Performance Of Recycled Mixtures By Means Of Emulsifying Aged Asphalt Of RAP In Room Temperature

The construction of roads in china witnesses a great development in recent years. Since2013, the total highway mileage has reached104468kilometers, and asphalt pavements arewidely used in road structure. The maintenance period of large number of roads constructedafter1990comes, if the working life of asphalt is counted as15to20years. RAP comingfrom old asphalt pavement milling was increasing every year, it would do a lot of damage toenvironment if those waste materials were thrown away.Existing cold recycling technology used RAP only as aggregate because of the highamount of energy consuming. The difficulties in reducing old asphalt cause waste of it. Amethod of emulsified old bituminous mixtures in normal temperature is proposed to increaseusage of old asphalt in RAP and to improve pavement performance.The mechanism of normal temperature recycling, kind and amount of modifier used inrecycle are studied by lab tests. Then duration of mixing, moulding method and curing way ofspecimen are studied by test and experience. Basic properties for4types of proportion aretested, including air voids, splitting strength, immerse splitting strength and stress ratio offreeze-thaw splitting strength. The test shows that4types of recycled mixture can reachspecification requirements including air voids less than14%, splitting strength lager than0.5MPa, TSR lager than70.In addition, the recycled, aged mixture will be recycled again. The splitting strength andfatigue performance within ageing bituminous mixture of first and second time recycling arecompared through immerse split test, splitting fatigue test, and APA test. The results showsthat immersion splitting strength of4types recycled mixture after recycling are less than thatof first recycling, but still lager than0.5MPa, proving that this kind of recycled mixture innormal temperature can be recycled again. Fatigue performance of recycled mixture afterrecycling is slight less than that of first time recycled mixture. Type2and type3sees lessdecrease in fatigue performance, revealing that modifier and emulsifier working togethercontribute most to resistance of fatigue second ageing.