Development of a virtual mean texture depth estimation method for asphalt concrete using 3D surface scans

Advancements in laser scanning technologies have made it possible to scan and interpret the surface of a pavement within minutes. However, rectifying the traditional surface texture measurements, like the sand path test, with those calculated from laser scans remains a challenge. This paper addresses some of these challenges by developing a method that uses surface laser scans to virtually determine the MTD (i.e., VMTD). Asphalt samples, 68 field cores and 30 laboratory-prepared samples, were used to develop and validate the algorithm. A threshold percent change in VMTD (COVMTD) with respect to the scanned surface height is defined and used to establish the surface sample position for computing VMTD. It is found that a COVMTD limit of 95.5% and 97.8% is ideal for field cores laboratory-prepared samples, respectively. These different values are a result of variations in the surface skewness between the sample types. Thus, a model is developed based on the material ratio of the surface to more generally predict the ideal COVMTD limit for any surface. It is shown that the proposed COVMTD model and the VMTD algorithm can be coupled to produce accurate estimates of the MTD using a 3D surface scan.