ABSTRACT
Concrete lining structures are prone to spall induced by high temperature, which can be extremely dangerous for semi-closed tunnels, considering the relatively high humidity. This paper presents a novel active fire protection (AFP) system achieving by cement-based system consisted of ammonium polyphosphate-pentaerythritol-melamine (APP-PER-EN) composite with both fiber phase and particle phase. One-side heating experiments under open flame indicated that the thermally-triggered system functioned though melting, connecting and overflowing, which demonstrated a great retardant effect. Thermo-gravimetric analysis (TGA) and differential scanning calorimeter (DSC) were conducted to characterize the thermal behavior of the APP-PER-EN composite. Therefore, we believe that the novel system will exhibit a promising prospect for prolonging the life of lining structures after experiencing high-temperature environment.
