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

T. Falayi, F.N. Okonta, F. Ntuli

Research output: Contribution to journalArticle

3 Citations (Scopus)

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 °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. © 2016, RILEM.
Original languageEnglish
Pages (from-to)4881-4891
Number of pages11
JournalMaterials and Structures/Materiaux et Constructions
Volume49
Issue number11
DOIs
Publication statusPublished - 2016

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Coal Ash
Fly ash
Lime
Soils
Compressive strength
Composite materials
Silicic Acid
Road construction
Calcium silicate
Water absorption
lime
Hydrates
Pavements
Curing
Cations
Ion exchange
Moisture
Positive ions
Concretes
Liquids

Cite this

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title = "The geotechnical and microstructural properties of desilicated fly ash lime stabilised expansive soil",
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 °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. {\circledC} 2016, RILEM.",
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The geotechnical and microstructural properties of desilicated fly ash lime stabilised expansive soil. / Falayi, T.; Okonta, F.N.; Ntuli, F.

In: Materials and Structures/Materiaux et Constructions, Vol. 49, No. 11, 2016, p. 4881-4891.

Research output: Contribution to journalArticle

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