Gotthard base tunnel: Testing system for concrete mixtures

AlpTransit Gotthard is a future-orientated project for a high speed railway through the Swiss Alps. The base tunnel under the St. Gotthard massif - with 57 kilometre the world's longest tunnel - is the core structure of the new transalpine Gotthard railway-line. This 21st century project will significantly improve passenger travel and freight transport in the heart of Europe. The main features of the project and the processing of the excavated material will be presented. The applied testing system for concrete mixtures, the contractual conditions and the implementation on site will be explained. The construction of the Gotthard Base Tunnel will produce approx. 24 million tonnes of excavated rock. This huge amount of material has a large potential to be converted into concrete aggregates. Already in 1993 an innovative testing programme for concrete mixtures was launched in order to prove that high-quality concrete can be produced using TBM-excavated material. The permanent testing on site ensures, that the produced concrete will meet the high requirements in tunnel construction.