Application Research On BRA Modified Asphalt Overlay Technology For Resonant Rubblization Of Existing Cement Concrete Pavement At Urban Road Intersection

In order to solve the problem of rut disease of asphalt pavement at urban road intersection caused by large traffic volume and horizontal load as well as complex traffic conditions etc.,relying on the improvement and reconstruction project of Changsha Panpan Road,and combined with the resonance rubblization recycling of existing cement concrete pavement and BRA modified asphalt overlay technology,the green durability anti-rutting technology of asphalt pavement at urban road intersection is researched,so as to comprehensively improve the anti-rutting ability and durability of asphalt pavement at intersection.1)By analyzing the test data and evaluation results of disease conditions of asphalt pavement at 12 typical flat intersections in Changsha City,and combined with the actual situation of the supported project,the overlay range of the durability asphalt pavement structure at flat intersection is defined as:100m before entering the flat intersection parking line to 50m after leaving the flat intersection parking line.Then the pavement structure design scheme is proposed as:resonance rubblization layer+BRA modified asphalt overlay.2)The mix design and pavement performance test of BRA modified asphalt overlay mixtures in the middle and lower surface layers of the supported project were carried out under six different BRA mixing amounts at the range of 0%～5%.The results show that the incorporation of BRA can improve the high temperature stability and water stability of asphalt mixture,but it will reduce the low temperature crack resistance to a certain extent,which is suitable for use in high temperature and rainy areas in southern China.Combined with the engineering practice,the optimal mixing amount of BRA is determined as 3%for the modified asphalt mixtures in the middle and lower surface layers.3)The natural frequency and the safety influence distance of resonance rubblization construction were tested for the existing cement concrete pavement in the supported project.The resonance region range of the existing pavement slab is obtained as 35.5～50.3Hz,and the horizontal and vertical safety influence distances of construction are 5m and 1m,respectively.Combined with the field construction situation and engineering experience at home and abroad,the mix design and pavement performance test of SBS modified SMA-13 in the upper surface layer were carried out,and its results meet the specification requirements.Then,the production mix design of each asphalt overlay mixtures was carried out,and the construction technology and key quality control technology were clarified for resonance rubblization layer,BRA modified asphalt overlay and SBS modified SMA-13 upper surface layer.4)The test results at construction site and after completion show that the construction quality control of resonance rubblization layer and BRA modified asphalt overlay is strict,and the pavement performance is excellent.At the same time,the technical and economic analysis of the overlay scheme was carried out,and the technology is reasonable with good economic,social and environmental benefits.In summary,the research results of this thesis can provide a reliable basis for durability anti-rutting technology of asphalt pavement at urban road intersection,which has important practical significance and engineering application value.