Chemistry of Innovations 

In the construction process of the Swiss Gotthard Base Tunnel, which will be one of the longest train tunnels in the world, concrete has to fulfill conflicting requirements: On the one hand wet concrete must not harden while being transported through the mountain for several kilometers, on the other it has to harden in an instant, when being sprayed onto the tunnel wall. Additives to concrete uses such as accelerators and plasticizers make it possible. In addition, a sprayable fire protection mortar prevents concrete from exploding when being exposed to temperatures above 500 degrees Celsius.