A German research organisation has developed a way to reuse the country’s 5Mt of building rubble left over from construction each year.
Following a three-year long €3.3M (£2.87M) research project, the Fraunhofer Institute for Building Physics has developed the solution for dealing with fine-grained building rubble.
Called the BauCycle process, it separates the various components using an opto-pneumatic detector that enables fine fractions to be separated on the basis of the colour, brightness and chemical composition of the particles; it is even capable of distinguishing sulphates from silicates.
Under ideal conditions the BauCycle can sort through of 1.5 metric tonnes per hour.
The ultimate aim of the project is to transform the mix of minerals within construction waste into a sustainable resource and demonstrate potential applications of reusing the materials regained in construction.
The materials separated can used in the production of aerated concrete, a light building material with good thermal insulation properties that is suitable for small structures such as two-storey homes.
The project also found that mixing bricks and components from the recovered concrete can be used to make geopolymers, a cement-free building material that is strong and acid-resistant, much like concrete but with a much lower carbon footprint.
The German-based Fraunhofer institute, which has 72 campuses spread throughout Germany, will present its full findings at the BAU 2019 trade fair in Munich next year.
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