Spent Coffee Grounds–Fly Ash Geopolymer Used as an Embankment Structural Fill Material

Abstract

AbstractThe drinking of coffee forms a deep-rooted pastime in many communities worldwide. However, the culture of coffee drinking generates vast quantities of organic waste that ends up in landfills. Current research trends are inclined towards recycling of waste materials into alternative construction materials, hence the need to research sustainable uses for spent coffee grounds. Coffee grounds (CG) are highly organic with a very high percentage of biodegradable material. The objective of this research was to study the strength development of CG when used as a geopolymer stabilized embankment structural fill material aiming for a better understanding of geopolymer stabilization of highly organic material. Fly ash (FA), being a silica and alumina rich material, was used as a precursor. A liquid alkaline activator, L, being a sodium hydroxide-sodium silicate solution was used for alkali activation of FA in the CG-FA geopolymer. Factors found to affect strength development of the CG-FA geopolymer were: (1)...