Citation

Douglas RA. Proc. Inst. Civ. Eng. Transp. 1997; 123(3): 163-173.

Copyright

(Copyright © 1997, Institution of Civil Engineers, Publisher ICE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The paper describes tests undertaken to investigate the behaviour of unbound roads subjected to heavy wheel loads using low tyre inflation pressures. It is hoped that the research will aid in the development of procedures for the design of unbound roads used by vehicles equipped with central tyre inflation (CTI) systems, Full scale trafficking tests were carried out in the Transport Research Laboratory's Pavement Test Facility at Crowthorne, Berkshire, Test roads consisted of a single layer of granular material placed on a Gault clay subgrade, The roads had base thicknesses of 200, 350 and 560 mm. Wheel loads of 44 and 80 kN were used, in combination with tyre inflation pressures of 345 and 690 kPa. Up to 10 000 passes were made on each of six test road sections. In phase I of the tests, rut depths were observed and falling weight deflectometer (FWD) deflections were recorded as a function of the number of passes, In phase II, shallow dynamic subgrade strains were recorded. Analyses of the rutting, FWD tests and shallow dynamic subgrade strain behaviour are presented, leading to the general conclusion that the benefits of reduced tyre inflation pressure traffic seen in field implementations of CTI systems are derived more from the behaviour of the granular base than the subgrade.

Language: en