USE OF THE FALLING WEIGHT DEFLECTOMETER FOR THE STRUCTURAL EVALUATION OF PAVEMENTS WITH CEMENT TREATED BASES . 5TH CONFERENCE ON ASPHALT PAVEMENTS FOR SOUTHERN AFRICA (CAPSA 89). PROCEEDINGS HELD IN SWAZILAND, 5-9 JUNE, 1989

The Falling Weight Deflectometer (FWD) is a powerful tool for assisting with the structural evaluation of all pavement types. It allows realistic loading to be applied and an accurate measure of the deflected pavement surface to be made. Knowing the layer thicknesses and by using elastic theory, the effective elastic stiffnes of each pavement layer can be computed. This, together with information from coring and pitting (if possible), provides a basis to assess the remaining pavement life and, if necessary, to design appropriate remedial work. In contrast, the FWD is non-destructive, except for the need to take cores, produces a very accurate measurement of the "deflection bowl" and is quick and easy to operate. Against a background knowledge of the deterioration of effective stiffnesses of pavements with cement treated layers, with trafficking, stiffnesses determined from FWD testing can be readily interpreted. Procedures for using the FWD in pavements with cement treated bases are described in which the incidence of primary (shrinkage) cracking is firstly identified in order to avoid confusion in the interpretation of deflection surveys. The techniques for presentation of deflection data are presented using measurements from a typical UK job by way of illustration. The "back-analysis" technique is outlined, showing the importance of non-linear behaviour in soils and granular materials. Results from a case study are used to show the range of effective stiffnesses which can be exhibited by cement treated bases. The procedure for design of remedial work is also outlined. The overall philosophy is one of providing improved techniques by which a more accurate assessment of pavements can be made. This then enables rehabilitation, within the framework of mechanistic design principles, allied to experience and a knowledge of pavement material behaviour.(A) For the covering abstract of the conference see IRRD 828827.

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  • Corporate Authors:

    CAPSA

    PO BOX 993
    Manzini,   Swaziland 
  • Authors:
    • Brunton, J M
    • BROWN, S F
    • ARMITAGE, R J
  • Publication Date: 1989

Language

  • English

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Filing Info

  • Accession Number: 00604017
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • ISBN: 0-620-14395-9
  • Files: ITRD, TRIS
  • Created Date: Feb 28 1991 12:00AM