DESIGN CONCEPT OF UNBOUND GRANULAR LAYERS IN PAVEMENT CONSTRUCTIONS

In many countries traditional pavement design methods have more or less been empirical in nature. Nonetheless, there is a drive towards the development of more analytical design approaches because they allow alternative solutions to be readily compared and, thus, evaluated. The reliable measurement of representative material properties is a prerequisite for any successful analytical design methodology. These must be obtained from experimental investigations followed by appropriate mathematical characterization of the deformation behavior of both the bound and Unbound Granular Materials (UGMs) used in the pavement construction of the subgrade. For many thinly-surfaced pavements the principle failure mechanism of concern is the excessive plastic deformation of the UGM. This paper describes an analytical design method based on the shakedown approach that utilizes test results from the repeated load triaxial apparatus to establish the risk level of permanent deformations in the UGM-layer. In order to model the permanent and resilient deformation behavior of UGM-layers in pavement constructions the non-linear "DRESDEN" stress-strain relationship was used. The relationship was then implemented into a Finite Element Program (FENLAP) that was used to check, using a part of the German pavement design guidelines whether or not the critical shakedown stress level for the UGM-layer (between stable and unstable behavior) was exceeded using different UGMs (Sandy Gravel and Granodiorite) for the granular base layer. It was concluded that this method could provide a powerful material assessment and pavement design tool for unbound pavement bases.

Language

  • English

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Filing Info

  • Accession Number: 00964330
  • Record Type: Publication
  • ISBN: 087659229X
  • Files: TRIS, ATRI
  • Created Date: Oct 9 2003 12:00AM