Suppressive effects of composite flame retardant on smoke release, combustion soot and residue constituents of asphalt mixture

Abstract

Asphalt pavement has been widely applied in the road tunnel. In tunnel fire, the combustion of asphalt pavement produces large quantities of toxic, carcinogenic and harmful black smoke, which causes serious environmental pollution. To explore the inhibition of composite fire retardant (CFR) on combustion soot release of asphalt mixtures for reducing environmental pollution, this paper investigated the combustion soot produced by asphalt mixtures using cone calorimeter (CONE) test. Then the influence of CFR on the composition of combustion residues in asphalt mixture was investigated employing the solid-phase microextraction combined with gas chromatography-mass spectrometry (SPME-GC-MS) technique to reveal the smoke suppression mechanism of each constituent of CFR on the combustion of asphalt mixture. Through the detection and analysis of the combustion soot of asphalt mixture and CFR asphalt mixture, it is found that the main types of alkanes are reduced, and the unsaturated alkenes and alkynes disappear after the addition of CFR. Test results show that the composition of combustion residues of CFR asphalt mixture is significantly reduced compared with that of asphalt mixture. Compared with the combustion soot and residues of CFR asphalt mixture, it is found that the molecular weights of characteristic substances of combustion soot and residues after the burning of asphalt mixture are smaller. Therefore, it is of great significance in the fire safety field to study the influence of newly developed CFR on the combustion soot and combustion residues of asphalt mixture when exposed to fire.