Ambient Cured Fly Ash Geopolymer Coatings for Concrete

Abstract

The reinforced concrete structures that support transport, energy and urban networks in developed countries are over half a century old, and are facing widespread deterioration. Geopolymers are an affordable class of materials that have promising applications in concrete structure coating, rehabilitation and sensing, due to their high chloride, sulphate, fire and freeze-thaw resistances and electrolytic conductivity. Work to date has, however, mainly focused on geopolymers that require curing at elevated temperatures, and this limits their ease of use in the field, particularly in cooler climates. Here, we outline a design process for fabricating ambient-cured fly ash geopolymer coatings for concrete substrates. Our technique is distinct from previous work as it requires no additional manufacturing steps or additives, both of which can bear significant costs. Our coatings were tested at varying humidities, and the impacts of mixing and application methods on coating integrity were compared using a combination of calorimetry, x-ray diffraction and image-processing techniques. This work could allow geopolymer coatings to become a more ubiquitous technique for updating ageing concrete infrastructure so that it can meet modern expectations of safety, and shifting requirements due to climate change.

Fly Ash Particle Size Effect on Pore Structure and Strength of Fly Ash Foamed Geopolymer

“…Apart from being used in the traditional building elds, FLA has been applied in di erent areas as a good raw material for the preparation of geopolymer [8][9][10][11][12]. For example, to prove the possibility of in-situ resource utilization of FLA, there are a good many scholars having done plenty of basic studies on this aspect [13][14][15], among which there is one proposing that y ash foamed geopolymer (FAFG) as back lling material can be an excellent combination of y ash consumption and coal mine re prevention [16,17]. e complex underground environment demands highly for some speci c properties of FAFG, mainly focusing on its pore structure and strength.…”

Factorial design approach to investigate the significance of factors on the fire resistant, compression and adhesion properties of geopolymer binder

“…Curing time was found to be not significant due probably to the initial binding condition during curing process. As the sample cured, tension in the capillary pores increase resulting in a volume reduction (shrinkage) and simultaneously binding to the substrate [16]. Further curing does not change the inter-chemical bonding between geopolymer binder and substrate.…”

Microscopic Study of the Concrete / Geopolymer Coating Interface

“…For this reason, the improvement of the concrete surface by layers formed by various types of geopolymers using clay-based materials has been searched [7][8][9][10][11]. Some experiments have been aimed at forming alkaliactivated coating from fly ash [12][13][14]. Surface coatings utilizing geopolymer-based materials (GbM) offer a new, quick and safe option for the repair of damaged concrete as verified by a previous experiment [11].…”