The geotechnical and microstructural properties of desilicated fly ash lime stabilised expansive soil

Journal article

Authors/Editors

Ntuli, Freeman

Research Areas

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Publication Details

Author list: Falayi T, Okonta FN, Ntuli F

Publisher: Springer

Place: DORDRECHT

Publication year: 2016

Journal: Materials and Structures (1359-5997)

Journal acronym: MATER STRUCT

Volume number: 49

Issue number: 11

Start page: 4881

End page: 4891

Number of pages: 11

ISSN: 1359-5997

eISSN: 1871-6873

Languages: English-Great Britain (EN-GB)

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Abstract

This study presents the use of marginal material as a stabiliser for expansive soil and therefore provides opportunity for high volume use of waste material for low cost, low volume road construction. Desilicated fly ash (DFA) was stabilised with lime up to 40 %. The effect of composite moisture content, lime content and curing temperature was studied. A 70:30 DFA:lime composite cured at 80 A degrees C for 96 h had the highest unconfined compressive strength (UCS) of 8.57 MPa, a 19.5 % water absorption after a 24 h soak with a corresponding 23.5 % reduction in UCS. The green composite (70:30) was then used to stabilise expansive soil. Expansive soil stabilised with 30 % 70:30 DFA: lime composite was found to have a UCS of 4.1 MPa and resulted in a 50.1 % reduction in the liquid limit and a 15.1 meq/100 g reduction in cation exchange capacity of the soil. The formation of calcium silicate hydrate and tricalcium aluminate in the expansive soil was responsible for the strength gain in the stabilised soil. The stabilised soil met the minimum requirements for the American Concrete institute's requirements for rigid pavement layers.

Keywords

Cation exchange capacity, Desilcated fly ash, Durability, Hydration, Saturation coefficient

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