FIELD TESTING OF AASHTO PAVEMENT OVERLAY DESIGN PROCEDURES (WITH DISCUSSION AND CLOSURE)

The AASHTO pavement overlay design procedures were recently revised to make them easier to use, more adaptable to calibration by local agencies, and more comprehensive. The revised procedures were extensively field tested using data from many actual in-service pavements located throughout the United States. A total of 74 examples were developed for seven different categories of overlay and pavement types. State highway agency personnel provided the design, traffic, condition, and deflection data for the overlay design examples and participated in the development of the examples. The revised AASHTO overlay design procedures produce reasonable overlay thicknesses that are consistent with state highway agency recommendations. The examples illustrate the importance of selecting appropriate inputs for overlay design, the use of nondestructive testing data and condition data in overlay design, the significance of design reliability level to overlay thickness, and the importance of preoverlay repair.