Research On Composition Design And Performance Of High Durable Pavement Asphalt Mixtures

As the asphalt pavement has many advantages such as high flatness, good drivingcomfort, low noise, good wear resistance and so on, it has been widely used inhigh-grade highway and urban road. Asphalt is a kind of heat-absorbing material withlow temperature stability, it is liable to soften and occure palastic flow deformationunder vehicle loads in summer, which will lead to high temperature disease such asrutting, cutting slippage, folding and so on, reducing riding comfort and security. It ismore likely to appear in special road section as road intersection and long steep slopebecause of vehicle braking or low speed driving. According to the serious hightemperature disease in asphalt pavement of special section, this paper raises a kind ofhigh durable pavement（HDP）additive brought from Japan, which can improve hightemperature performance of asphalt mixtures by modifying the thermoplastic mixtureinto thermosetting mixture. The compositions of HDP additive are main agent andsclerosing agent, adding them into asphalt mixture after well-mixed during mixingphase, then preparing HDP asphalt mixture, of which this paper researches on thecomposition design method and performance.Firstly, according to the existing technical requirements of epoxy asphaltmixturesthe in the domestic and overseas, the technical requirements of HDP asphaltmixtures are raised，the optimal asphalt content is4.8%and the additive content is20%.Compared with the optimal asphalt content of common asphalt mixture and itsdetermination method, HDP can increase Marshall stability, meanwhile the volumeindex as bulk density and air voids almost remain unchanged, from which acomposition design method is raised for HDP asphalt mixture.Secondly, the effect of mixing and holding temperature, holding time, compactionmolding temperature, curing temperature and time on indexes of HDP asphalt mixturespecimen such as air viods, Marshall stability and so on is studied to determine themaximum modeling operation time under different mixing and holding temperatures,the lowest compaction molding temperature and the optimum curing condition, whichshows that HDP asphalt mixture has long modeling operation time. It is suggested thatHDP asphalt mixture should mixing and holding at the temperature of175℃, themaximum modeling operation time is90min, compaction molding temperature isabove140℃, specimens should be cured for4d at the temperature of60℃. Then, some experimental studies are made to evaluate the performance of HDPasphalt mixture including high temperature stability, low temperature crack resistance,water stability, oil corrosion resistance, skip resistance and fatigue resistance, whichshows that HDP asphalt mixture is of excellent high temperature stability, waterstability and oil corrosion resistance, its low temperature crack resistance, skipresistance and fatigue resistance basically meet the operating requirement of specialsection in high temperature area at the same time.Finally, the composition of main agent and sclerosing agent as well as its reaction isanalysed by infrared spectrum to infer the process of curing reaction. According to theDSC curve under different heating rate, a epoxy curing model about HDP is builtbased on epoxy curing kinetics principle, which is used to determine HDP curingreaction type.