The correlation between the results from the two mechanisms is given in Fig.
9.3. The deflectograph and the Benkleman beam give similar but not identical
results, with the deflectograph giving lower readings. The results are reasonably
independent of temperature changes, within a range of 10°C to 30°C. The
relationship illustrated is derived from measurements of pavements with
rolled asphalt, bitumen macadam and tarmacadam surfacings, bitumen-bound,
cement-bound and crushed stone roadbases and subgrades with CBR values
between 2.5 and 15%