Welcome Benkelman Beam (BBD) test
1. SCOPE This test procedure covers the determination of the rebound deflection off a pavement under a standard wheel load and tyre pressure, with or without temperature measurements.
2. EQUIPMENT
Basic equipment shall consist of:
(a) A Benkelman beam to the Ministry of Works and Development pattern having the dimensions . The beam must be fitted with a satisfactory locking device designed to secure the beam when moving to a new site and a suitable vibrator mounted at the
pivot point. In sunny weather the beam may pass from shade into sunshine as the vehicle moves away. Therefore a shield similar to that described in Road Research Unit Newsletter No 49 should be used. TNZ T/1 June 1977 SP/ST1:77XXXX STANDARD
TEST PROCEDURE FOR BENKELMAN BEAM DEFLECTION MEASUREMENTS.
(b) A truck or trailer with an axle load of 8.20 ±0.15 tonnes equally distributed on two dual tyred wheels operating at the inflation pressure necessary to give a tyre contact area of 0.048 ± 0.0002 m2 . * The tyres shall preferably be 10.00 x 20, 12 ply
with tubes and rib treads.
(b) A truck or trailer with an axle load of 8.20 ±0.15 tonnes equally distributed on two dual tyred wheels operating at the inflation pressure necessary to give a tyre contact area of 0.048 ± 0.0002 m2 . * The tyres shall preferably be 10.00 x 20, 12 ply
with tubes and rib treads.
(c) A tyre pressure gauge graduated in 20 Kpa divisions or smaller.
(d) A thermometer with a range of 0-6°C in 1°C divisions.
(e) A mandrel suitable for making a 100mm deep hole in the pavement for insertingthe thermometer. The diameter of the hole should be 13mm.
(f) A can containing either glycerol or oil for filling the thermometer hole
