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Coordinating, Developing, and Delivering Highway Transportation Innovations

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Publication Number:  FHWA-RD-96-176    Date:  January 1997
Publication Number: FHWA-RD-96-176
Date: January 1997


LTPP Materials Characterization Program: Resilient Modulus of Unbound Materials (LTPP Protocol P46) Laboratory Startup and Quality Control Procedure

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As part of the Federal Highway Administration's (FHWA) Long-Term Pavement Performance Program (LTPP) Materials Characterization effort, a quality control/quality assurance (QCIQA) program for the resilient modulus testing of unbound granular materials (LTPP Protocol P46) has been developed. The P46 resilient modulus test protocol was developed to ascertain the strength of pavement base, subbase, and subgrade materials. This test is performed at stress states that are comparable to in-situ pavement conditions. The resilient modulus testing generally regarded as a research~type procedure, has historically been performed in a university setting and on a relatively small number of samples. Because the modulus value derived from this testing process is a key parameter for pavement design, the test is being performed for the LTPP program in a production testing environment in what may be the largest single resilient modulus testing program ever undertaken. It is of paramount importance to provide the LTPP researchers with the highest quality data possible. As such, a quality control/quality assurance (QC/QA) procedure was developed to verify the ability of the laboratory equipment and personnel to perform P46 resilient modulus testing for the LTPP program. This report describes the procedure used by the FHWA to perform this verification process. The concepts and testing processes outlined in this report can be applied to many test procedures and a variety of test equipment. The implementation of this procedure in the FHWA LTPP contractor laboratories has had a great impact on achieving repeatable, reliable, high quality resilient modulus data for the LTPP program.

Charles Nemmers, Director

Office of Engineering, Research and Development



This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. This report does not constitute a standard, specification, or regulation.

The United States Government does not endorse products or manufacturers. Trade or manufacturers' names appear herein only because they are considered essential to the object of this document.



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