Befestigungstechnologien in Beton mit Gesteinskörnung aus Tunnelausbruchmaterial

Fastening technology in concrete with aggregate from tunnel excavation material

Concrete production for the use in constructional engineering is implemented and harmonized throughout Europe by European standard EN 206. However, does structural concrete not comply with the requirements covered by this standard, experimental validation of properties of hardened concrete by relevant experts is permissible. The approval procedure of post-installed anchors in concrete, in turn, is regulated in the European Technical Approval Guideline ETAG 001. In this guideline, standard concrete with a compressive strength class of C20/25 resp. C50/60 is used as basis for anchor approval procedures. Further applications in different concrete products are not covered by the European Technical Approval Guideline. At large tunnel construction projects large quantities of excavation material are generated, nowadays commonly processed and recycled as aggregate for concrete and typically used in the construction of the tunnel itself. An open-ended question within the topic of material recycling is the suitability of concrete made of recycled aggregate in accordance to the guideline on Inner Shell Concrete for post-installed fastening systems. For this reason, investigations using various post-installed anchor systems in Inner Shell Concrete made of recycled aggregate (Bündner schist from the Brenner Base Tunnel) have been carried out. Due to application-related considerations, evaluation of the post-installed fastening systems was performed in unreinforced as well as in steel and PP fiber concrete. On the basis of material characterization displacement and load bearing behavior as well as specific failure type characteristics of the various fastening systems in different Inner Shell Concretes were compared to obtain an assessment of the applicability of these systems in concrete with aggregate made of tunnel excavation material.