Study On Control System Of Laser Measurement&Platform For Surface Texture Of Coarse Aggregate In Asphalt Mixture

The surface texture of coarse aggregate has a significant influence on the anti-sliding performance of asphalt pavement and cohesive force of aggregate and asphalt.The surface texture contains the main information such as roughness,surface wave and outline and so on.The size of micro texture roughness is the main influence factor that determine the pavement skid resistance and the bond strength between asphalt and coarse aggregate.In this paper,a new measuring device is designed and based on Gauss filtering technique,a set of method is given in order to extract surface roughness of coarse aggregate,surface waviness and outline.In this paper,both domestic and foreign laser measurement technology,used for measuring the surface texture of coarse aggregate is studied and a set of soft hardware measurement and analysis system,used for measuring,collecting and analyzing the surface texture of coarse aggregate is developed.A non-contact laser displacement sensor is used as a measuring device.In order to measure the full range of coarse aggregate and analyze the relationship between the surface texture of coarse aggregate and adhesive force of asphalt,the three-dimensional moving platform,used for longitudinal measurement,circumference measurement and global profile measurement is designed,which is consist of the lifting device,rotating device and translation device.The stepper motor and the programmable controller(PLC)are respectively used to drive and control the measuring platform.In order to avoid appearing out-of-step and oscillation of.stepping motor,a method of lifting and decreasing speed,based on parabola and straight line is presented.The method of Gauss filter was used to extract the roughness,surface wave and contour from the measured surface texture data of coarse aggregate.In this paper,based on Gauss filter technology,the method used to extract the surface texture information of coarse aggregate is proposed and a method used to measure one dimensional roughness value of coarse aggregate micro texture Ra is provided,which provide a basis for analyzing the respective relationship between micro and macro texture with.adhesiveness of asphalt.