Researchers at ULB are developing a construction material that requires neither cement nor water and is capable of self-repairing its own cracks. This self-healing sulfur mortar represents a major step forward in the development of circular, sustainable construction materials that require little maintenance and contribute to the climate transition.
An Alternative to Cement to Reduce the Carbon Footprint
The construction sector is currently responsible for nearly 9% of global CO
2 emissions. That is why researchers around the world are developing alternatives to traditional cement. Sulfur mortar is a particularly promising solution. Unlike conventional concrete, it contains neither cement nor water but is made from sulfur, a byproduct of the oil and gas industry that is currently often stored without being put to any practical use. This material also has another major advantage: it is fully recyclable, since it can be heated, reshaped, and reused multiple times.
The Challenge of Cracks
Until now, however, a major challenge remained. When cracks appeared during the lifespan of the sulfur mortar, there was no effective method for repairing this damage without completely replacing the affected component.
A team of researchers--BATir, Brussels Polytechnic School, ULB--has found a solution.
By incorporating a small amount of graphite into the sulfur mortar, it becomes sensitive to microwaves. When a cracked element is briefly exposed to microwave radiation, the graphite locally heats the sulfur, which melts, flows into the crack, and then solidifies again. The material is thus able to repair itself without any intervention or replacement.
"This is the first time we have demonstrated that a sulfur mortar can be repeatedly repaired using microwaves," explains Professor Didier Snoeck, who led this research at ULB.
"We are thus taking an important step toward self-healing construction materials that are truly usable in practice. This technology could not only extend the lifespan of infrastructure but also significantly reduce maintenance costs and environmental impact."
Smarter and More Sustainable Infrastructure
According to the researchers, this technology paves the way for a new generation of "smart" construction materials that can be installed locally and repaired in a targeted manner without requiring major infrastructure work. It is of particular interest for harsh environments, such as sewer systems, chemical plants, or industrial infrastructure, where traditional concrete deteriorates more rapidly.
From Earth to Space
The findings are also of international interest. Sulfur concrete is already considered a promising material for future lunar and Martian missions, since it does not require water during its production. Thanks to these new self-healing properties, it becomes even more attractive, both for applications on Earth and for future space structures.
Published on September 5 in the journal *Construction and Building Materials*, this research was conducted as part of the ARC HeSCon (Sulphur Concrete) project.
Wang, Q. & Snoeck, D. (2026). Microwave-induced healing ability of sulfur mortar with graphite. *Construction and Building Materials*, 538, 147343.
