Description
Geopolymer concrete is a durable and environment friendly construction material. However, less ductility and high brittleness are the major challenges of the geopolymer concrete. The addition of fibres in concrete impedes the fracture propagation and improves the overall mechanical properties of the concrete. This study investigates the fresh and the hardened properties of ambient cured plain and glass fibre reinforced slag-fly ash based geopolymer concrete (SFGC). All the mixes were prepared using an alkaline activator, composed of 14 molar sodium hydroxide (NaOH) solution, and liquid sodium silicate (Na2SiO3) with a modulus (SiO2/Na2O) ratio of 2. Alkali resistant glass fibres at the dosage of 1.5% by volume of the concrete were added to the mix to evaluate the workability, density, compressive and flexural strengths of glass fibre reinforced slag-fly ash based geopolymer concrete (GF-SFGC). The experimental results indicated that the addition of glass fibres in SFGC mix reduced workability but improved the density of concrete. The average compressive strength of SFGC determined at 7, 28 and 56 days was decreased by approximately 2-4% by adding the glass fibres in the mix. However, the average 28-day flexural strength of GF-SFGC was about 24% higher than the plain SFGC mix. Overall, the fresh mix of GF-SFGC was cohesive and the hardened specimens remained intact even after the failure.
