Analysis of the Pavement Surface Texture by 3D Scanner

Abstract

Interaction between vehicle and the pavement surface has the primary effect to the road safety. This phenomenon including adhesive and hysteresis forces influences the contact stresses which are responsible for appropriate interaction between tyre and pavement. Skid resistance of the pavement surface is evaluated by measurements of texture characteristics (depth of texture, morphology) and physical (sliding friction). World Road Association indicates that the friction coefficient decreased on the road below 0.45 will increase the risk of accident 20 times; when it goes below 0.30 the risk is 300 times higher.The macro-texture measuring is realised at present by non-contact profilometers evaluated texture of surface as a mean profile depth – MPD; and by volumetric method evaluated texture by mean texture depth – MTD. The micro-texture measuring can be realised by direct methods by using of microscope or another equipment with high resolution. However, these methods are used very rarely, indirect methods by pendulum tester is used more frequently. University of Žilina (UNIZA) uses for skid resistance measuring the own equipment TWO that measures the coefficient of longitudinal friction with 17.8% slide.Slovak Road Administration operated 23 long-time observed road sections for analysis of the pavement serviceability parameters. Friction coefficient is measured by Skiddometer BV11, texture with using one separately laser installed on measurement beam of Profilograph GE. Measuring of texture is along with analysis of surface unevenness. Evaluation of measured data suggests problems with reliability and repeatability of measurements, measuring of texture depth above all.Concerning these problems new possibilities of texture analysis are tested in UNIZA. Friction coefficient is measured by Traction Watcher One equipment. 3D scanners are tested for texture evaluation, mainly the ZScanner®800. ZScanner is high resolution equipment and measuring of surface texture enables evaluation of the amplitude and wave length of the surface irregularities. All the measured data are processed by algorithm created in MATLAB and compared with results obtained by standardized measuring methods. 3D scanner has a very important characteristic compared with 2D scanners that provides the analysis and following evaluation of more parameters (not MPD only). On the other hand the time-consuming of measuring process is a big disadvantage. Request for big data processing is a second problem of 3D scanners, but actual level of hardware and software possibilities can eliminates it.