Preparation Of Composite Flame Retardant And Research On Performance Of Flame Retardant Asphalt Mixture

With the rapid development of my country’s transportation industry,the tunnel highway as an important part of mountain road construction has attracted wide attention in the industry,and the scale of tunnels in the central and western regions continues to break new heights.At present,the tunnel pavement in use in my country is mainly asphalt pavement.With the increasing scale of highway tunnels,the continuous increase of vehicle speed and traffic volume,coupled with the limited view of the tunnel,the tunnel accidents continue to occur,and it is very easy to cause spontaneous combustion of vehicles and cause tunnel fires.When a fire occurs in a tunnel,the temperature can quickly reach 800°C.Coupled with the special structural characteristics of the tunnel itself,it often causes dangerous conditions such as high heat and toxic smoke.The burning of the asphalt pavement also hinders rescuers from moving and seriously threatens people’s driving safety.Therefore,the experimental research on flame retardant asphalt pavement materials has important practical significance.First,based on the existing research,four flame retardant components of APP,ATH,MH,and HL are selected,and a four-factor,three-level orthogonal test is designed,and the three indicators and the four limiting oxygen index are considered to determine the best matching plan——APP: ATH: MH: HL is 30: 8: 15: 6.The technical performance of composite flame retardant asphalt was studied through DSR,Brinell rotational viscosity test,segregation test,and limiting oxygen index test.The results show that the addition of composite flame retardant can reduce the temperature sensitivity of asphalt,and is stable to flame retardant performance and high temperature.Performance and antirutting ability have a positive effect.Considering the construction temperature and storage stability,the compound flame retardant content should not exceed 12%.Secondly,the effect of composite flame retardant on the combustion behavior of SBS modified asphalt was analyzed through TG thermogravimetric test.The results showed that the thermal decomposition trend of SBS modified asphalt and composite flame-retardant modified asphalt are roughly the same,which can be roughly divided into three stages;The asphalt kinetic parameters change greatly after adding flame retardant.The non-isothermal kinetic model of each stage of asphalt combustion is different.There is a compensation effect between the activation energy E and ln A,and the asphalt combustion can be analyzed in combination with the level of the compensation line.Behavior: The blending of composite flame retardants increases the activation energy E in the first and second stages of asphalt combustion,and the flame retardant effect is better.Then,through rutting test,low temperature bending failure test,and water immersion Marshall test,the influence of the addition of composite flame retardants on the road performance of the three gradation types of mixtures is analyzed.The results show that the addition of composite flame retardants can improve the asphalt mixture The high temperature performance,low temperature performance,and water stability performance of the material.Among them,the high temperature performance has the most obvious improvement effect on the AC type asphalt mixture;the maximum flexural strain and the water stability improvement effect of the SMA type asphalt mixture are the most obvious.The road performance of graded type mixture mixed with flame retardant all meets the specification requirements.Finally,through direct combustion tests,an exponential relationship model for the mass loss rate,residual stability ratio and combustion time of the three gradation types of asphalt mixtures after combustion is constructed,as well as the polynomials of residual dynamic stability,residual maximum flexural strain and combustion time.The relationship model is used to study the flame retardant performance of asphalt asphalt mixtures.The results show that the burning time and mass loss rate of the three graded asphalt mixtures after adding composite flame retardants have decreased,and the residual dynamic stability and residual The decline rate of the maximum flexural strain is significantly slower,and the decline rate of the residual stability ratio is not changed much.The final residual road performance is higher than that of the SBS modified asphalt mixture,indicating that the addition of composite flame retardants can reduce the burning of the asphalt mixture.The speed of road performance decline has a positive impact on the flame retardant properties of the mixture.