Marcin Sundins research focused on sustainable concrete
5 December 2025
Sustainable concrete stands up to heat
The construction industry faces two major challenges: reducing its climate impact by using new materials, and at the same time maintaining high structural strength. New research in building materials at Luleå University of Technology now shows that low-carbon concrete can actually withstand fire better than conventional materials.
“We know that cement is a major source of carbon dioxide emissions, and that alternative materials come with their own challenges. Our research now shows that we don’t have to compromise. It is possible to develop climate-smart concrete that also withstands extreme conditions such as high heat,” says Marcin Sundin, researcher in building materials at Luleå University of Technology, who highlights these findings in his doctoral thesis.
In his thesis “Performance of Lower-Carbon Concretes After High-Temperature Exposure,” he studied how different types of concrete react when exposed to high temperatures, such as during a fire. By partially replacing traditional cement with alternative binders such as slag from the steel industry or calcium sulfoaluminate cement — a material that cures quickly, develops high early strength, and produces few shrinkage cracks — he analysed how these concretes change both chemically and structurally after heating.
The results show that many of the climate-friendly concrete types maintain their strength even after intense heat exposure. In some cases, they performed even better than conventional concrete.
“It’s about understanding how the material behaves on a microscopic level. When we know that, we can design concrete that has both low climate impact and high safety,” says Marcin Sundin.
These new insights could play a significant role in how future buildings are designed.
“Low-carbon concrete that can withstand high temperatures not only means lower emissions during production, but also greater fire resistance and increased safety in built environments. This knowledge can be used both in new construction and in the renovation of older structures,” he says.
The research has practical applications for the construction industry, where the results can help improve existing products, methods, and building standards. Marcin Sundin’s findings may also support a more circular building sector. He has shown that using industrial by-products — such as slag or even eggshell powder — reduces the need for virgin natural resources extracted directly from the environment.
“There are major benefits to making use of materials that already exist in other industries. In this way, we reduce waste and create value across multiple stages,” he says.
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