Building sustainable concrete structures together in construction of Europe's largest carbon-neutral cement plant

In Obourg (Mons), Holcim is realizing Europe's largest CO2-neutral cement plant. The Go4Zero project symbolizes the future of the construction industry: a drastic reduction of the ecological footprint through innovative production processes, circular raw materials and smart technologies that extend the life span of concrete.

The modernization at Obourg marks the biggest turnaround in the site's more than 110-year history. Holcim is abandoning outdated, energy-intensive processes and opting for a high-tech drying line with limestone extracted from different, also new regions. This step immediately produces significant CO2 savings. In the next phase, oxy-fuel combustion and CO2 storage will be integrated, moving the plant toward virtually climate-neutral production by 2029. The result: some 2 million tons of cement annually with minimal climate impact.

Critical infrastructure 

Part of this ambitious project includes extensive underground structures: tunnels, foundations and technical rooms. These are exposed to moisture, high water pressure and chemical influences. To make these crucial parts as sustainable as possible, Holcim and contractors Besix and Denys chose Penetron's proven technology.

Self-healing concrete

Penetron Admix SB was chosen, added in the concrete plant. During the concrete pour and after curing, microscopic crystals form that permanently seal the pores and capillaries once they come into contact with water. This makes the concrete permanently waterproof and resistant to high pressure and chemical stresses. A unique feature is its self-healing ability: cracks up to about 0.5 mm are continuously and automatically resealed. Thanks to this technology, traditional membranes or coatings are unnecessary, which not only saves material, labor and costs, but also further reduces the CO2 emissions of the construction phase. Additional products such as Penebar SW provide a fully watertight solution without the use of additional non-circular materials.

Guidance and cooperation 

During execution, Penetron Benelux was in close contact with Holcim and the contractors. The technical specialists provided guidance on dosing, quality control and detail finishing (such as grouting and penetrations), ensuring maximum return on the technology in this prestigious project. 

Reference project for the future

The Go4Zero project proves that sustainable construction and innovative technology go hand in hand. Managing partner Olivier Suerickx: “For Holcim, it is the construction of a cement plant that is ready for the future. For Penetron, operating worldwide in more than a hundred countries, it is recognition of the contribution our solutions make to life extension and circular construction. That we as Penetron Benelux may contribute to this revolutionary plant, is a nice confirmation that our technology plays a key role in making buildings and infrastructure more sustainable.”