Study On Preparation And Properties Of Reactive Cold Mix Recycled Asphalt Mixture

Hot mix and warm mix recycled asphalt mixture need to be heated in the process of production and construction process,environmental pollution and energy consumption exist in varying degrees.Traditional cold mix recycled asphalt mixtures also have some problems,such as low initial strength and slow strength increase.In this paper,reactive liquid asphalt,combined with inorganic active powder curing agent,recycled asphalt pavement(RAP)and mineral materials,were used to produce reactive cold mix recycled asphalt mixture,avoiding the problem of heating in the production of HMA and WMA technology,and improving the road performance of the resulting modified asphalt and mixture through reactive diluent-curing agent system.The main research contents include:(1)Using penetration,softening point,ductility,Brookfield viscosity as evaluation indicators,single factor experiment and orthogonal experiment were conducted to determine the best formula of reactive liquid asphalt and curing agent.The result was SEBS:naphthenic oil:reactive diluent:inorganic active powder curing agent=4%:8%:35%:9%.(2)Various performance tests were carried out on the optimal formulation of reactive liquid asphalt:Brookfield viscosity at 60℃ was 2.57 Pa·s,adhesion grade was 4 or higher,ductility at 15℃ was 37cm,and softening point was 76℃,penetration(0.1mm)was 48,PG grade was PG70-34.It showed that after SEBS modification,the high-temperature performance and low-temperature performance of the asphalt had improved.and the curing reaction was beneficial to improve the performance of asphalt.(3)According to the results of RAP screening test,the synthetic gradation of the recycled mixture was selected as AC-13C on the basis of its particle size change rule.The RAP surface was pretreated,and the RAP blending range was selected to be 30%-60%.Then the optimum asphalt dosage for different RAP blended recycled asphalt mixtures was obtained by Marshall test results.(4)The road performance test of the reactive cold-mixed recycled asphalt mixture was conducted,and the results showed that when the RAP content was gradually increased,the construction workability and anti-skid performance of the recycled mixture were basically unchanged,and its Marshall stability,water stability and low temperature crack resistance were weakened whereas the high temperature stability was enhanced.When the amount of RAP was 40%,the mixture had good road performance,in which the initial stability and molding stability were 4.63kN and 9.43kN,the residual stability of immersion in water was 82.7%,the freeze-thaw splitting tensile strength ratio was 76.1%,the dynamic stability was 3471 times/mm,the failure strain at low temperature bending test failure strain(με)was 2406.9,and the structural depth was 1.2mm.