Development of bottom ash and PP fiber added fire protection coating mortar for NATM tunnel concrete lining

Underground spaces, like tunnels, have confined conditions. So tunnel fires can result in severe human casualties and structural damages. In recent years, in order to prevent these problems, clients are requesting that tunnel linings should be fire-resistant. Fire protection coating on the surface of concrete can give sufficient fire-resistant capacity to tunnel linings, reducing the risk of lining and ground collapse during or after a fire. Also the cost is very sensitive issue in popularizing the material. The newly developed cementitious fire protection coating material contains bottom ash and PP (polypropylene) fibers, which play important role in fire-resisting ability. The newly developed cementitious fire protection coating material has much better strength than the other fire protection materials currently available in the market. This paper describes the results of fire tests of the newly developed cementitious fire protection coating material applied concrete tunnel lining specimens for the application in tunnels.