Negative Texture, Positive for the Environment: Results of Horizontal Grinding of Asphalt Pavements

A pavement surface having its texture deflections mostly directed downwards is said to have a “negative texture” and is expected to result in positive tire/road noise and rolling resistance properties. Negative textures are typical of porous asphalt pavements, but another way to achieve this is to grind-off the top of the asperities of a rough-textured surface. This paper explores the application of grinding pavement texture by tools operating in the horizontal plane (not to be confused with common “diamond grinding” which is made by tools operating in the vertical plane) on a number of asphalt pavements in Sweden, including porous asphalt and stone matrix asphalt. Noise measurements with the Close Proximity method were carried out to evaluate the different acoustical performance of the ground and the original surfaces. In most cases, also tire/road rolling resistance was measured. Texture and wet friction measurements were carried out to characterize how the grinding operation changed the surface texture. It was demonstrated that the grinding treatment led to a more negatively skewed surface texture, resulting in an A-weighted noise reduction up to 3 dB, while rolling resistance coefficients were reduced by up to 15 %. It is concluded that horizontal grinding indeed creates more “negative textures”, which results in improved noise and rolling resistance properties without sacrificing friction, though with limited longevity.