Application of three-dimensional printing to pavement texture effects on rubber friction

Despite the significant attention gained by the three-dimensional (3D) printing technology in many research fields, it has not yet found application in tyre-road friction and pavement engineering. To better understand the impact of different roughness length scales on rubber friction, the feasibility of utilising 3D printing for replicating pavement texture and the strength of this technology in creating customised roughness patterns are investigated. An image-stitching algorithm was developed for a common portable optical profiler in order to obtain a large topography of an asphalt specimen for friction experiments. The printed topography showed a replication efficacy down to 0.5mm in wavelength. Printed samples with artificial surface patterns were then generated by random process theory and fractal modelling. Rubber sliding tests implied different frictional behaviour between the asphalt specimen and its printed replica, which was mainly attributed to severe wear of rubber on rougher asphalt specimen. For artificial geometries, friction increased as the Hurst exponent (H) increased. Results also suggested that reducing roll-off wavevector (q(0)), that is, increasing maximum aggregate size, reduces friction coefficient of a fractal surface.