Results of the research project “Recycling of tunnel excavation material”

It is shown that the gap between calling the mineral resources as waste on the one hand and as a product on the other hand is not caused by technical specifications but by legal regulations. The main objective of the ÖBV research project is to reuse respectively to utilize the excavation material. According to the "Waste Framework Directive 2008/98EC" published in 2010 waste prevention has gained weight; however, the legal conditions are still not satisfying and a technical set of rules is required. Based on the utilization of the excavated material for concrete production on-site, necessary transports for depositing the excavation material and bringing aggregates to the tunnel site can be reduced, which at the same time causes a reduction of CO2-production, mineral resources reserves are conserved and the required landfill spaces decrease. As the perhaps largest part of the excavated material is used for concrete production – not only for the tunnel project itself – concrete technology studies were performed by using lithologies which are representing a cross cut of excavation materials which are expected in Austrian underground infrastructure projects of the future. In order to standardize the procedure to use tunnel excavation material in the industry it is in-tended to publish a guideline by the Austrian Society for Construction Technology in the near future.