports the Swedish Transport Agency.

– Accidents with electric scooters are increasing more and more. They are mostly held on Friday and Saturday nights, when, for example, you misjudge how high the edge of a street is and drive straight into it. Many have been so injured that they have a reduced ability to work, says Viveca Wallqvist.

The risk of falls It can be prevented with snow removal, sanding, sweeping, and better, smoother surfaces in pedestrian and bicycle lanes. But once someone trips and falls, there is still no easy way to alleviate the damage.

– Cyclists have bicycle helmets, but for pedestrians we have nothing at the moment, says Viveca Wallqvist.

His suggestion is to smooth the surface.

– If you fly over the handlebars of your electric scooter and land on a more forgiving tarmac, you can avoid that fracture in your hand so that you can continue to hold your pen, instrument, or brush, or whatever you’re working on, she says.

Soft asphalt would also save lives.

– We have vision zero, which has been a fantastic success for vehicles. It shows that when you decide on a goal and before action, you can dramatically reduce the number of serious injuries and deaths in traffic. But right now, about 70 percent of the seriously injured in traffic are cyclists and pedestrians.

Together with his companions Viveca Wallqvist has developed a soft asphalt for pedestrian and bicycle paths. The type of asphalt we normally use on roads was invented in 1870 by Edwars de Smedt, a Belgian-American professor at Columbia University in New York. It is a mixture of crushed stone and binder bitumen, a waste product of oil refineries. On softer asphalt, Rise researchers replace the stone with rubber from old car tires.

– It’s a bit of a circular thought. This is a very nice material that there is no shortage of. “I have calculated that if you put all the car tires that are made for a year next to each other, they would cover the whole of France,” says Viveca Wallqvist.

In most of the world, used car tires are disposed of only in landfills.

– In warmer countries, they become easy havens for malaria mosquitoes and other insects that spread infection. Our vision is that we should instead recycle the material and take advantage of its fine properties. That is the beauty of this solution. When the car’s tires have rolled, we leave them on the road so that road users can take them there.

There are other environmental benefits as well.

– Crushed stone is usually used. It is a finite material that is extracted in quarries. It takes energy to break stone, and in some places it can become a rare commodity. Using recycled car tires will also be an elegant solution to that problem, says Viveca Wallqvist.

Summer 2017 Researchers tested soft rubber asphalt for the first time on a bike path in Uppsala.

– It works well. It has been there for three years without any other impact.

This summer, a new, more extensive experiment was carried out with a 300-meter long pedestrian and bicycle lane in Lund. It attracted media attention.

– It was very marked before we built that course. We were in the middle of Lund and we played the kick drum. The cobblestones thought it was a great material to work with, and I was looking forward to going back and taking pictures of happy bikers. But we count the victory in advance, says Viveca Wallqvist.

It was not as good as in Uppsala. The rubber asphalt in Lund quickly lost its surface and began to crack.

– It was a line on the bill. They are quite high costs when such large volumes are invested. But research is always full of ups and downs. Now we have to go back to the lab and find out what happened.

One possible explanation is that the asphalt rubber absorbed the binder so that the asphalt no longer held together. Now the researchers are investigating whether it is possible to pretreat the ingredients in another way to avoid it in the future.

Despite the setback There are many young researchers and students who want to be part of the project.

– The students are very attentive to this and they say “Oh, this can save us when we get old!” Normally I think: now you are 20 years old, it takes a while before you get old, says Viveca Wallqvist.

Researchers are also investigating what opportunities exist to replace fossil-based binder bitumen.

– Now a lot of research is being done to find alternative sources of aviation and automobile fuel, and then you will no longer have safe access to bitumen. Then we must also find other sources. You can look at the production of, for example, jet fuel from other raw materials and see if there will be something sticky enough that we can take to the roads in the future, says Viveca Wallqvist.

He has many ideas about possible raw materials for the roads of tomorrow.

– We have talked about completely innovative sources, as if you could build roads with banana peel. It may be a bit slippery, of course. But it can be a completely different way of thinking in the future, where you don’t just think about where to build the road. You might think: “our municipality is an agricultural municipality, and we only build roads with residual products from our own farms.”