EXPERIMENTAL STUDY ON GEOPOLYMER CONCRETE USING LOW- CALCIUM FLY ASH

Abstract

Geopolymer concrete is gaining recognition as an eco-friendly alternative to traditional Portland cement concrete due to its low carbon footprint, utilization of industrial byproducts, and potential for high performance in construction applications. One of the key materials in geopolymer concrete is fly ash, a fine powder residue produced during the combustion of coal in power plants. Fly ash can be categorized into two types based on its chemical composition: high-calcium (Class C) and low-calcium (Class F). The study begins with the preparation of geopolymer concrete mixes using low-calcium fly ash as the sole source of alumino-silicate material. A mix design is developed where low-calcium fly ash is activated with an alkaline solution of sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃), which facilitates the formation of a geopolymeric binder. The study examines various mix proportions to optimize the strength and workability of the concrete. Key parameters such as the molar concentration of the alkaline solution, the ratio of sodium silicate to sodium hydroxide, and the curing conditions are varied to determine their influence on the final properties of the geopolymer concrete. After rigorous study the results. obtained are: Compressive strength test results are 18.25 MPa after 7 days of curing and 26.72 MPa after 28 days of curing, water absorption test results are 1.8% for 7 days and 1.5% for 28 days, after conducting workability test (Compaction factor test) based on test results Geopolymer concrete falls under the "good workability "category