DefinePK

Abstract

The search for environmentally friendly construction materials with durability comparable to ancient concrete has spurred significant interest in alkali-activated cementitious systems over the past two decades, leading to the development of Geopolymer Concrete (GPC). This study focuses on the development of geopolymer mixes using various proportions of fly ash and Ground Granulated Blast Furnace Slag (GGBS), and investigates their mechanical properties. A comprehensive literature review on the mechanical and durability aspects of geopolymer concrete has also been conducted.
In this research, the ratio of sodium hydroxide (NaOH) to sodium silicate was maintained at 1:2 for all mixes, while the alkaline liquid-to-binder ratio was fixed at 0.70. However, the concentration of sodium hydroxide solution was varied as 6M, 4M, and 3M. Three mix designs were prepared—F75G25, F50G50, and F25G75—where "F" and "G" represent fly ash and GGBS, respectively, and the numerical value indicates the percentage of fly ash replaced by GGBS. These mixes were prepared in the AML Laboratory at CSIR-SERC, Chennai. Ambient curing at room temperature was adopted for all specimens.
Compressive strength was measured at 3, 7, and 28 days. Results indicated that the compressive strength of geopolymer concrete increased with a higher percentage of GGBS in the mix. Notably, the mix F25G75, with 75% GGBS and 25% fly ash, achieved the highest compressive strength at a NaOH concentration of 3M. Additionally, leaching in geopolymer concrete was found to decrease with increasing GGBS content.
Overall, geopolymer concrete demonstrates relatively higher strength and improved durability characteristics, making it a promising sustainable alternative to conventional Portland cement concrete.