Study On The Performance Of Recycled-modified Asphalt And Its Mixture

With the rapid development of highway construction in our country,some highways that constructed earlier should be maintained in succession.It will be produce a lot of reclaimed asphalt pavement(RAP).If RAP is not handled well,it will not only waste non-renewable petroleum resources,but also damage the ecological environment.Asphalt pavement recycling technology can be used to regenerate RAP,then it can be reapplied to road construction and maintenance project to achieve the purpose of RAP recycling and environmental protection.However,considering that the early road surface was paved with matrix asphalt,so the pavement performance of asphalt mixture treated by conventional regeneration method is difficult to meet the requirements with the increase of traffic volume.Therefore,researchers adopt the approach that add modifier to recycled asphalt to regenerate the aged asphalt.The matrix asphalt pavement will be became modified asphalt pavement by regeneration and modification,and the pavement strength level is improved and the road life is extended.Therefore,the performance of recycled-modified asphalt and its mixture were studied experimentally to provide a experimental and theoretical basis for asphalt pavement recycling and modification technology.To this end,the following research efforts were made in this dissertation:(1)Study on the aging and regeneration mechanism of asphalt and the content of rejuvenating agent.Firstly,the aging mechanism and regeneration mechanism of asphalt were analyzed,and then the conventional method and SHRP method were used to determine the reasonable amount of rejuvenating agent.(2)Study on the performance of recycled-modified asphalt.The three indexes of bitumen,Brookfield viscosity(RV),temperature sweep,frequency sweeping,multiple stress creep recover(MSCR),linear amplitude sweep(LAS)and bending beam rheology(BBR)tests were performed on the recycled asphalt samples.In order to analyze the viscosity,high and low temperature performance and fatigue properties of recycled asphalt.The results indicated that the performances of recycled-modified asphalt were significantly better than that of 90# original asphalt and ordinary recycled asphalt.In addition,its performances were gradually improved with the increase of modifier content.Based on the evaluation of macro-performance,in terms of microstructures and properties of recycled-modified asphalt,the study utilized fluorescence microscopy(FM),Fourier transform infrared spectroscopy(FTIR)to discuss the phase distribution,ageing mechanism,recycling and modifying mechanism of asphalt.(3)According to the evaluation and analysis of asphalt properties,the paper also evaluated the pavement performance of recycled-modified asphalt mixture.The mechanical performance,high temperature performance and water stability of recycled asphalt mixture and recycledmodified asphalt mixture were evaluated.The results indicated that the performance of the recycled-modified asphalt mixture has been improved and even reached the level of the modified asphalt mixture.It showed that the scheme of regenerating and modifying on the matrix asphalt pavement was feasible and practical.