Design of Overlays Based on Pavement Condition,Roughness,and Deflections. Part 1. Tentative Method for Overlay Design Based on Visual Pavement Distress.

摘要

Data collected on 111interstate highway projects in Virginia were analyzed by multiregression analysis and the rating coefficient for each type of distress determined. By this means,the total pavement distress and,hence,the maintenance rating of each pavement was obtained. The types of distress that were found to influence the maintenance rating were longitudinal cracking, alligator cracking,rutting,pushing, ravelling,and patching. Then, a method for designing the required thickness of overlays was developed based on taking the thickness equivalency of an asphaltic concrete overlay in Virginia as equal to 0.5 (the thickness equivalency of an asphaltic concrete for new construction is 1.0) and the overlay thickness as a function of the ratio of the traffic,in terms of 18-kip (8, 160kg) equivalents,carried by the pavement before the overlay to the traffic it would carry after the overlay,depending on the durability of the asphaltic mix. This design method does not require the use of a deflection measuring device.