Development of stabilisation and solidification in lime–clay mixes

Abstract

Two refined clay minerals, English China Clay (predominantly kaolinite) and Wyoming Bentonite (predominantly sodium-montmorillonite), were used to assess the time-dependent effects of mineral structural chemistry on the lime–clay reaction. The two clays, representing the extremes of structural negative charge development, were treated with two lime contents. Changes in the physico-chemistry of the samples were monitored after three curing periods by performing batch leaching tests and monitoring changes in undrained shear strength and Atterberg limits. The effects of changing the batch test operating parameters and increasing the curing period were assessed by measuring changes in solution pH and conductivity, and by analysis of eight elements in solution. The solidification mechanisms due to lime addition were found to be different for the two minerals. Pozzolanic reactions involving English China Clay and Wyoming Bentonite were found to occur owing to the dissolution of aluminium and silicon from the respective mineral. Development of the batch leaching test showed that changing the operational parameters had no effect on the observed trends associated with the time-dependent modification and solidification reactions. It was also shown that successful solidification could be monitored using simple conductivity measurements without the need for extensive and complex elemental analysis.

The role of curing period on the engineering characteristics of a cement-stabilized soil

“…Such behavior could be attributed to the fact that the formation of reaction products close to clay particles impedes the penetration of additional lime. The relationships between curing time and UCS are not always linear, since strengths after a long curing period are arisen due to the development of crystals, rather than the immediate lime reaction [15,16].…”

Variations in strength of lime-treated soft clays

“…There has been cumulatively a large amount of laboratory and site investigation of the behaviour of soils treated in this way, but there are few systematic and theoretical studies of the mechanical properties of lime-treated soft clay that are applicable to practical problems (e.g. Boardman et al, 2001;Horpibulsuk et al, 2010;Liu et al, , 2010Locat et al, 1996;Suebsuk et al, 2010Suebsuk et al, , 2011. The lime stabilisation leads to a rise in the pH of the pore water and dissolution of the silica and alumina from the clay, in a manner similar to the reaction between a weak acid and strong base.…”

Mechanical Behaviour of Soil Improved by Alkali Activated Binders

“…The use of traditional binders such as lime and cement has a strong impact on the physical and hydro-mechanical properties of soils as results of short and long term reactions which take place after the treatment [1][2][3][4][5][6][7][8][9].…”