Waste-to-product company Renewi and construction materials producer Holcim are taking an important step together towards circular dike reinforcement. In the production of the innovative Basalton concrete columns, all naturally sourced sand is fully replaced with recycled sand from Renewi, derived from crushed concrete. This sand is KOMO-certified for use in concrete. The new columns are being used by Rijkswaterstaat and several water authorities in dike reinforcement and flood-protection projects.

Concrete is one of the most widely used materials globally and accounts for a significant share of CO₂ emissions. In the Netherlands, millions of tonnes of concrete waste are generated each year. By recycling this waste into high-quality raw materials for new concrete, scarce resources are conserved and the ecological footprint of the construction sector is significantly reduced.

Collaboration as a prerequisite for success

The partnership between Renewi and Holcim demonstrates that high-quality concrete recycling on an industrial scale is feasible. The recycled sand is washed and separated using Renewi’s advanced recycling technology and then used for new concrete columns - from rubble to product. The materials remain suitable for future recycling, even after the columns reach the end of their service life.

Towards higher levels of circularity

The Netherlands is currently operating mainly at a level where only gravel is recovered from concrete waste. Renewi is among the few companies recovering both gravel and sand for new concrete. The company continues to work on innovations to take concrete recycling to an even higher level.

Procurement must reward circularity

“The technology is proven, but the market now needs to follow,” says Jan-Pedro Vis, Director of Circular Materials at Renewi. “When clients require contractors to work in a circular manner – from demolition to the use of circular raw materials – we can truly scale up towards a circular economy.”

“The chain can only be fully closed when clients structurally include circularity in their award criteria,” emphasises Jan Wagner, Managing Director at Holcim Bouw & Infra Nederland. “Our partnership with Renewi shows how chain partners strengthen one another. By working together on solutions that are both technically sound and certified, we move closer to our ambition of 100% circularity by 2035.”

The innovative concrete columns demonstrate that technology, quality and collaboration bring us a step closer to a circular concrete chain.