Cement ensures durability and strength

While the wood contributes breathability and flexibility, the cement adds strength and durability to Troldtekt cement-bonded wood wool.

By using cement as the binder, the acoustic panels do not weaken or age in the same way as, for example, metal or wooden surfaces. This ensures that Troldtekt acoustic panels have a long lifespan of at least 50-70 years, and can often ‘live on’ when a building is refurbished or repurposed. This makes it possible to save resources and CO₂ for the production of new building materials.

Due to their strength and durability, Troldtekt acoustic panels are also suitable for particularly demanding environments – for example swimming pools with chlorine fumes and high humidity levels.

It is also the cement that makes Troldtekt acoustic panels fireproof – without the use of harmful chemicals.

A significantly lower carbon footprint with FUTURECEM

Troldtekt has developed a Cradle to Cradle-certified acoustic panel in which the cement has been replaced with the new low-CO₂cement type FUTURECEM^TM. FUTURECEM is a patented type of cement from Aalborg Portland, which synergises calcined clay with lime filler. In this way, much of the fired clinker in the cement can be replaced, and the result is a 30 per cent lower carbon footprint from the cement.

Troldtekt acoustic panels based on FUTURECEM absorb more CO₂ than they emit during production (phases A1-A3 in an environmental product declaration (EPD)). In other words, they have a negative carbon footprint in these phases. This is because the wood in the panels absorbs CO₂ when the trees are growing in the Danish forests. At the same time, production takes place at Troldtekt’s factory, which uses 97.7 per cent renewable energy. Together, this makes it possible for the net carbon footprint from raw materials, raw material transport and manufacturing to be less than zero.

The following shows how much CO₂ is saved by replacing the grey cement in a Troldtekt acoustic panel with FUTURECEM cement in EPD phases A1-A3 (production):

	Troldtekt based on FUTURECEM	Troldtekt based on grey cement
Carbon footprint per m² of unpainted Troldtekt acoustic panel (EPD phases A1-A3)	-1.4 kg/m²	0.677 kg/m²
Carbon footprint per m² of painted Troldtekt acoustic panel (EPD phases A1-A3)	-1.0 kg/m²	1.13 kg/m²

The carbon footprint for the entire life cycle of a Troldtekt acoustic panel depends on what happens to the panel after the end of its service life (EPD phase C4). If it is incinerated, the stored CO₂ in the wood is released, but various forms of recycling can help to minimise emissions.

In fact, offcuts from Troldtekt’s production are already being used as a raw material in new cement – and a new pilot project will establish whether this particular scheme can be scaled up to also include cement-bonded wood wool waste from the demolition of buildings.

Replacing grey and white cement

The different types of Troldtekt acoustic panels contain either grey or white cement. To begin with, Troldtekt has introduced acoustic panels in which FUTURECEM replaces the grey standard cement. The solutions in Troldtekt’s award-winning design series will also be available based on FUTURECEM.

In the long run, the ambition is for FUTURECEM to also replace white cement. This will result in an even greater CO₂ reduction in phases A1-A3 – from 1.73 kg/m² today to -1.0 kg/m² with FUTURECEM. Compared to standard grey cement, the potential CO₂ saving is even greater for white cement.

The acoustic and fire-protective properties of Troldtekt acoustic panels based on FUTURECEM are the same as for Troldtekt panels manufactured using ordinary cement. The panels’ inherent strength is also preserved, while they have a slightly warmer look.

Absorbs CO₂ during use

Troldtekt only uses cement from Aalborg Portland, which extracts the raw materials from the Danish underground with minimal environmental impact.

When we produce the acoustic panels, the cement in the cement-bonded wood wool starts to absorb CO₂ gradually as it sets. The cement layer that surrounds the wood wool in a Troldtekt acoustic panel is very thin and therefore has a large surface area. Consequently, all the cement can more easily carbonise – i.e. bind CO₂ – during the lifespan of the panel. In fact, a Troldtekt acoustic panel is able to naturally absorb and store more CO₂ than solid concrete.

Towards an even lower carbon footprint

The cement accounts for almost the entire carbon footprint of a Troldtekt acoustic panel. Therefore, our ambition is to further reduce the cement’s footprint, while at the same time exploring whether it is possible to use binders other than cement.

Aalborg Portland is collaborating with the Danish government on realising extremely ambitious goals for reducing its CO₂ emissions. Specifically, the company has committed to reducing emissions by 600,000 tonnes in order to support Denmark’s goal of reducing GHG emissions by 70 per cent by 2050. The target is a 30 per cent reduction by 2030.

In addition to launching greener cement products such as FUTURECEM™, Aalborg aims to achieve its goals by working with energy-efficiency improvements, by phasing out fossil fuels, through carbon capture, through the increased use of alternative or carbon-neutral fuels and by supplying carbon-neutral district heating to over 75,000 households.

Investigating alternative binders

We are also investigating binders that could be a possible alternative to cement. One example is geopolymers, which are not based on lime, but instead on silica/alumina compounds, which are found in ash from biomass, for example.

In collaboration with the Danish Institute of Fire and Security Technology (DBI) and with the support of Innovation Fund Denmark, we are looking into whether it is possible to use for example geopolymers as a raw material in Troldtekt acoustic panels and what it would require to do so.