The first green sleepers in Europe will be seen in Belgium. The production of the sulfur-based units started yesterday at the site of manufacturer de Bonte in Henegouwen, Belgium and infra manager Infrabel has already placed the order of the first 200,000 units.

The sleepers owe their green title not only to their colour, the units are more ecological than the traditional concrete sleepers. They produce 40 per cent less CO2 emissions, are fully recyclable and last for 40-50 years. But this is a revolutionary concept, as there is currently no infrastructure in Europe that is making use of the green sleepers.

200,000 sleepers in 8 years

The Belgium manufacturer de Bonte won Infrabel’s tender in 2020. Infrabel ordered 200,000 sulfur concrete sleepers at a rate of 25,000 per year for 8 years. This order is the direct result of a government contract awarded to De Bonte in 2020. In this tender, Infrabel introduced, for the first time, various environmental criteria for the selection of a supplier. In the future, Infrabel plans to include these environmental criteria in new tenders.

Since then, the order book of de Bonte has been filling up. The ambition of the company is to conquer the whole world with the concept, and it is currently making a start with this expansion by having talks with companies in France and the Netherlands. Infrabel is equally willing to play the pioneering role, and showcase its commitment to carbon reduction as an example to other infrastructure managers.

“By using green sleepers in future construction sites, the infrastructure manager will be able to save 6,000 tons of CO2. That corresponds to the annual CO2 production of 100 Belgian households”, the company says.

The benefits

Sulfur concrete sleepers last 40 to 50 years and have a resistance to dynamic train loading that is at least as good as that of traditional cement-based concrete sleepers. Sulfur concrete is less porous than conventional concrete and therefore less susceptible to water ingress. But above all, there are three important environmental benefits:

• 40 per cent less CO2 emissions than the production of concrete sleepers. Sulfur replaces cement and water as binders and is mixed directly with the granulates. This avoids the energy-intensive process of converting limestone into cement, which releases large amounts of CO2. In addition, sulfur concrete only needs to be heated to 140°C before pouring, while a temperature of 1400°C is required for cement manufacture.
• Fully recyclable: a sulfur concrete sleeper can have several lives. Because the material can be melted and hardened again and again. It is therefore 100 per cent circular and can be completely reused to make a new sleeper.
• Waste recycling: Sulfur concrete makes it possible to recover sulfur, a waste product of the oil industry.