A pavement scheduled for an overlay of 76 mm (3 inches) of asphaltic concrete on one half the project and 178 mm (7 inches) on the other half was tested and evaluated at two sites for each thickness of overlay. Precise elevations were obtained on 0.305-m (1-foot) intervals across the pavement. The Road Rater and Benkelman beam were used to determine the in-place behavior of the pavement before and after construction of the overlay. Prior to placement of the overlay, the pavements were cured to determine actual layer thicknesses, and in-place CBR tests were performed to determine actual subgrade conditions.

Analysis of Road Rater deflections permitted determination of the "effective'' thickness of the old existing pavement in terms of the actual thickness of the crushed stone base and an equivalent thickness of asphaltic concrete of "reference" quality materials. Three months after the overlay had been constructed, the test sites were revisited, Road Rater tests made, and precise levels determined on 0.305-m (1-foot) intervals across the pavement. Thus, actual overlay thicknesses could be determined. Analysis of the Road Rater deflections confirmed the overlay thicknesses.

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The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky, of the Kentucky Department of Transportation, nor of the Federal Highway Administration, This report doe not constitute a standard, specification, or regulation.

Prepared for the International Symposium on Bearing Capacity of Road and Airfields (Trondheim, Norway: June 23-25, 1982).