Thermal Barriers and Fibre Concrete Roles in the Passive Fire Protection of Tunnels

Following a number of notable traffic tunnel fires in Europe that have led to loss in human life, severe structural damage and extended periods of loss in service due to repair, the methods of structural fire protection and tunnel user safety have been investigated by numerous agencies in Europe in recent years. Both passive and active fire protection systems are seen as necessary elements of a tunnel fire safety system in a holistic approach to effectively combat the devastating effects of fires. In light of ongoing studies and research a great number of systems are entering the industry. It is apparent that worldwide there is a lack of understanding of the role of these systems employed in tunnels, which this paper attempts to rectify. With respect to fire protection of structural concrete tunnel linings, the paper establishes the roles of passive and active systems, then examines the protection performance of fibre modified concrete and spray applied thermal barriers. Based on the performance of each system, and taking into consideration various risk factors, the paper suggests appropriate passive systems for existing and new build tunnel structures. The views expressed in this document are those based on currently known issues and requirements in the tunnel fire protection industry and are the views of Degussa Construction Chemicals. The authors are aware that further research studies are being conducted in both fibre-modified concrete and thermal barriers.