International Journal of Urban Management and Energy Sustainability

International Journal of Urban Management and Energy Sustainability

Enhancing The Mechanical Properties of Eco-Friendly GGBS-Based Geopolymer Concrete Through Combined Effects of Fibers and Nanosilica

Document Type : Case Study

Authors
Hooman Nikkhah Khajeh Ataei 1
Alireza Lork 2
Bahman Salami 3
1 Department of civil engineering, KI.C., Islamic Azad University, Kish, Iran
2 Department of Civil Engineering, Ka.C., Islamic Azad University, Karaj, Iran
3 Department of Civil Engineering, ST.C, Islamic Azad University, Tehran, Iran
10.22034/ijumes.2026.743761
Abstract
Geopolymer concrete produced from industrial by-products is a promising low-carbon alternative to Portland cement concrete, but its brittle behavior and limited tensile resistance restrict its structural use. This study investigates the combined effects of nanosilica and alkali-resistant glass fibers on the mechanical performance of ground granulated blast furnace slag-based geopolymer concrete. Sixteen mixtures were prepared with a constant GGBS content of 500 kg/m³ and an activator of 12 M sodium hydroxide and sodium silicate: a reference mixture and 15 mixtures combining five NS contents with three AR glass fiber dosages. Specimens were cured at ambient temperature, and compressive and splitting tensile strengths were determined at 7, 28, 56 and 180 days. Both properties depended non-linearly on the two constituents, showing an optimum rather than a continuously increasing relationship, with strength declining beyond 2% NS and 0.6% fibers. The mixture containing 2% NS and 0.6% AR glass fibers performed best at all ages, reaching estimated 28-day compressive and splitting tensile strengths of 59.6 and 4.89 MPa, 12.45% and 16.43% higher than those of the reference mixture. The larger gain in tensile strength is consistent with nanosilica densifying the binder matrix and the fibers bridging cracks and redistributing stress. Combining nanosilica modification with moderate AR glass fiber reinforcement is therefore an effective route to stronger GGBS-based geopolymer concrete, and microstructural and durability studies are recommended to confirm the proposed mechanisms.

Graphical Abstract

Enhancing The Mechanical Properties of Eco-Friendly GGBS-Based Geopolymer Concrete Through Combined Effects of Fibers and Nanosilica

Highlights

·         Nanosilica and AR glass fibers combined in ambient-cured GGBS geopolymer concrete

·         Sixteen mixtures with 1–3% nanosilica and 0.4–0.8% AR glass fibers were tested

·         Strength showed an optimum, declining beyond 2% nanosilica and 0.6% fibers

·         2% NS + 0.6% fibers raised 28-day compressive strength by 12.45% over the reference

·         Splitting tensile strength gains (~16%) exceeded compressive strength gains

Keywords
Alkali-resistant glass fiber
geopolymer concrete
ground granulated blast furnace slag
mechanical properties
Nanosilica
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  • Receive Date 06 March 2026
  • Revise Date 01 May 2026
  • Accept Date 18 June 2026