International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 07 | Jul 2025
p-ISSN: 2395-0072
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INFLUENCE OF MINERAL ADDITIVES ON THE FRESH AND MECHANICAL PROPERTIES OF GEOPOLYMER CONCRETE 1Pranshu Yadu, 2Anurag Wahane 1PG Scholar, 2Assistant Professor, Department of Civil Engineering, Shri Shankaracharya Institute of Professional
Management and Technology, Raipur (C.G.) ------------------------------------------------------------------------***---------------------------------------------------------------------Abstract: This study investigates the development of geopolymer concrete (GPC) using low-calcium (Class F) fly ash as the primary binder, with a focus on utilizing locally available materials suitable for ambient curing conditions. Multiple mix design approaches were explored to identify the most effective formulation for producing geopolymer concrete under local environmental conditions. The fresh properties of the prepared mixes were evaluated to assess workability and handling characteristics. Furthermore, compressive strength tests were conducted to compare the performance of different GPC formulations. The results demonstrate that with an optimized mix design, low-calcium fly ash-based GPC can achieve desirable mechanical properties and present an environmentally sustainable alternative to conventional concrete for structural applications.
Keywords: GPC, Low Calcium, Fly ash, Compressive, 1. Introduction The growing demand for sustainable construction materials has led to increased interest in geopolymer concrete (GPC) as a potential alternative to conventional Portland cement concrete. Geopolymer concrete, produced by activating aluminosilicate materials with alkaline solutions, offers significant environmental benefits by utilizing industrial by-products such as fly ash. Among these, low-calcium (Class F) fly ash is considered a suitable primary binder due to its favorable chemical composition for geopolymerization under ambient curing conditions. Several studies have explored different approaches for developing GPC using locally available materials to reduce dependency on imported resources and adapt to regional conditions. Research by Davidovits (1991) highlighted the environmental advantages of geopolymers, while subsequent works emphasized the influence of raw material selection, alkaline activator concentration, and curing methods on the performance of GPC. Hardjito and Rangan (2005) demonstrated that Class F fly ash-based GPC can achieve satisfactory mechanical properties when cured at ambient temperatures, making it practical for field applications. Fresh properties such as workability, setting time, and consistency are critical for ensuring the ease of placement and compaction of GPC. Studies indicate that mix design parameters, including activator ratio and aggregate selection, significantly impact these properties. Moreover, compressive strength remains the primary indicator of structural performance. Previous research has compared various geopolymer formulations, showing that optimized mix designs can achieve strength comparable to or even exceeding that of conventional concrete. In addition to technical performance, the economic feasibility of GPC is crucial for its practical adoption. Research comparing the cost of geopolymer concrete to traditional concrete reveals that while initial material costs may vary, the long-term environmental and durability benefits often offset these differences.
2. Research Objective To explore multiple approaches to develop geopolymer concrete using local materials and select the most suitable one. Design a low-calcium fly ash (Class F) based geopolymer mix that cures under ambient conditions. Assess fresh properties and compressive strength of different geopolymer concrete types.
3. Material & Methodology Fly ash: Fly ash primarily composed of silica (SiO₂) and alumina (Al₂O₃), is the key binder in geopolymer concrete. Class F fly ash, with low calcium content (CaO < 10%), is preferred for its superior long-term strength and durability. Typical chemical composition includes SiO₂ (50–60%), Al₂O₃ (20–30%), and Fe₂O₃ (5–10%). The fine particle size (mostly < 45 microns) enhances workability and reactivity. The amount of fly ash in the mix significantly influences the strength and setting properties of geopolymer concrete. Alkaline Liquid: It is typically a combination of sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃), activates the fly ash in geopolymer concrete. It dissolves silica and alumina, forming a binding alumino-silicate gel. The concentration of
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