Mechanical and fracture behaviour of micro steel fibre-reinforced fly ash-based geopolymer paste containing nano CaCO3

The present study has investigated the mechanical properties of micro steel fibre-reinforced fly ash-based geopolymer pastes by adding different contents of nano CaCO3. Three contents (0%, 1%, 2%, and 3% by weight of fly ash) were evaluated for nano CaCO3 while the content of micro steel fibres was kept constant at 0.5% by weight of paste. A control mix containing 0.5% micro steel fibres without any content of nano CaCO3 was fabricated for comparison purposes. The evaluated mechanical characteristics of micro steel fibre-reinforced geopolymer pastes were the compressive strength, flexural strength, elastic modulus, Charpy impact strength, hardness, fracture toughness, toughness modulus, bending stress–strain response, bending load-deflection behaviour, compressive stress–strain response and toughness indices. The outcomes of the present study showed that the utilization of 2% nano CaCO3 in micro steel fibre-reinforced GPC introduced the optimum mechanical performance for compressive strength, flexural strength, fracture toughness, elastic modulus, toughness modulus, and hardness. .