The deflection of a flexible road pavement under a heavy wheel load moving at creep speed can be used to predict the future structural performance of the pavement and to design the strengthening of it by overlaying with bituminous materials. Equipment and procedures for its use as standardised for the measurement of deflection in the united kingdom are described in TRRL laboratory reports LR834 and LR835. The present report describes the adjustment of measured deflections to standard values suitable for design purposes and their use, together with the appropriate traffic data, for the prediction of remaining pavement life and for the design of overlay thickness. The technique sometimes requires information from cores and trial holes to allow the appropriate decisions for a particular pavement to be made. Matching practical strengthening measures to the variation in structural strength, as reflected by deflection measurements, along the length of any road requires a statistical approach. Methods of analysing deflection data are presented and procedures recommended for both manual and computer processing. (Author/publisher)
Abstract