Concrete Pavement Contribution to Fire Safety in Road Tunnels

In recent years, several high-profile road tunnel fires have taken place across Europe. These fires inevitably led to important structural damages and even loss of lives. In all of these tunnels, national mandatory safety regulations were implemented. Nevertheless, disasters could not be averted. Apart from a deep knowledge of safety and fire equipment within a tunnel that is subjected to a fire, it is also essential for firefighters to have a profound knowledge of the fire dynamics inside tunnels and the influence of all the elements that contribute to the fire. One of the factors that modifies the behavior of fires inside tunnels is the type of road pavement. A recent study of the Spanish Technical Association of Firefighters shows that concrete pavements are inert elements and their interaction with fire is limited to the absorption of part of the heat generated. On the other hand, asphalt pavements are active elements that burn, releasing fumes and heat. This material can modify the spread behavior of the fire, worsening evacuation conditions and complicating the work of firemen. In some extreme cases, the use of concrete pavements may be the key factor that permits keeping the amount of heat and gases under the design limits, so that the extraction system continues working until the situation is under control. Evacuation procedures and the action of emergency teams will never be affected in this case. On the contrary, asphalt surfaces could complicate the situation. Safety contribution of concrete pavements during fires in road tunnels is widely justified by professional fire brigades and, therefore, they strongly recommend the use of concrete pavements in any road tunnel independently from their length. The paper explains the special characteristics of fires inside tunnels and the advantages of concrete pavements in comparison with asphalt pavements in this kind of situations.