ÖBB is testing recycled concrete: development of new acoustic barrier with Kirchdorfer Concrete Solutions

Concrete has many good properties: it is robust, has a high load-bearing capacity and is very resistant to moisture, high heat and severe cold. In addition, it provides outstanding sound insulation. Its environmental balance, however, is not without controversy: especially the manufacture of cement requires high temperatures and, accordingly, emits high amounts of CO₂. ÖBB-Infrastruktur is here breaking new grounds: on a track section of the Western Rail Line near Linz/Hörsching/Traun, Austria, over a length of 100 running meters, acoustic barriers are used whose proportion of recycled concrete lies at already around 30 %. This means that nearly one-third of the concrete bearing course of the acoustic barriers consists of recycled aggregate and, therefore, , that old concrete is sustainably reused. A first so-called operational test for the new acoustic barriers started in April of 2024 under the ringing title “Test section acoustic barrier of recycled concrete.”

Manufactured by MABA Fertigteilindustrie

The innovative walls are manufactured by the company MABA Fertigteilindustrie GmbH, which is part of Kirchdorfer Concrete Solutions. The production and development costs were assumed by MABA, while ÖBB-Infrastruktur AG conducts the monitoring that is planned for a duration of two years. The concrete-technological monitoring is supported by TU Vienna and the concrete laboratory Smart Minerals GmbH which provide the specialist knowhow over the observation period of at least two winters. Since the acoustic barriers of recycled concrete are part of a acoustic barrier installation reinvestment comprising a total of 6,000 m², the performance of the environmentally responsible material composition can be directly compared to a conventional concrete bearing course. “A functioning circular economy must be the future. We are very pleased that we, as ÖBB, can make a further contribution to sustainable and resource-preserving use of recycled concrete,” says Tanja Hofer, Project Manager at ÖBB-Infrastruktur AG.

Ready for the next step

Co-Managing Director Franz Buschmüller explains: “In various research collaborations we have already made all preparations – among them with Smart Minerals as well as with the raw materials section of our Group – to use concrete with a recycling share of 30%. The challenge is here, to guarantee the quality requirements placed on the respective applications with the aggregate obtained from the old concrete.”

After the end of the test phase

“The industrial sector as a whole must first adapt to the framework conditions with all relevant technical standards and quality standards.” Whether recycled concrete can be used also in other sectors will become clear only after the end of the test phase. Therefore, some time will pass until recycled concrete will be used on a large scale. Kirchdorfer possesses already today the appropriate product quality, experience and delivery chain and is ready. As corporate group recycling of mineral construction materials is seen in a larger context with the objective to implement the aimed for sustainability strategy goal throughout the group.