Deformation characteristics of base and subbase layers under monotonic and cyclic loading

Abstract EN

Base and Sub base layers are considered as the platform for distributing the different applied stresses in flexible pavements.

The two layers must provide sufficient strength to resist any excessive generated deformation to achieve this goal, proper compaction machinery is essential to reach the required degree of compaction.

The present paper investigates the influence of degree of compaction of the base and Sub base layers on the generated deformation under the action of both monotonic and cyclic loadings.

Model tests were performed by compacting beds of base and Sub base layers to relative densities of 65 %, 77 % and 88 %, inside steel container of dimensions 1000mm* 750 mm* 750 mm.

The final thicknesses of the base and Sub base layers were 150mm and 350mm respectively A circular model footing of diameter 175mm : equivalent to 24194 mm tire contact area is placed on the base layer and subjected to a series of monotonic and cyclic loadings.

The results of monotonic tests revealed an increase of 71 % and 107 % in the carrying capacity when the relative density increased from 65 % to 77 % and from 65 % to 88 % respectively.

The cyclic tests revealed a substantial increase in the number of cycles at any stress level as the relative density increases from 65 % to 77 % and from 65 % to 88 %.