Research For Preparation Of Flame-Retardant Asphalt And Mixture Performance

Asphalt concrete pavement was widely used in highway tunnel construction projects, andflammabilities of asphalt were consistently concerned by relevant experts in domestic andforeign. Therefore, in this study, numerous references and research achievements have beenabsorbed and integrated comprehensively. However, a new inorganic composite flameretardant has been made, in order to systematic researched the influence of flame retardantadded to various performance, which included asphalt properties, flame retardant mixture androad performance.First of all, four kinds of materials which were composed of magnesium hydroxide,melamine, ammonium polyphosphate and titanate, have been used to design a L9（34）orthogonal experiments. Thus nine different formulations retardant intermediate have beenmade, and titanate has been set to five different dosages based on3%to7%of formulationsretardant intermediate dosages. Through surface modification on intermediate to get MAM-Ti,then the optimal dosage of titanate was determined as6%in the50~200range, which wasbased on tests of oil absorption rate and activation index performance.Nine different formulations of MAM-Ti flame retardant was made according tothe material mixture ratio. Which were respectively added to asphalt based on theasphalt dosage of4%,6%,8%,10%, and through the high speed shearing about half an hour,36groups of flame retardant asphalt have been made in order to test the performance ofasphalt and limit oxygen index. Meanwhile, Oil absorption and activation index wereconsidered, and multi-index orthogonal test.Test#3was the best flame retardant formulation, which was selected in nine differentformulations. Flame retardant asphalt test results have shown that the optimum amountof flame retardant was5%.Mixture ratio was designed according to the molding method of hot mix asphalt, andfractal distribution of mineral aggregate was used to verify the mixture ratio. Flame retardantsdosages were initially identified based on asphalt dosages of0%,4%,6%,8%and10%. Plusthe addition and method of flame retardants to be used when marshall specimen was molded.Indicators were tested separately, such as bulk density, flow values, stability, porosity, voidsin mineral aggregate, saturation, etc. Test results and graphical analysis have shown that plusmethod was the best way to add flame retardants when flame retardant dosages were variedfrom0%to10%range. The road performance of ordinary asphalt mixture, retardants Aasphalt mixture and retardants MAM-Ti asphalt mixture were comparatively researched.The results have shown high temperature performance, low temperature performance,water-stable performance specifications of three kinds mixture were able to meet theregulatory requirements, but the water stability of MAM-T was slightly lower than regulatory requirements. Thus the combustion performance were studied respectively, which includedburning time, mass loss, surface temperature, residual stability and dynamic stability changes.The test results have shown that flame retardant properties of flame retardant asphaltmixture were better than common asphalt mixture’s. It also found that flame retardantproperties of MAM-Ti flame retardant asphalt mixture were better than A’s asphalt mixture.Finally, based on the characteristics of flame retardants research and market surveys, itwas MAM-Ti flame retardant that have both realistic significance and economic value, thus itcould be used in tunnel concrete pavement.