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Project aims to transform construction waste into new building materials

Published: 13.01.23

In collaboration with the manufacturers Troldtekt and Komproment, and the waste collector RGS Nordic, DBI is aiming to develop pilot plants over the next three years that will use construction waste to produce geopolymer binders. This can replace cement in new building materials.

Production of cement requires a lot of energy, mostly due to the calcination of limestone -at 1,400–1,500 degrees. If the total CO2emissions from the construction industry are to be reduced – and they must be – it will be necessary to identify alternatives to traditional cement. One solution could be geopolymers, which can function much in the same way as traditional cement. For several years, DBI has therefore been involved in the development of geopolymer applications for the building industry.

“Simply put: Geopolymers consist of an aluminosilicate material (precursor) to which an alkaline liquid is added (activator), which ultimately results in solidification. Precursors can be composed of pre-treated waste-materials such as brick, glass and slate. This means that there’s less need for virgin materials,” says Corbin Entz, Research Consultant at DBI, elaborating:

“We divert a waste fraction from landfill and use it in building materials such as Komproment’s facade tiles and Troldtekt’s acoustic panels. The geopolymer products can be produced without exceeding 80 degrees and are much more CO2-friendly.”

Cement from waste?

Work with geopolymers has been under way at DBI for some time.

“We’ve produced prototypes of facade tiles in collaboration with Komproment and acoustic panels in collaboration with Troldtekt, replacing traditional cement with geopolymer in both products. But the potential for geopolymers is far greater. It can potentially replace traditional cement in a whole host of products,” says Kasper Prochownik, Research Consultant at DBI.

The two projects have paved the way for the latest step in this development. In collaboration with the two manufacturers and the waste collector RGS Nordic, DBI is being supported by MUDP (Environmental Technology Development and Demonstration Programme) to develop the production of building materials based on geopolymers from prototype level to small-scale production. The project is called Re:Source, a name that refers to the fact that it involves the reuse of waste from construction.

“The use of geopolymer in the construction industry is very limited, even though it’s not a new technology. Waste fractions have been used as precursor for geopolymer by others, but not on the scale we’re aiming for. In Re:Source we’re upcycling Denmark’s largest waste source – construction and demolition waste. One part of the challenge is that there’s not yet an established value chain between waste and new products, so this is also something we need to look at,” says Corbin Entz.

Material properties must be in place

Re:Source will run until summer 2025, and the project is being supported by MUDP under the Danish Ministry of Environment to the order of DKK 6.5 million. This funding is crucial to enable the partners in the project to establish an actual production process to produce a certain volume of geopolymer binder per week. Even though it will be a small production setup, the logistics around the process still require the right physical conditions, such as warehouse, machinery, and staffing. The waste will require some degree of pretreatment before the geopolymer binder can be produced, for inclusion in the production of new façade tiles and acoustic panels. This will all be done in the new pilot plant.

“We conduct indicative tests of prototype products based on a wide range of parameters, because there are many material properties that must be in place before it makes sense to proceed with the production of the product. Fire is one of them, but there are also others, such as moisture properties and physical strength. If the results are comparable with Komproment’s and Troldtekt’s current products, the products will be tested at an accredited test institute,” says Kasper Prochownik.

“We have a goal of using the products we manufacture for demo projects in the construction industry, which is important to get attention of the whole construction industry. Hopefully, Re:Source can pave the way for manufacturers to start incorporating geopolymer based products into their portfolio alongside their regular production,” says Corbin Entz.

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Re:Source is a MUDP project (Environmental Technology Development and Demonstration Programme), which is supported by MUDP under the Danish Ministry of Environment to the order of DKK 6.5 million. The project involves DBI, the two producers Komproment and Troldtekt, the waste collector RGS Nordic as well as DTU. The purpose of the project is to establish a mini-scale production process for geopolymer based products. The products are to be used in demonstration projects in the construction industry. Re:Source will run until summer 2025.


Frederik Kruse
Project Manager

+45 50 80 65 33