Stabilised sub-bases in road foundations: structural assessment and benefits

Document Status

Current

Supplement

Civil & Structural Supplement

Series

Report

Abstract

At present, the Department of Transport limits stabilised sub-bases to cement bound materials of strength no lower than Type CBM1 and requires these materials to be built to the same thickness as unbound granular, Type 1 sub-base. Research aimed at widening the permissible range of stabilised materials and determining economical foundation designs for these materials has been carried out. The stabilised materials examined were cement bound granular materials comprised of crushed rock and sand and a cohesive soil that was initially treated with lime and then cement. This report describes the mix designs of the stabilised materials to produce low strength and high strength versions for both the cement bound granular materials and the cement bound, lime treated soil. The production of these sub-base materials is described together with their method of construction at full scale, on a weak clay subgrade of CBR between 2. 5 and 3%. An unbound granular, Type 1 sub-base was also constructed as a control material. The performance of the stabilised sub-bases, under wheel loads representative of construction traffic, was compared to that of the unbound granular, Type 1 sub-base. Laboratory tests also determined the structural properties of stiffness and strength of the sub-base materials and the dependence of these properties on their age.

Author

Chaddock, B. C. J. and Atkinson, V. M.

History

This document is no longer available from the original publisher, therefore the status is unconfirmed.

Subjects

• Roads
• Civil engineering, infrastructure and public utilities
• Transport facilities
• Road pavement

Publisher History

The Transport Research Laboratory (TRL) is an internationally recognised organisation providing research, consultancy, testing and certification for all aspects of transport.