Title: Applications of Micro-Synthetic Fibers for Resistance to Explosive Spalling in Fires

Author(s): T. Atkinson and P. C. Tatnall

Publication: Symposium Paper

Volume: 268

Issue:

Appears on pages(s): 79-88

Keywords: explosive spalling; fiber; fire; polypropylene fiber; shotcrete.

DOI: 10.14359/51663710

Date: 3/1/2010

Abstract:
This paper discusses the recent tragedies of a number of tunnel fires occurring in transport tunnels, and the effects of these fires on concrete tunnel support linings. The mechanisms of explosive spalling of concrete in fires is described, and the research conducted to assess the ability of fine, polypropylene fibers to mitigate the effects of explosive spalling in severe fires is described. The test program to assess the fire resistance of the 25 miles (40 km) of concrete-lined tunnels in the Channel Tunnel Rail Link project in the United Kingdom is described in detail. A program to ascertain the effects of using these fibers in shotcrete tunnel linings is also considered. These programs demonstrate that small quantities – as little as 1.7 lb/yd3 (1 kg/m3) – of mono-filament polypropylene fibers provide resistance to explosive spalling in fires. Examples of the application of this new technology are listed.