Further Investigations Towards a Rational Method of Design for Flexible Pavements.

A finite-element program has been developed to the stage that, given adequate material characterization, it may be used to analyse the effect of passing wheel loads on any proposed pavement structure. Until now such programs have examined the induced stresses and transient deflections of the pavement system. This program has the capability to predict the permanent strain accruing in any element of the pavement. It will then take these values and produce the surface profile of the pavement after any specified number of wheel loads has passed. To further this work a laboratory pavement simulator has been used to obtain load-deformation-time data for the program. Also the concepts of threshold and critical stresses to permanent deformation prediction have been examined together with two creep laws for boulder clays.