Verification of stiffness modulus of road bases and sub-bases

The results of a study on the development and applicability of the Light Weight Deflectometer (LWD) and Falling Weight Deflectometer (FWD) for the verification of the quality of bearing capacity of road bases and sub-bases are presented. Relationships have been developed between the hearing capacity and stiffness moduli of base courses and sub­bases and the stage of completion of the road. In any pavement design assumptions are made for the stiffness moduli of all constituent layers. The stiffness of a sand sub-base for example may be set to a value of 100 MPa. After construction of this sand sub-base an LWD test may provide data on the stiffness of the layer. This stiffness will be lower than used in the pavement design. Differences in load spreading and confinement in each construction stage may be the predominant causes. A model has been developed to assess how the lower seated layers stiffen with each extra layer, both due to overburden stress and changes of load spreading. The model is easy-to-use and does not require complicated stress dependency characteristics although these characteristics have been used in the development of the tool. The model can be used to assess the current stiffness modulus but also to predict whether the targeted design stiffness will be achieved. The paper addresses the development of the tool, the use of it in quality control and the predictive accuracy.

Language

  • English

Media Info

  • Pagination: pp 787-795
  • Monograph Title: Bearing capacity of roads, railways and airfields: proceedings of the ninth International Conference on the Bearing Capacity of Roads, Railways and Airfields: Trondheim, Norway 25-27 June 2013. Vol 1-2

Subject/Index Terms

Filing Info

  • Accession Number: 01596575
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • ISBN: 9788232102853
  • Files: ITRD, VTI
  • Created Date: Apr 21 2016 12:33PM