Modelling of the stress state and deformations of APT tests

The permanent deformations of unbound materials in low-volume roads have been studied at VTT with two different accelerated pavement tests (APT). The tested structures consisted of different subgrades, layer thicknesses, water contents and pavement materials. The permanent deformations and dynamic responses of various materials were measured both in the vertical and horizontal directions during the tests. The deformation and strength properties of materials were also studied in the laboratory to get reference information. The common objective for these APT was to determine where permanent deformations happen and which factors control the development of permanent deformation. Even though the structures had many similarities, the permanent deformations occurring in the tests concentrated in different layers: in the low-volume test it was in the base layer and in the spring-overload test in the subgrade. The APT tests were modelled with FEM calculations. The primary aim of these FEM calculations was to get a deeper understanding of why permanent deformations happen in different parts of the pavement. The secondary aim was to find out which is the best way to model stresses. A common way to model a wheel load is to model it as an axisymmetric case with static loading. The best material model for a realistic stress distribution proved to be Mohr-Coulomb's material model. The simple linear elastic model without tension-cut-off property gives high tensile stresses in cases where asphalt layers are thin. The linear elastic material model with tension-cut-off gives better, but not totally acceptable stresses. By using Mohr-Coulomb material model the most sensitive materials and layers for permanent deformations were reliably discovered.

• Authors:
  • Korkiala-Tanttu, L
  • Laaksonen, R
• Conference:
  • International Conference on Accelerated Pavement Testing, 2nd, 2004, Minneapolis, Minnesota, USA
• Publication Date: 2004

Language

• English

Media Info

• Pagination: 23p
• Monograph Title: Full scale accelerated pavement testing: a southern hemisphere and Asian perspective

Subject/Index Terms

• TRT Terms: Accelerated tests; Deformation; Finite element method; Gravel roads; Low volume roads; Mathematical models; Pavements; Properties of materials; Strength of materials; Tests for suitability, service and quality; Unpaved roads
• ATRI Terms: Accelerated testing; Deformation; Finite element method; Low traffic road; Material properties; Modelling; Pavement testing; Strength; Unsealed road
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 01389245
• Record Type: Publication
• Source Agency: ARRB
• Files: ITRD, ATRI
• Created Date: Aug 23 2012 3:16AM