Projects / 10/16/2024

Old structures and new bold projects

Innovative recycling in concrete production: a Danish entrepreneur’s circular approach

In the scenic town of Vordingborg, in Denmark, entrepreneur Peter Halkvist has launched a pioneering concrete and recycling business. By combining two waste streams, crushed ceramic tiles and asphalt, he creates sustainable concrete blocks, reducing both environmental impact and raw material costs. With the help of RE-CON AGG 100, aMapei admixture for concrete, Halkvist has optimized his production process, cutting down on water and cement usage while improving workability. This initiative exemplifies the growing trend toward circular systems in the construction industry, with a focus on sustainability.

A Danish start-up entrepreneur uses Re-Con AGG 100 to save cement in concrete

In the idyllic landscape of southern Sjælland (Denmark), RE-CON line newsletter visited the town of Vordingborg to talk with Peter Halkvist about his start-up company Halkvist betong. We turned south after the Øresound bridge crossing and drove south towards the historic town of Vordingborg, where the castle ruins still host Scandinavia’s best preserved medieval tower. A remnant from historic times when Danish kings and queens built impressive fortresses as shelter in times of war and unrest. The landscape bears many signs of Viking settlements. It is a nice contrast to find ourselves in modern times, where bridges and tunnels are being constructed to improve trade routes and connect the countries of Germany, Denmark and Sweden in an enormous infrastructure initiative that will shorten travel times for goods and people in a region hosting close to 7 million people as Malmö and Copenhagen’s metropolitan areas will be linked with the States of Schleswig-Holstein and Mecklenburg-Vorpommern in Northern Germany.

One of the two waste streams used at Halkvist betong is made of crushed ceramic tiles.

A true circular system to make concrete blocks

It is in idyllic, yet dynamic Vordingborg that Peter Halkvist started his concrete and recycling business. “My vision is to create a true circular system of material flows and make concrete from recycled raw materials”, Peter explains. “I have managed to combine two waste streams, crushed ceramic tiles and crushed asphalt into a raw material that I use for block concrete. The two waste streams would otherwise have ended up mostly in landfill. So, to use them in new concrete saves both the environment and cost of raw material. There is great potential to move into larger concrete structures in suitable applications, like slabs or floors.”.

RE-CON AGG 100 admixture is crucial in the production of concrete blocks at Halkvist betong.

Peter walks us through his production line from the receiving of crushed ceramics and asphalt, through the concrete mixing plant and finally the casting of the blocks. He tells us about how he contacted Jean Steffensen from Mapei Denmark for assistance in the concrete mix design. “The raw material is very demanding and absorptive: it was hard to keep the workability for the time I needed in the beginning. Mapei and Jean suggested to use RE-CON AGG 100 to mitigate the absorption, and it really helped”, Peter continues. “The combination of pre-wetting the raw material and using RE-CON AGG 100 helped me to cut down drastically on the water in the mix design. I also cut down my cement usage by about 50 kg per m³ of concrete. It’s a true win-win, both for the CO₂ footprint and the cost of production”,

Peter concludes. “To do the same task that the RE-CON AGG 100 is doing for me, I would have to use around three times as much conventional superplastizicer. RE-CON AGG 100 was definitely a game changer for me”.

Jean Steffensen said: “At Mapei Denmark we see a growing interest for sustainability and material circularity. Halkvist Betong is a perfect example of implementation of solutions that we will see much more of in the concrete industry in the coming years. Mapei have also supplied products for ongoing major projects such as Storstrømsbroen and the Fehmarn link.”