Falling Weight Deflectometer

FWD is a trailer mounted dynamic impulse loading device which can be towed by any suitable towing vehicle and is used for non destructive testing of pavements.

The outputs from FWD are:

  • Deflection bowl (Transient Deflections at seven different points, spaced 300 mm apart)
  • Back Calculated Layer Moduli
  • Overlay design
  • Remaining/Residual life of the pavement
  • k-value
  • Load transfer efficacy
  • Pavement Classification Number (PCN) value
  • Stresses/strains

The unique features of FWD are:

  • Follows largely the mechanistic approach
  • Enables design/evaluation based on fundamental material properties
  • Loads pavements dynamically and simulates actual traffic loading and loading duration
  • Back calculated layer moduli computed from deflection measurements are nearly representative of the field conditions