Implementation of Close Range Photogrammetry to Evaluate Distresses at Asphalt Pavement Surface

Abstract

Roadway pavements surface deteriorate with time because of traffic loading, environment conditions, and poor pavement maintenance management. The aim of this research is to implement close range photogrammetry technique for evaluation of the pavement surface distresses. The assessment was based on comparison with the traditional visual inspection method and validation of its equivalency with visual evaluation. The asphalt concrete pavement surface distresses such as (cracking type and crack width, patching area, rut depth and potholes area and depth) have been assessed. The visual inspection was conducted by walking through the roadway and evaluating the pavement surface distress visually. As for the photogrammetric fieldwork, it starts with generation of ground control points around the area of distress. A total station device (Topcon, GTS 235) was used to measure the coordinates (X, Y, and Z) for GCPs and the initial camera positions. The coordinates of two points (two base stations) referenced these coordinates. Within the study area, forty vertical stereo pair images of different pavement distresses were captured using a non-metric DSLR camera. Photogrammetric process was carried out by using ERDAS IMAGINE software Version 8.4 to create ortho-images and evaluate pavement surface distress. Window measurement tool in ortho-rectified image provides all the fundamental quantitative measurement functions necessary to measure length, area, width and other pavement distress condition. Results of the two techniques (photogrammetric and visual methods) were modeled. It was concluded that using photogrammetric approach is efficient in evaluating the pavement with a high (R2) range between (0.985 and 0.999) as compared to the visual evaluation. Further, the photogrammetric technique could provide a permanent documentation of the pavement surface condition, which could be referred when needed.