Enhancement of mechanical and toughness properties of carbon fiber-reinforced geopolymer pastes comprising nano calcium oxide

The high carbon footprint of cement production is dangerous to environmental sustainability, which enforces the current research to discover an alternative of cement in the concrete industry. Geopolymer (GPMR) paste incorporating nanoparticles and micro-fibers is the most suitable replacement for the cement; therefore, it is essential to study the behavior of fiber-reinforced GPMR pastes including nanoparticles. The current study aims to ameliorate the fracture, microstructural, toughness, and mechanical behavior of micro carbon-FR fly ash-based GPMR paste by utilizing different quantities of nano calcium oxide (NCO) along with the combination of micro carbon fiber (CF) (0.5 wt.%). The investigated quantities of NCO in the current study are ranged between 1 and 4%. The control mix is also fabricated for the comparison purpose having only micro-CF without NCO. The results showed that the application of NCO with a content of 3% is the most effective for improving the compressive strength, impact strength, and hardness of micro carbon-FR fly ash-based GPMR paste whereas 3% use of NCO presented the optimum results for the fracture and flexural behavior of GPMR paste. The SEM analysis presented that the CF and GPMR matrix have an effective interlocking that can be attributed to the ability of NCO to refine and give a densified matrix of the GPMR mix.