Distress Identification Manual
Accurate, consistent and repeatable distress evaluation surveys can be performed by using the Distress Identification Manual for the Long-Term Pavement Performance Program. Color photographs and drawings illustrate the distresses found in the three basic pavement type; asphalt concrete-surfaced; jointed (plain and reinforced) Portland cement concrete; and continuously reinforced concrete. Drawings of the distress types provide a reference to assess their severity. Methods for measuring the size of distresses and for assigning severity levels are given. The manual also describes how to conduct the distress survey, from obtaining traffic control to measuring the cracks in the pavement. Sample forms for recording and reporting the date are included. The manual also tells how to calibrate and operate fault measurement devices.
A light version of the LTPP Distress Identification Manual is also available through the LTPP InfoPave Mobile app, suitable for use in the field.
The LTPP Directive D-68 documents the changes made to the Distress Identification Manual for the Long-Term Pavement Performance Program.
Hard copy versions of the LTPP Distress Identification Manual and the pocket guides are no longer available. The pocket guides may be downloaded using the links below.
Download DIM: Asphalt Concrete Pavements
Download DIM: Jointed PC Concrete Pavements
Download DIM: Continuously Reinforced Concrete Pavements