Sustainable binders and concretes derived from selectively ground concrete waste
Luise Wedekind, Alexander Schnell, Horst‐Michael Ludwig, Marcel Keilholz, Martin ReformatAbstract
In the RESELEKT research project, the resource‐efficient reuse of waste concrete is investigated using selective comminution. The aim is to develop climate‐friendly binders and concretes that utilize all fractions of recycled concrete, from coarse aggregates to recycled fines. The project was carried out by Bauhaus‐University Weimar, LOESCHE GmbH, and HABAU Deutschland GmbH from 2023 to 2025. Selective comminution is based on the differing strengths of concrete constituents. Using a vertical roller mill, these differences can be exploited to obtain high‐purity RC aggregates, RC sand, and RC fines. The combined process of comminution, air classification, and drying enables gentle treatment and precise fractionation. The recycled fractions can be reused as raw materials for new binders and concretes. RC aggregates and RC sands showed properties comparable to natural materials. Recycled concrete fines can serve as a secondary binder, with studies indicating cement replacement rates of up to 30 wt.%. The project demonstrates the potential of recycled concrete to conserve resources, reduce CO 2 emissions, and support circular construction.