An Evaluation of the Effectiveness of S-5 Scratch Courses

Report No: 77-R27

Published in 1976

About the report:

A study was made of the practice of "scratching" the surface course of several new construction projects in Virginia. It was found that sections with the surface course placed in one lift produced a road roughness value of about 3 in./mile higher than comparable sections which had the surface course split. Conversely, the single lift surface course sections had almost 2% average lower void contents than the scratched sections. It is concluded that the better riding quality cannot be justified economically when the decrease in durability caused by the lower density is considered.

Disclaimer Statement:The contents of this report reflect the views of the author(s), who is 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 Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


  • Charles S. Hughes, P.E.

Last updated: January 28, 2024

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