Frequently asked questions

Yes. Liberated Concrete is certified for both quality and sustainability and complies with applicable laws and regulations. It performs on a par with traditional concrete — and sometimes better. Would you like to see the specific certifications? Please get in touch.

Liberated Concrete is made up of three Smart Liberated Materials: Freement® (recovered cement, available in fine and coarse), Freesand® (circular sand) and Freegravel® (circular gravel). Each of these raw materials is technically comparable to primary materials.

The material is suitable for all applications. Think high-rise, tunnels, viaducts, bridges, prefab and other concrete structures where traditional concrete is normally used. Not sure whether it is right for your project? Get in touch — we are happy to advise.

Compared with traditional concrete, Liberated Concrete achieves a CO₂ reduction (GWP) of 63% to 80%, depending on the reference concrete. The environmental cost indicator (MKI) is also significantly lower. We have an EPD for each mix in accordance with European standard EN 15804, available on request via our contact form.

Yes. Thanks to our EPDs and certifications, Liberated Concrete can be clearly substantiated in tenders where circularity or CO₂ reduction counts. We are happy to help with the right documentation. The earlier you involve us, the more value we can create together. Please get in touch.

The Smart Liberator is our own machine that breaks down concrete rubble through a process of crushing, sieving and refining into its original components: sand, gravel and cement. Where traditional crushers produce roughly graded aggregate, the Smart Liberator recovers the raw materials at the level of the original particle packing.

The concrete rubble is first analysed for composition. We then process it in the Smart Liberator, which liberates the concrete into sand, gravel and cement. These raw materials are refined and used in the production of Liberated Concrete. Nothing disappears from the concrete chain.

We start well before demolition. Through surveys, XRF analyses and microscopic examination, we map the composition of the concrete to be demolished. This allows us to know exactly what we are taking in, harvest with precision and maintain quality throughout the entire chain.

These are our three circular raw materials, together known as Smart Liberated Materials. Freesand is circular sand recovered from demolition rubble, Freegravel is circular gravel liberated from existing concrete, and Freement is circular cement that replaces traditional Portland cement. All three are technically comparable to primary raw materials.

We aim to return all delivered concrete to reusable raw materials as fully as possible. By conducting thorough research into the composition in advance, we maximise the yield of every delivery. Get in touch for a tailored estimate.

SL Materials grew out of the Rutte Group, an Amsterdam family business that began in 1965 as a transporter of concrete paving materials. In 2002, we produced the first concrete units made from 100% recycled material. In 2016, we started working with Koos Schenk to scale his Smart Crushing technology to industrial level. In 2018, we launched Freement, the first circular cement from our own production. In 2026, we launched SL Materials as an independent brand.

The SL stands for Smart Liberated, a reference to our core method: liberating high-quality raw materials from existing concrete using smart technology. The name is also a tribute to Koos Schenk, who conceived the Smart Liberator.

SL Materials grew out of the Rutte Group. We work with a team of skilled professionals, scientists and entrepreneurs who share the conviction that circular concrete should be the norm. For specific contacts, please visit our contact page.

SL Materials grew out of the Rutte Group, an Amsterdam family business with more than sixty years of experience in transport and concrete materials. The knowledge, network and infrastructure of the Rutte Group form the foundation on which SL Materials has been built.

To make circular concrete the standard in construction — as an obvious choice. We are working towards a sector in which every demolished building becomes raw material for the next one. We are doing that today, together with demolition companies, contractors, architects and scientists.

Liberated Concrete is certified for quality and circularity, in line with applicable concrete standards. We produce an EPD for each product in accordance with European standard EN 15804. Would you like the full list or a specific EPD? Please get in touch.

We produce a life cycle analysis (LCA) for all our products in accordance with EN 15804. This covers the environmental cost indicator (MKI), greenhouse gas emissions (GWP) and circularity. Results are independently verified and validated. An EPD is available for each product.

No. Liberated Concrete performs on a par with traditional concrete — sometimes better. The difference lies in the origin of the raw materials, not in quality. Our products meet the same standards and are produced in accordance with applicable laws and regulations.

The proportion of recycled raw materials in Liberated Concrete is high, but varies by mix and application. We are continually working to increase this proportion. Would you like precise figures for a specific product or project? Request our EPD or get in touch.

We measure the full life cycle of our products, including the production process. Our factory in Zaandam runs on solar energy from the rooftop solar installation. The net CO₂ reduction of Liberated Concrete compared with traditional concrete is between 63% and 80%, even when the production process is taken into account.

We work with TU Delft, amongst others. We also have collaborations with other academic partners in the field of circular concrete materials and production methods. We actively share knowledge through publications.

These are three methods we use to map the composition of incoming concrete rubble. Thin sections and petrography provide a microscopic view of how cement paste, sand and gravel bond at the micron level. XRF analyses the chemical composition. These insights help us refine our process and monitor the quality of the output.

The Smart Refiner is the next step in our production chain, aimed at further refining the liberated raw materials. We are actively working on this in our lab, in collaboration with academic partners.

Our factory is also our laboratory. Insights from research are fed back directly into production. What we learn in the lab, we apply on the factory floor as quickly as possible.

We are open to collaboration with researchers and students, particularly in the areas of circular concrete materials, cement chemistry and production methods. Please get in touch to discuss the possibilities.

We accept concrete rubble from demolition projects. The quality and composition of the concrete partly determine what we can do with it. We map this together through preliminary research using X-ray analysis and microscopic examination. Get in touch to discuss whether your material is suitable.

We assess that together, preferably before demolition begins. Through survey and laboratory research, we determine the composition and quality. The earlier you get in touch, the more we can optimise together.

We start with a conversation about your project: what is being demolished, when and how much. We then plan the preliminary research and agree on delivery arrangements. Fill in the contact form or call us directly — we will get back to you within one working day.

The concrete rubble goes into the Smart Liberator, where we liberate it into sand, gravel and cement. These raw materials are refined and processed into Liberated Concrete. Your demolition concrete becomes the foundation for new circular concrete.

Please get in touch to discuss the possibilities. We are happy to explore options, including for smaller or unusual batches.

Ordering starts with a conversation. Fill in the contact form on this page or call us. Tell us about your project: type of concrete, quantity, schedule and any sustainability or circularity requirements. We will get back to you within one working day.

Lead times and minimum quantities depend on the type of project and the mix required. We are happy to discuss this on a project-by-project basis. Get in touch for a concrete indication.

Yes, that is possible. Please get in touch with our team to discuss the options.

We can provide you with EPDs, certifications and technical specifications for each product. These documents are generally sufficient for specification in a bill of quantities or tender. Get in touch and we will make sure you have the right documentation.

Fill in the contact form on the order page or send an email to our team. We respond within one working day.