Meet Björn Kalman – scientist and hobby farmer

Björn Kalman, Research Director of the Swedish National Road and Transport Research Institute (VTI), is the kind of person who works widely in the field of road research and enjoys going into many areas in depth. If he is forced to choose one of the most important areas he has been involved in, he will happily name asphalt recycling.

Besides being the boss and everything that entails, he jumps between different research projects. These could be about binders and how they can be improved, the differences between them, how quickly they decay and how they can be recycled. In recent years, a great deal of work has also been put into research into electrified roads.

Another approach is how noise can be reduced with the aid of special surfacings – Björn Kalman believes that this research has great significance for the future.

“Noise reduction is a very interesting and enjoyable research area where there is much progress to be expected. It was Research Manager Ulf Sandberg who got me into this research,” he says.

Employment at VTI began when the institute was looking for a researcher in physical chemistry. As Björn Kalman explains, this is an unusual profile in job advertisements, on the borderline between physics and chemistry, with the emphasis on chemistry.

“I was working at Linköping University at the time. The advertisement made me curious about what the job might involve, what exactly it might be. The job was to perform research on binders like bitumen and polymers,” he says.

Björn Kalman had received his doctorate a decade earlier, in 1991, with a thesis on energy transfer between molecules.

“This gave a good background for understanding the microscopic forces that govern a material’s properties: for example, what governs adhesion between a binder and the stone material. If water have greater affinity to the stone material it can affect how the road surface is held together. When water gets into the asphalt, it may cause loss of aggregate and potholes.”

He believes it is also a good background for looking at the effects of ageing of materials, how oxidation of material change the properties the road material.

“Our research is often an interplay between many parties and it is always enjoyable to see the results implemented . Now and then, I think about how much of our research has been put into practice. It is very difficult to quantify, but we have definitely contributed to Sweden having much less road wear than would have been the case without us,” he says.

Sweden and the Nordic countries build roads differently with relatively thin structures, but the roads are still of high quality and have good durability – in spite of extra wear caused by studded tyres compared with many other countries.

His research area is aimed at sustainable solutions for the future and he provides a number of examples. It can be about replacing petroleum in bitumen with local, renewable plant-based products such as tall oil pitch. The infrastructure becomes more circular when more of the old road material is reused for road building purposes, such as when old asphalt is milled up and mixed with new, preferably at the same place so as to minimise transport.

Slag from incineration of waste will be increasingly used to replace crushed stone as an unbound material in a roadbed. With ever-improving purification methods, this is often a safe product from an environmental viewpoint. Road markings represent another area that will be developed in future, with new raw materials that do not come from fossil sources.

Besides being transport routes, roads, streets and other paved areas will have other functions, such as water reservoirs. Artificial intelligence could improve operation and maintenance by means of smarter planning and better ways of looking after the road network.

Cycle paths are becoming ever more important and will need to have a stronger and more sustainable structure. Electrification involves different types of vehicles, as well as heavier vehicles, which will bring new challenges for road construction.

Björn Kalman believes that VTI is good at going all the way by having an objective and achieving things.

“We often work on projects together with the stakeholders. We don’t research areas just because they are interesting but because there is a problem to solve. We pick out results that can be used straight away, by putting them into practice or into the rulebook.”

When Björn Kalman isn’t working at VTI, he’s something of an hobby farmer. The farm has an old house, a few sheep and a hay meadow to look after. Even as a boy, he was interested in nature and in birdwatching and began to learn new trades.

Research has affected his life in many ways.

“It’s great fun to be able to dig deep into a subject area in the way we do; it’s a bit of an ego trip. As a researcher, you are also better at judging other people’s research. We get a different understanding of what is relevant, whether there are connections and in what way.”

Text: Gunilla Rech

Translation: CBG