AN EXPERIMENTAL APPROACH ON THE INFLUENCE OF ADDITIION OF METAKAOLIN ON THE PROPERTIES OF GEOPOLYMER CONCRETE

Abstract

Geopolymer concrete (GPC) is an innovative alternative to conventional Portland cement concrete, utilizing industrial by-products such as fly ash, slag, and metakaolin as primary binders. The use of metakaolin, a dehydroxylated clay, as an additive in geopolymer concrete has garnered significant attention due to its potential to enhance the mechanical and durability properties of the material. This experimental study investigates the influence of metakaolin addition on the properties of geopolymer concrete, focusing on workability, compressive strength, Split tensile strength, and durability performance.
A series of geopolymer concrete mixes were prepared by varying the percentage of metakaolin (ranging from 20% to 100%) by weight of the binder. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used as alkaline activators to synthesize the geopolymer paste. The fresh properties of the concrete, including workability and setting time, were assessed using standard test methods. Cured specimens were tested at different ages (7, 14, and 28 days) to evaluate their compressive strength, split tensile strength.
The experimental results revealed that the incorporation of metakaolin significantly improved the mechanical properties of geopolymer concrete, especially in terms of compressive and split tensile strength. The optimal metakaolin content was found to be around 80%, beyond which the strength gains plateaued or slightly decreased. The microstructural analysis indicated a denser and more cohesive gel matrix in metakaolin-blended samples, which enhanced the overall durability of the geopolymer concrete, including resistance to water absorption and chloride ion penetration.This study highlights the potential of metakaolin as an effective supplementary material to enhance the properties of geopolymer concrete, thus providing a more sustainable alternative to traditional cement-based concrete. The findings suggest that metakaolin not only improves the mechanical performance but also contributes to the environmental sustainability of geopolymer concrete by reducing the carbon footprint associated with cement production.