Recycling construction foams

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Recycled plastic waste- Photo: REPOLYUSE

The REPOLYUSE project is pioneering solutions to recycle plastic waste from the refrigeration or construction industry, car seats and manufacturing waste from the automotive industry and lock it back into new construction materials. Its main target are polyurethane foams, commonly used for insulation.

These plastic compounds are challenging to extract from building rubble, and even more challenging to recycle into usable materials.

More than 3.5 million tonnes of polyurethane are used in Europe each year. About 20% of this material ends up as waste, the vast majority of which (c. 460 000 tonnes per year) goes to landfill. Using polyurethane waste to replace gypsum used in insulation material would save energy and water as well as reducing the amount of gypsum that needs to be quarried (currently some 1 million tonnes per year).

The REPOLYUSE process

“We treat the foams, crushing and mixing them with gypsum,” says scientific project manager Sara Gutiérrez at the University of Burgos in Spain. The recycled foams can also be mixed with other construction materials like cement, mortar and bituminous asphalt. “Not only does this save natural resources, it can also lighten construction materials and improve their physical properties, making buildings lighter and improving their energy efficiency through the use of this new material.” Ms Gutiérrez notes that the carbon footprint of the buildings is also reduced.  

The University of Burgos built the first prototype construction materials incorporating polyurethane earlier this year and have since been running thermal and physico-chemical tests on them. The prototypes are being deployed in three demonstration sites in Spain and the UK to field test their impact on temperature, humidity and sound insulation inside real buildings. “As of January 2019, we will launch larger scale production,” says Ms Gutiérrez.

100-year lifespan

One environmental advantage of incorporating polyurethane into construction materials is that buildings can store them for up to 100 years and offer the plastic a useful second life. After this period, Ms Gutiérrez says that the construction materials can sometimes be reused directly or broken down using established techniques to reuse their plastic in further recycling.

“We already have technology for separating 100% of the polyurethane from gypsum and reusing it in new construction products,” says Ms Gutiérrez. Initial tests at lab scale suggest that these processes gradually reduce the mechanical resistance and thermal properties of the plastic. Nonetheless, project partners are convinced that the recycled material could be used profitably as an inert polymer in non-load bearing applications such as insulation materials or pipes.

More examples of how LIFE is helping to improve plastics recycling can be found in the LIFE and the EU Plastics Strategy [pdf] brochure.

 

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