Comparative Study of Strength Properties of Conventional and One-Part Geopolymer Binder

Abstract

The production of ordinary Portland cement (OPC) is a carbon-intensive process that generates significant amounts of carbon dioxide gas from the combustion of fossil fuels and the thermal decomposition of limestone. Overall, the cement industry is responsible for around 7% of global carbon dioxide emissions, which poses a considerable threat to the global climate due to its greenhouse effect. The recent advent of geopolymer shows great potential to reduce carbon footprints by utilising industrial by-products, such as fly ash and ground granulated blast-furnace slag (GGBS), and converting them into a binding material. Generally, geopolymer binders are made using alumina silicate compounds (fly ash and/or GGBS) and an alkali activator (combination of sodium silicate and sodium hydroxide solution) called "two-part geopolymer". Despite having superior engineering properties to conventional OPC concrete, geopolymer concrete has not been widely adopted in the concrete industry so far. The safety hazards in mixing and handling geopolymer concrete possessed by sodium hydroxide are one of the barriers to the adoption of geopolymer concrete. Replacing liquid sodium hydroxide with less hazardous alkali materials, such as sodium carbonate powder, makes the geopolymer binder less hazardous and easier to mix and handle than with liquid sodium hydroxide. Geopolymer binders made using alumina silicate compounds and alkali activator (combination of sodium silicate and sodium carbonate), all in powdered form, are called "one-part geopolymer". This paper investigates a comparison of fresh and hardened properties between OPC concrete and geopolymer concrete samples of M30 grade. Also compares the environmental and social impacts that may occur due to construction using ordinary concrete and geopolymer concrete, and their impacts by calculating the amount of ingredients required for the construction of the building.