New cooperative research project Min-Loop

The Institute of Building and Construction Materials is starting a new cooperative research project funded by the Ptj.


As part of the funding measure from the BMBF “REMIN – Ressource Efficient Recycling Management – Construction and Mineral Material Cycles” the WiB and its partners started the project by the name of “Substitution of polysterene-based rigid foams with cement-bound mineral foam made from recycled crushed concrete sand in sandwich hybrid ceilings for purely mineral material cycles in building construction”.

By participating in the cooperative research project Min-Loop within the framework of the REMIN funding measure by the BMBF, the WiB contributes to the development of recyclable components.

Sandwich hybrid ceilings add a major contribution to the reduction of component dead loads and resource-efficient material use. However, due to the use of polysterene as a displacement body, complete recycling and thus closure of the material cycle has not yet been achieved.

In the cirular economy, great importance is attached to the production of components with recycled materials. Resource-efficient concrete (R-concrete) is subject to the DAfStb guidlines. Here, however, the use of crushed sands (d < 2 mm) from concrete recycling is currently excluded. The high proportion of fines can have negative effects on the freeze-thaw resistance and fresh concrete properties of normal concrete. As a result, these sands (approx. 20 % to 30 % of the crushed concrete mass) are landfilled. With increasing shortage of materials and increase in demand for concrete, this is a devastating signal.

The use of recycled crushed concrete sands in mineralised foam as a component of a hybrid construction element offers economic and ecological advantages without the disadvantages mentioned and without having to follow the mentioned guideline. The central objective of the Min-Loop project is the generation of an almost complete mineral material cycle for hybrid ceiling elements by substitution of polystyrene foam with mineral substitute building materials and the use of crushed concrete sands.

Funded by PtJ as part of the BMBF funding measure REMIN.


Prof. Eddie Koenders

Prof. Dr.-Ing. Albrecht Gilka-Bötzow

M.Sc. Conrad Ballschmiede