NON-DESTRUCTIVE TESTING OF METALLED ROADS IN SENEGAL BY MEANS OF THE DEFLECTOGRAPH. TRAFFIC-DEFLECTION RELATION, EVOLUTION IN DEFLECTION AS A FUNCTION OF TRAFFIC

AUSCULTATION PAR LA METHODE DEFLECTOMETRIQUE DE CHAUSSEES REVETUES AU SENEGAL - RELATION TRAFIC-DEFLEXION, EVOLUTION DE LA DEFLEXION EN FONCTION DU TRAFIC

As part of a strengthening programme concerning flexible pavements, the directorate of public works in senegal launched a campaign for the non-destructive testing of pavements with deflectographs, in order to determine which sections of the network had to be strengthened. In general, low-cost roads in senegal consisting of a gravel-laterite roadbase resting directly over in-situ soil and surfaced with a two-course carpet, behaved satisfactorily under heavy vehicle traffic between 300000 and 4000000. This satisfactory behaviour is due to the very high quality of the subgrade consisting of sand with a low clay or silt content, the bearing capacity of which exceeds 15. The deflection measurements were taken according to the recommendations laid out in the manual for the study of the strengthening of metalled roads in tropical Africa and madagascar, prepared by the c.e.b.t.p. The measurements helped towards modifying the hypothesis put forward in the manual, which did not distinguish permissible deflections at the limit of the elastic phase between clayey and sandy soils. Thus the permissible traffic-deflection curve was modified and provisionally adapted to sandy roads with low deformability as encountered in senegal. This measurement campaign also showed the evolution in deflection as A function of traffic for similar pavement structures subjected to similar traffic flow over a 20-year period. An increase in deflection as a function of traffic of approximately 4/100 mm per year was observed during the first 15 years which represents the elastic phase, deflection increasing from that figure by approximately 16/100 per year. Therefore, the residual heavy vehicle traffic, which the pavement can withstand, will be determined taking into account the evolution in deflection during the elastic phase. This method of investigating the service life of a surfaced road could also be applied to other roads in tropical Africa designed according to the same criteria and having the same type of substratum. /TRRL/

  • Corporate Authors:

    Revue Generale des Routes

    9 rue Magellon
    Paris,   France 
  • Authors:
    • Durrieu, J
    • Liautaud, G A
    • Adam
  • Publication Date: 1973-3

Language

  • French

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00125318
  • Record Type: Publication
  • Source Agency: Laboratoire Central des Ponts et Chausees (LCPC)
  • Files: ITRD, TRIS
  • Created Date: Dec 3 1975 12:00AM