Study on Physical and Mechanical Properties of Fly ash Based Geopolymer Concrete

The growing environmental concerns associated with the cement industry, particularly its high carbon dioxide emissions and energy-intensive production processes, have accelerated the search for sustainable construction materials. Simultaneously, the large-scale generation and disposal of fly ash from thermal power plants pose significant environmental challenges. Geopolymer concrete (GPC), produced using alumino-silicate materials such as fly ash, has emerged as a promising alternative to conventional Portland cement concrete due to its reduced carbon footprint and effective utilization of industrial by-products. However, the widespread application of GPC is constrained by its dependence on heat curing, which limits its suitability for cast-in-situ construction. This study investigates the development of ambient-cured geopolymer concrete composites (GPCC) and evaluates the influence of fly ash content on their physical and mechanical properties. An extensive experimental program was conducted, including the assessment of fresh and hardened concrete characteristics and the flexural behavior of reinforced GPCC beams. The results indicated that conventional ambient-cured GPC exhibited delayed setting, requiring nearly three days for hardening. To overcome this limitation, 10% fly ash was replaced with ordinary Portland cement (OPC), resulting in GPCC with improved setting characteristics and enhanced early-age strength without the need for heat curing. The findings demonstrate the feasibility of ambient-cured GPCC as a sustainable and practical construction material for structural applications.