Switzerland gets going with the recycling of construction waste

Between 70 and 80 million tonnes of construction materials are needed every year throughout Switzerland. Around 10 percent of this requirement – 9.3 million tonnes – is met by recycled building materials. However, considerable potential still exists in this area. The advantages are obvious.

Construction waste is is mainly comprised of materials like concrete, sand, asphalt, tile and roof tile, pottery, porcelain.

Anna Birkenmeier, 17.03.2017

Large amounts of construction waste are generated by the demolition of buildings and by road repair and maintenance. Besides excavation material, at over 15 million tonnes per year, mineral construction waste is by far the biggest waste stream generated in Switzerland. It is mainly comprised of materials like concrete, sand, asphalt and masonry. For many years this construction waste was deposited in landfills, despite the fact that it could be of further use to the construction industry with its high levels of resource consumption. Hence the closure of material cycles and recycling clearly makes sense in this sector.

“We should have reached a far more advanced level with regard to the recycling of construction material,” says Laurent Audergon, CEO of arv Baustoffrecycling Schweiz. “The SIA 430 standard ‘Disposal of construction waste’ entered into force in 1994 with the aim of making recycling and separate disposal of construction waste the norm. Ecological specifications for the recovery of mineral construction waste, the associated quality requirements and possible applications were also defined in the guidelines published by the FOEN in 2006. Despite the fact that the necessary technical and normative conditions have long been established, there have been very few developments in this area over the last 20 years.” Audergon firmly believes that the new Federal Waste Ordinance “will help here”. The association led by him is composed of companies – and their representative associations – which extract secondary raw materials and construction materials, process such materials, and carry out projects involving contaminated construction waste from buildings and the ground.

Demolition of a building. Concrete and tile are the main recycled minerals.

Fewer environmental impacts

The recycling of construction waste has a lot of advantages to offer: “First, the recovery of mineral construction waste conserves natural raw materials. Second, it means that already scarce landfill space is used more sparingly,” says David Hiltbrunner from the Waste and Resources Division at the Federal Office for the Environment (FOEN). According to the FOEN, mineral construction waste should be recycled rather than deposited in landfills, as the recycling of waste has less of an impact on the environment than other forms of disposal or the manufacture of new products.

“Another ecological advantage is the protection of nature and the landscape thanks to the considerable reduction in the use of land for the extraction of materials and for landfills,” says Hiltbrunner. The aim of recycling is to use the materials in a way that takes their material properties into account. “In reality, recycled products are often used in technically less sophisticated areas, for example as road bed and infill material, that is wherever the quality requirements are not very high. The way in which the recycled material is processed is always crucial,” says Hiltbrunner.

Processing makes all the difference

Recycled construction materials are used for different applications, depending on how they are processed. Some cantons have taken up the cause of promoting construction material recycling. The canton of Zurich, for example, is strongly committed to the processing of concrete rubble and supports the use of recycled construction materials, and the city of Zurich constructs a large number of its buildings using recycled concrete. 

Recycled construction waste is used for building streets.

“The use of recycled concrete as structural concrete, that is in the construction of buildings, was inconceivable until recently. But the situation has changed radically in recent years,” says Stefan Eberhard, Vice CEO of the company Eberhard Bau AG. In its Ebirec construction materials recycling centre in Rümlang, the company produces among other things structural concrete made entirely from recycled aggregates. “What is crucial in the production of high-quality concrete from recycled materials is a comprehensive knowledge of the processing and concrete technology,”  explains Eberhard. This is the only way that we can go beyond the simple “addition” of demolition material, as is the case with “second-class” recycling, and produce high-quality recycled structural concrete.

The public sector leads the way

The canton of Solothurn also aims to recycle over 90 percent of its mineral construction waste in the future. The basis for this is provided by the canton’s new construction material recycling strategy which contains provisions for the consistent use of recycled construction materials for public buildings and the provision of more information about them. Thilo Arlt from the Canton of Solothurn Office for the Environment explains: “In the canton of Solothurn, around 85 percent of the mineral demolition material produced was recycled in recent years. There is clear potential for increasing this.”  

After being sort, mineral construction waste is chopped.

“Recycling still has an image problem”

Despite this positive development, Hiltbrunner also sees some challenges ahead for the recovery and recycling of construction materials: “Recycled construction materials still have an image problem. If concrete produced from primary material costs the same as recycled material, many people still opt for the primary material.” Moreover, the recycling of construction material is hardly worthwhile when gravel prices are low. The production of concrete in Switzerland today requires around 33 million tonnes of gravel annually – 2 million of this comes from recycling and the rest involves primary consumption.

So how can we improve the acceptance of recycled construction materials? “We have to improve the image of recycling products. From a purely qualitative perspective, recycled construction material is not at all inferior. Its production and quality control are subject to the same generally applicable and strict standards,” says Thilo Arlt. It is important to persuade planners, engineers, architects and clients of the importance of the material-cycle concept and of the functional use of high-quality recycled construction materials.

Laurent Audergon has the following to say in this regard: “The engineering and construction sector is very conservative and has blocked many developments up to now. We must educate architects and engineers and make them aware that the consistent use of recycled materials pays off for their clients, the environment and society.”

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Last modification 17.03.2017

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