Towards more sustainable concrete

Working together on a more sustainable construction process is so our thing! The signing of the Flemish Concrete Agreement fits perfectly into that picture.

Entire sector involved

Hilde Carens: “The agreement is the result of two years of intensive collaboration with the entire concrete sector, from concrete producers and attestation companies to demolition companies. Concrete is everywhere in the construction sector and thus has a huge environmental footprint. In recent years, we looked at how to use concrete more sustainably in the construction process.”

We took a closer look at the whole chain, from production to demolition. Hilde: “In production, for example, it's cement that has a huge environmental footprint. We started looking at whether we could replace cement or organise production in an environmentally-friendlier way. The actual application of concrete in buildings – which is very important for us – was also discussed. Do you make easily reusable elements? Or a product that allows high-grade recycling?”

Supply and demand

Hilde “As members of both the steering committee and the transition group, we helped to ensure the ambitions in the agreement are very high. By signing, we've undertaken to put that theory into practice. As property developer, we found that a sustainable concrete offer is practically non-existent. Concrete producers, on the other hand, blame the low demand, which makes it unprofitable to change their production process. This joint commitment means we can count on a solid supply, and producers can be sure of sufficient demand.”

Specific actions

This seamlessly brings us to our first initiative. Hilde: “The standard in specifications is between 20 and 30% recycled material in concrete, depending on the application. This 20 or 30% is now an essential condition in our tender specifications. In other words, what the agreement prescribes as a maximum, we now use as a minimum.”

And it doesn't end there of course. We also look into what is possible earlier on in the process. Hilde: “Can we prefabricate certain elements instead of using cast concrete? We analyse that question with our designers. It's significant that in the design phase we also immediately look into how we can dismantle those elements later. That way, we can recycle them - internally or externally.”

We also conduct a complete audit of a construction project to see how we can make our concrete mix as sustainable as possible for each application. Hilde: “For example, we examine whether and how we can (partially) replace the cement in the mixture for some applications. For that research, we just received official approval for a joint grant project led by Buildwise - the Living Lab Circular Concrete. We incorporate the lessons learned into standards for future projects.”

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