Fabric development in lime treated clay soils : Wild, S; Arabi, M; Ward, G L Ground EngngV22, N3, April 1989, P35–37

Abstract

A regeneration of interest in the use of lime stabilised clay soils for subgrade capping material in highway construction has led to renewed consideration of the physical changes involved. It has generally been held that the long-term development in strength of lime stabilised soil is due to a gradual increase in the degree of crystalline order. The author describes work on illite and lime, kaolinite and lime and montmorillonite and lime carried out at high temperatures and for periods of up to two years. The formation of a calcium silicate aluminate hydrate gel is described which also occurs at lower temperatures but at a slower rate. TEM micrographs show the gel which is also seen in a sample taken from the lime-stabilised foundations of a 400 year old bridge in Iran. The author suggests that stability comes from the gradual formation of the gel product and development of the gel-clay particle microstructure rather than from crystallisation of the gel. The effect on permeability and how this increases or decreases with age are considered.