|Major Topics on this Page|
Surface distress is "Any indication of poor or unfavorable pavement performance or signs of impending failure; any unsatisfactory performance of a pavement short of failure" (Highway Research Board, 1970). Surface distress modes can be broadly classified into the following three groups:
Thus, surface distress will be somewhat related to roughness (the more cracks, distortion and disintegration - the rougher the pavement will be) as well as structural integrity (surface distress can be a sign of impending or current structural problems).
|Pavement Distress Photo Gallery|
An extensive pavement distress photo gallery can be found in:
These galleries include all the major types of pavement damage/distress. Each distress discussion includes (1) pictures if available, (2) a description of the distress, (3) why the distress is a problem and (4) typical causes of the distress. The gallery is organized alphabetically and the pictures are not included in the Module list of figures.
Measures of distress can be either subjective or objective. A simple example of a subjective measurement may be a rating of high, medium, or low based on a brief visual inspection. Objective measurements, which are generally more expensive to obtain, use different types of automated distress detection equipment.
Measurement techniques are mostly visual. Older techniques, used teams of individuals who drove across every mile of pavement to be measured. Speeds were usually quite slow (on the order of 16 km/hr (10 mph)) and measurement was done visually. More current methods record pavement surface video images at highway speed using a specially equipped van (see Figures 9.8 and 9.9) that is outfitted with high resolution cameras. Evaluation is either done manually by playing the video back on specially designed workstations (see Figure 9.10) while trained crews rate the recorded road surface (see Figure 9.11) or automatically by computer software (see Figure 9.12). Advantages of these more current methods are (Sivaneswaran and Pierce, 2001):
|Figure 9.8: Washington State DOT Pavement Condition Rating Van||Figure 9.9: Inside a Pavement Condition
|Figure 9.10: Pavement Condition Rating
|Figure 9.11: Pavement Condition Rating Station|
Integrated analysis units can collect pavement surface distress data in the previously described manner as well as collect data on a variety of other characteristics at highway speeds such as:
WSDOT Surface Distress Measurement Method
Visual Method - Old
WSDOT used a visual method from 1969 to 1998 consisting of four 2-person teams that drove at 16 km/hr (10 mph) over the entire State road system (over 8,000 miles) every year and visually rated surface distress (Sivaneswaran and Pierce, 2001).
High-Speed Video Imaging