Proof-of-concept of alkali-activated treatment of residual Bringelly shale

Abstract

Bringelly shale, which covers extensive parts of the Sydney region, contains up to 55% clay minerals including up to 40% of the reactive illite-smectite minerals (William and Airey, 2005). The residual by-product derived from the weathering of Bringelly shale occupies the shallow layer near the ground surface that is often encountered or exposed during construction activities. Due to the presence of expansive clay-water interlayers in the smectite minerals, residual Bringelly Shale (RBS) can have high swelling potential, which is deleterious to pavement and structures founded on them. Traditional soil stabilisation uses lime and cement to improve the engineering properties and mitigate the volume change behaviour of expansive soils. Alkali-activated stabilisation of expansive soil on the other hand is a recent concept seen as a key alternative to lime and cement-based treatment. Alkali-activated treatment also aligns with the construction industry’s effort to develop new and sustainable low carbon technologies to reduce the impact of carbon footprint from the industry. There are few reports of alkali-activated soil stabilisation studies in literature, those that have mainly report on the use of an alkali to activate a precursor such as metakaolin or fly ash to develop geopolymer binders to strengthen the soil. Even fewer studies, perhaps one or two to the best of the author’s knowledge, have investigated alkali-activated treatment of expansive soil (not on expansive minerals to develop geopolymer binders). Therefore, the main purpose and significance of this research is to investigate whether alkali-activated treatment of RBS can be proven effective for volume stabilisation.

Date of Thesis submission	2019
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Chin Leo (Supervisor), Samanthika Liyanapathirana (Supervisor) & Zhu Pan (Supervisor)