Tunnel Concretes Under Fire:
Part 1- Explosive Spalling

Tunnels in general use a large amount of concrete.This article concerns its self with the higher humidity in tunnels, around the 75% mark compared to regular buildings which experience an average of 50%. This increase the risk of explosive spalling in tunnels during fires. Concrete spalling in fire can be classified as different forms, aggregate, surface, explosive, corner, sloughing-off and post cooling spalling. This article presents the concepts behind a test program on large-scale specimens aimed at separating out for the first the underlying mechanics of explosive spalling.


The above information is taken from "Concrete for the Construction Industry, Vol 40,Num 10, November 2006 "page 62-63