Assessment of average macrotexture depth using a direct volumetric technique such as the sand patch test is a time-consuming process and able to evaluate only a small sampling of the pavement surface. While the importance of measuring macrotexture depth is well established, high volume textureevaluation must currently be provided through laser-based devices, whose initial cost remains prohibitively high for many agencies and end users.As part of a greater texture and friction investigation, a low cost and high volume macrotexture evaluation technique has been developed using digital image analysis. Specifically, novel application of lacunarity analysisand scene lighting is able to determine the average particle size of an imaged pavement surface. The average particle size was highly correlated with Mean Texture Depth (MTD) as determined by the sand patch test. The digital sand patch test however is able to collect data at a rate of 7 to 10 times faster, without the need for specialized materials, and is not affected by wind. The analysis technique also appears sensitive to asphalt segregation, although additional investigation is required.
Samenvatting