Study On The Segregation Mechanism Of Asphalt Mixture And Evaluation Index

Segregation of asphalt mixture results from gradation, temperature and construction factor during construction. But we cannot promptly detects and differentiates segregation grade of asphalt mixture. Meanwhile, selects corresponding treatment methods with it. So that there is pavement segregation in the end, it's working life is sharply shortened. This paper analyses relations segregation of asphalt mixture with pavement segregation with the help of testing on the spot and interior experiment. Sums up definition for segregation of asphalt mixture on the basis of construction condition of asphalt mixture, and generalizes temperature difference and gradation ratio property of asphalt mixture. According to construction condition of asphalt mixture, divides segregation of asphalt mixture into aggregation segregation, temperature segregation and paving segregation.Analyses contact force and contact moment of asphalt mixture under own weight during each particle moving with soft ball model about particle mechanics. Research result shows that different type can different contact force and contact moment, it may causes liable segregation for smaller contact force and stronger contact moment. Meanwhile, analyses the basic segregation reason under external force with motion and kinematical analysis methods. Research result shows that it may causes liable segregation when distance between particle and spreader is from 0.1 to 0.6 spread of axles, results in circular velocity is much faster axial velocity, makes asphalt mixture moving along aggregate velocity.Firstly, puts forward segregation model with the help of Angle of repose. Describes separ- ation degree in view of moving distance of asphalt mixture and points out segregation index, and develops instruments for testing segregation and deduces calculate equation for segregati- ation index of potential energy. in the light of the soft ball impacted mechanics. Segregation index of potential energy relation to the texture deep and pavement segregation were establi- shed in the C project on the spot by visual identification and the sand patch method. Indicates the standard of segregation index of potential energy about maximum nominal particle size 16 mm, and divides segregation grade of asphalt mixture into no segregation, low segregation, middle segregation and high segregation .Movement behaviors of asphalt mixture is explained and analysed with the linear contact model on the basis of particle mechanics basic theory of motion law and force-displacement law. All of particles complies with Gaussian distribution, meanwhile calculates particle numbers According to mass percentage, and selects parameter of particle and wall. The gradation of Bailey method about the maximum nominal particle diameter 16 mm is simulated by PFC2D, such as CA0.2, CA0.4, CA0.5, CA0.6, CA0.8. Determine moveability of asphalt mixture through rolling distance of accumulation particle it's when asphalt mixture is stable at the gravitation. Computer simulation result is identical to testing result. On the basis of Bailey design method, reaches reducing segregation of asphalt mixture,and controls it treatment methods in view of the paver structure characteristic during construction.