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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.

Title:

Development of a Catalog of Resilient Modulus Values for Aggregate Base for Use With the Mechanistic-Empirical Pavement Design Guide (MEPDG)
Authors:
M. Shabbir Hossain
M. Shabbir Hossain
D. Stephen Lane
D. Stephen Lane
Year: 2015
VTRC No.: 15-R13
Abstract: Base aggregate is one of the intermediate layers in a pavement system for both flexible and rigid surfaces. Characterization of base aggregate is necessary for pavement thickness design. Many transportation agencies, including the Virginia Department of Transportation, assign a layer coefficient for pavement design where consideration for gradation or rock type is not obvious. The mechanistic-empirical pavement design requires base aggregate to be characterized using a resilient modulus value. Therefore, 16 aggregates from different geophysical regions of Virginia were collected and tested for resilient modulus in order to develop a catalog for the implementation of the Mechanistic-Empirical Pavement Design Guide (MEPDG).

A wide range of resilient modulus values for base aggregate was found for different sources with different rock types. A catalog was developed with resilient modulus values for 16 aggregates from Virginia. The resilient modulus values ranged from approximately 10,000 to 30,000 psi. In general, limestone showed the higher modulus as compared to granite. An increase in compaction moisture content, even within allowable limits, adversely affected the resilient modulus value for many aggregates. This moisture sensitivity is related to both the percent of material passing the No. 200 sieve and the plastic nature of these fines. These values are recommended to be used as reference values for the MEPDG, but engineering judgment should be applied to account for moisture sensitivity.