Geopolymers as Alternative Sustainable Binders for Stabilisation of Clays—A Review

Abstract

The need to transit to greener options in soil stabilisation has revamped research on the use of industrial and agricultural by-products in order to cut down on the current carbon footprint from the use of ordinary Portland cement (OPC) and lime related binders for the treatment of problematic soils. This study is a review on the use of geopolymers constituted by alkali activation of several industrial wastes such as pulverised fuel ash (PFA), ground granulated blast furnace slag (GGBS), metakaolin (MK), glass powder (GP), palm oil fuel ash (POFA), silica fume (SF), rice husk ash (RHA), volcanic ash (VA), and marble powder (MP) for the stabilisation of weak clays. The performance of stabilised clays as subgrade and subbase materials for road pavement construction was evaluated by comparing the 7 day UCS of the treated clays with the strength requirement for stabilised materials as outlined in BS EN 16907-4. The result of the study shows that geopolymers can be employed in improving the engineering properties of problematic clays to meet practical applications. Strength improvement was observed in the stabilised clays with increased precursor content, molarity of alkaline activator, and curing period.

Thermodynamics of calcined clays used in cementitious binders: origin to service life considerations

“…Interested readers are referred to suitable review papers for alkaline activated binders on this topic. 101,102 While the nature of most kinetic models used in thermodynamic modeling has an empirical component, there is the desire in the research community to link these measurable "macro" scale effects to scientic questions on smaller scales, like the dissolution rate which may be complicated by solid solutions of clays utilised in practice. However, while there is no lack of literature on the dissolution of pure clay minerals in the geochemical domain, there are only a few articles tackling this topic for specically metakaolin in acidic environments or alkali activated binders.…”

Behaviour and Microstructural Characteristics of Lime-GGBS-Treated Kaolin Clay Contaminated with Gypsum

“…Furthermore, like other industrial and agricultural residues, the use of GGBS lessens the already heightened concerns of increasing landfill wastes synonymous with the production of the more common traditional calcium-based stabilisers (CBS). In addition, the use of GGBS is known to be advantageous as an eco-friendlier stabiliser with lower carbon-footprint than CBS [ 40 , 41 , 42 , 43 ].…”

Asses the Use of Calcium Carbide for Increasing Mechanical and Thermal Properties of Alkali Activated GGBFS-MK Precursor

“…This product is made from alkali-activated materials which are named scientifically (Geopolymer) [1]- [4]. Geopolymers are formed by using industrial wastes or byproducts to form a binder that resembles OPC and providing a similar function with environmental and technical benefits, reduction in CO2 emissions by 80-90% and resistance to fire and chemicals [5], [6]. OPC and geopolymer differ primarily in their manufacturing processes, OPC relies on a high-energy manufacturing method whereas Geopolymer uses materials with very low energy like fly ash, slag, and a small quantity of chemicals (alkali medium).…”