Effect of Compound Flame Retardant on Pavement Performance of Asphalt Mixtures with an Aggregate of Granite

The influence of types and addition of flame retardants on properties of SBS modified asphalt was investigated.Effects of the homemade compound flame retardant on pavement performances of asphalt mixtures(AC-13C and SMA-13) with an aggregate of granite were studied.The test results show that compound flame retardant act as not only a good flame retardant,but also a good smoke inhibitor.When the dosage of flame retardant is 10%,the oxygen index of SBS modified asphalt increases to 25.8%.The dynamic stability of asphalt mixtures(AC-13C and SMA-13) with an aggregate of granite was slightly improved by compound flame retardant,while the retained stability ratio and freeze-thaw split strength ratio were reduced remarkably.It was noticeable that the freeze-thaw split strength ratio of the two types of flame-retarded asphalt mixtures decreased to 70.1% and 70.7,about 17.1% and 16.7% downcompared with asphalt mixtures where the flame retardants were not added.In the tunnel environment of high groundwater level and serious freeze injury,these two types of flame-retarded asphalt mixtures with an aggregate of granite are not recommended.