Holistic Innovative Solutions for an Efficient Recycling and Recovery of Valuable Raw Materials from Complex Construction and Demolition Waste (HISER)

 

HISER
higher recovery of raw materials from Construction and Demolition Waste
HISER
higher recovery of raw materials from Construction and Demolition Waste

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Demolition case study: business-as-usual in Flanders

In order to assess the economic and environmental performance of the developed HISER solutions, a clear reference scenario has to be described. Therefore, VCB and VITO followed up a demolition work in Flanders. The demolition process followed the current practices and the HISER partners did not interfere in the process.


In Flanders, selective demolition is current practice. This is mainly driven by economic reasons (high landfill fees, lower gate fees at recycling plants for materials that are selectively removed). This current selective demolition practice aims at the selective removal of hazardous materials (e.g. asbestos) and materials with a high value (e.g. metals). Special attention goes to the production of a qualitative stony fraction that is easy to process into recycled aggregates.
For buildings >1000 m³ with a (partially) non-residential function, a pre-demolition inventory is mandatory. Furthermore, every building requires an asbestos inventory prior to demolition. This asbestos inventory can be integrated in the pre-demolition inventory. A pre-demolition inventory should contain an overview of all hazardous and non-hazardous materials that are available in the building, together with their EURAL-code, estimated quantity, location and appearance. The inventory - when drawn up correctly - is a useful tool for planning a demolition work. During the case study, it became clear that the pre-demolition inventory for this building lacked several materials (mostly enclosed insulation materials).
As a first step in the demolition process, the building was manually stripped from hazardous materials (e.g. asbestos, fluorescent lamps) and materials that were easy to remove (e.g. furniture, suspended ceilings). Asbestos (e.g. roof tiles, ventilation caps, fuses) was removed by a specialized contractor (Figure 1). The non-hazardous materials were selectively removed and divided in three fractions: metals, wood and a residual fraction (e.g. plastics, thermal insulation) (Figure 2).

 figure1

Figure 1: Asbestos applications (left, middle) and asbestos removal (right). 

 figure2

Figure 2: Obtained non-hazardous fractions during dismantling: fltr wood, metals and residual fraction.

After the dismantling phase, the structural building was demolished using bulldozers and hydraulic excavators (equipped with sorting grapples and concrete crushers). This phase was hampered by the presence of thermal insulation materials that were difficult to remove. For example, suspended ceilings were filled with expanded polystyrene (EPS) beads and foam insulation was stuck to the walls and ceilings (Figure 3). During the structural demolition phase, materials were also sorted on site in different fractions: stony material (Figure 4), steel (concrete reinforcement), aluminium (window frames), wood and a residual fraction (e.g. roofing, thermal insulation). The stony material was subdivided in the following fractions: a pure concrete fraction (e.g. foundation, concrete slabs), a mixed stony fraction (e.g. walls) and a reusable brick fraction. This latter fraction consisted of high-grade façade bricks with lime mortar (easily removable).

figure3 

Figure 3: Foam insulation before and after removal (left & middle), EPS insulation.

 Figure4

Figure 4: Concrete fraction before removal of reinforcement (front), mixed stony fraction (back).

 

The project has received funding from the European Union's  Horizon 2020 research and innovation program under grant agreement No 642085.

 

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