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CONCRETE TECHNOLOGY60 CPI %u2013 Concrete Plant International %u2013 2 | 2026 www.cpi-worldwide.comSince March 2023, an Austrian research consortium has been working on the %u201cBitKOIN%u201d project to develop a synthetic blast furnace slag substitute (slag 2.0) from mineral wool waste. The aim is to process this waste, together with additional complementary secondary raw materials, into a binder component. This has already been successfully achieved several times at pilot-plant scale. Initial test concretes have also been produced, and their performance has exceeded expectations.BitKOIN is funded by the Austrian Research Promotion Agency (FFG) and is led by Montanuniversit%u00e4t Leoben. In addition to Rohrdorfer Umwelttechnik and Montanuniversit%u00e4t Leoben, the project consortium includes Graz University of Technology, Porr Umwelttechnik GmbH, Saint-Gobain Austria GmbH, and Holcim CTEC GmbH.Extensive cleaning and conditioningIn order to process mineral wool waste so that it can replace blast furnace slag, several steps are required. First, the material is prepared and pre-crushed in a shredding facility. This is followed by conditioning with a calcium-rich secondary raw material. The treated waste is then melted, granulated, ground, and used in place of conventional blast furnace slag for cement production.During the pilot trials, these preparatory steps were carried out by the project partners as follows: Montanuniversit%u00e4t Leoben (sample preparation and melting trials), Graz University of Technology (construction material testing), PORR Umwelttechnik GmbH (industrial shredding and conditioning), and Holcim CTEC GmbH (production of the cement types CEM II/B-M and CEM II/C-M).Promising interim resultsStandard concrete of strength class B2 was produced from the newly developed cements. These concretes underwent extensive testing at the central laboratory of the Rohrdorfer Group in Krieglach, including evaluations of compressive strength and resistance to carbonation. Some of the B2 concretes produced during the pilot trials outperformed the reference concrete based on conventional blast furnace slag.Research Project BitKOIN: Initial concrete tests exceed expectationsRohrdorfer Umwelttechnik GmbH, 8600 Bruck an der Mur, AustriaMineral wool waste prior to processing. Testing carbonation resistance on concrete prisms.