Comparison of Fire Resistant Geopolymers for Passive Fire Protection of Concrete Tunnel Linings

Abstract

Fire resistant geopolymers are developed and the performance under thermal loading is examined and compared in this paper. The geopolymers were prepared by mixing the solid phase, metallurgical slag and metakaolin with a highly alkaline potassium hydroxide aqueous phase in order to create a paste that was subsequently cured at 70˚C for a certain period of time. The developed materials were tested for the mechanical, physical and thermal properties. The behaviour of the geopolymers upon exposure on fire was studied following the EFNARC guidelines for testing of passive fire protection for concrete tunnels linings. The geopolymers were subjected to the most severe fire scenario, the Rijks Water Staat (RWS) temperature-time curve. Both geopolymers appeared great behaviour after the test reaching temperature lower than the RWS test requirement, proving the ability of both materials to work successfully as an efficient thermal barrier. Thus, the concrete slab protected by the...