International Journal of Advanced Engineering Application

Mechanical Performance and Durability of Geopolymer Concrete Incorporating Fly Ash and Ground Granulated Blast Furnace Slag as Alkali-Activated Binders

Author(s):Rajesh Venkataraman, Priya Subramaniam, Anand Krishnaswamy

Affiliation: Department of Civil and Environmental Engineering, Indian Institute of Technology Hyderabad, Telangana, India

Page No: 56-61

Volume issue & Publishing Year: Volume 3, Issue 6, 2026/06/09

Journal: International Journal of Advanced Engineering Application (IJAEA)

ISSN NO: 3048-6807

DOI:

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Abstract:
Geopolymer concrete (GPC), produced by alkali activation of aluminosilicate-rich industrial by-products without Ordinary Portland Cement (OPC), offers a viable pathway to near-zero-clinker structural concrete with embodied CO₂ reductions of 40–80% relative to OPC-based systems. This study investigates binary geopolymer binder systems combining Class F Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBS) at varying mass ratios (FA:GGBS = 100:0, 70:30, 50:50, 30:70, 0:100) activated by a 10M NaOH + sodium silicate (Ms = 2.5) alkaline solution under ambient curing at 30±2°C. Properties evaluated include workability, setting behaviour, compressive strength at 7/28/90 days, flexural and split tensile strength, rapid chloride permeability (RCPT), water absorption, reinforced beam load-deflection response, Mercury Intrusion Porosimetry (MIP) evolution at 3–90 days, and SEM/EDX microstructural analysis. The 50%FA+50%GGBS blend (GPC-FA50) achieves 90-day compressive strength of 48.3 MPa, chloride permeability of 276 C (ASTM C1202 ‘Very Low’), and embodied CO₂ of 187 kg/m³ — a 54% reduction versus OPC control — identifying it as the optimal mix on the integrated strength-durability-carbon trade-off frontier. SEM confirms a dense, crack-free aluminosilicate gel matrix; EDX Al/Si ratios of 0.61 are consistent with co-formation of N–A–S–H and C–A–S–H gels in GGBS-containing blends.

Keywords: geopolymer concrete, fly ash, GGBS, alkali activation, compressive strength, chloride permeability, SEM, EDX, embodied carbon, M25 equivalent

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