Fibers to help fire damage prevention in tunnels

Engineers at the Technical University of Munich (TUM) have come up with a way to prevent concrete spalling caused by excessive temperature built up during a tunnel fire. The new technology consists of fibers added in the concrete but the changes in concrete behavior remain still to be investigated.

In case of a tunnel fire, induced heat, easily exceeding 1000 degrees Celsius, is difficult to escape, causing the water in the concrete to vaporize. As vapor pressure continues to built up, a process known as explosive spalling is initiated, reducing the concrete's thickness and the tunnel's structural integrity. Engineers from the Technical University of Munich found out that concrete spalling may be prevented by adding polypropylene fibers to the concrete, which start melting, creating small pockets into which the pressure of the vaporized water can be dissipated.

TUM scientists in collaboration with the Institute of Construction Materials of the University of Stuttgart and the MFPA Leipzig GmbH have developed a measuring method based on cracking sounds in the concrete. This new fiber-enhanced concrete technology is still in experimental stage, and scientists hope to compare the fire-resistant behavior of different mixtures in the coming months. 

To learn more about the project, please click here!