National Academies Press: OpenBook
« Previous: Acknowledgments
Suggested Citation:"Abstract." Transportation Research Board. 1997. NCHRP Web Doc 14 Laboratory Determination of Resilient Modulus for Flexible Pavement Design: Final Report. Washington, DC: The National Academies Press. doi: 10.17226/6353.

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

ABSTRACT Laboratory Determination of Resilient Modulus for Flexible Pavement Design Key Words: laboratory testing, test methods, resilient modulus, asphalt concrete, base, subgrade, diametral test, indirect tension test, repeated load biaxial test, unconfined test, specifications, aggregate, lime/flyash stabilization. Abstract: Extensive diametral repeated load tests were performed on asphalt concrete specimens. Extensive repeated load biaxial tests were perfo aped on base and subgrade materials. New resilient modulus test methods were developed for these materials and presented in the form of AASHTO type test procMures. The repeats load test is not easy to perform and must be carried out on a carefully calibrated testing system including using synthetic specimens. To minimize human errors, a fully automated, closed loop testing and data acquisition system should be used. For asphalt concrete, the SHRP EG diametral testing device should be employed to minimize rocking. A mountable extensometer provides less variance and hence better repeatability for resilient modulus measurement. Poisson's ratio can be evaluated using a surface mounted EVDT to measure vertical deformation and externally mounted EVDTs to determine horizontal deformation. The value of Poisson's ratio used to determine He resilient modulus has an important influence on its value. Poisson's ratio should be measured rather than assumed. To reliably determine resilient modulus, axial deformation of base and subgrade materials should be measured on the specimen using either an (~) optical extensometer, (2) non-contact proximity gages or (3) small EVDTs supported by lightweight clamps. The optical extensometer is highly recommended. For granular materials a vacuum biaxial test offers an excellent approach when an optical extensometer is used. An unconfined repeated load test is recommended for cohesive subgrade soils. For cohesive soils, bedding irregularities at specimen ends, specimen aging and soil structure must all be properly considered to obtain reliable resilient moduli. v I,

Next: Executive Summary »
NCHRP Web Doc 14 Laboratory Determination of Resilient Modulus for Flexible Pavement Design: Final Report Get This Book
MyNAP members save 10% online.
Login or Register to save!
  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook,'s online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!