Research On The Performance Of The Flame Retardant Asphalt Pavement And Asphalt Mixture In Tunnel

Recent years,with the rapid development of highway construction,the long tunnels grow more and more.Compared to the cement concrete pavement,asphalt pavement has become the mainstream of the tunnel road pavement because of its smoothness,no connection joints,driving comfort,small vibration,lower noise and other advantages.But asphalt is a flammable material,once the temperature rises to a certain extent,the fuel combustion will produce large amounts of toxic gases and smoke and result in tunnel fires.Therefore,it is important to study the fire-retardant technology of asphalt road in tunnel.To achieve flame-retardant,most of the flame retardant trapped free radicals and suppressed oxidation in order to achieve the effect of flame retardant mainly by adding flame retardants.However,inhibition of oxidation will not only lead to incomplete combustion of asphalt,but also increase the amount of combustion of raw tobacco.This paper focuses on achieving the new feature about smoke suppression as the premise-flame-retardant effect,selecting effective methods to evaluate the technical performance about fire-retardant asphalt and mixture.First,proposed the requirements to selection flame retardant.Selected several approach consistent with the requirements of low-carbon,economic and environmental friendly flame retardant solutions,using silane coupling agent(1%of the amount of flame retardant)to modified the surface of flame retardants.In this paper,the author made use of the limiting oxygen index and smoke density method to evaluate the flame combustion of asphalt,apply synergistic efficiency SE and flame-retardant value FRV to evaluate were synergistic flame retardant of different flame retardants and flame retardant economy.Secondly,researched on single flame retardants,binary and ternary compound flame retardant system impacting on asphalt oxygen index LOI and smoke density and analysis flame retardant SE and FRV Determine the optimal ratio of flame-retardant solution as follows:IFR is(APP:PER:MA):MH:(2%:0%:5%):20%;the optimum dosage of FRMAXTM is 8%;APFRR is 8%too.Determinate the three indicators of the asphalt after adding flame retardant,test results show that the asphalt penetration and ductility decreased,higher softening point.Then,based on the traditional SMA mixture design,the author used replacement method to prepare the flame retardant asphalt.Tests show that compare with the conventional SMA asphalt mixture,in the context of meet the specifications,the high stability of flame-retardant asphalt mixture has increased,low-temperature decreased,crack resistance,water stability and seepage coefficient changed little.Again,by direct experimental baking test and combustion simulation,discussed the amount of raw tobacco smoke temperature and raw when heated flame-retardant asphalt mixture in high temperature,and the burning time,burning surface temperature,mass loss of flame-retardant asphalt mixture and smoke density indicator,analysis of the combustion flame retardant properties of asphalt mixture.By using the changes of combustion Marshall Specimen stability and dynamic stability of the track plate specimen,the author evaluated the flame combustion of asphalt pavement performance.Finally,simulate that once taken place of fire in tunnel asphalt pavement by using FLUENT software,the author has discussed smoke density contours and the mass fraction on the different sections about general asphalt pavement and flame retardant in order to evaluate the smoke suppression performance.