Experimental study of the microstructural and mechanical properties of geopolymer paste with nano material (Al2O3)

Abstract

This article presents the effect of incorporating nano-Al2O3 particles into fly ash-based geopolymer pastes. Nano-Al2O3 particles were added to fly ash at dosages of 1%, 2%, and 3% by weight, and test samples of the same paste with no nano-Al2O3 were also created. All mixtures had a constant liquid-to-binder ratio of 0.75 and were cured at ambient room temperature. Results showed that the optimum content of nano-Al2O3 particles for improving the mechanical properties of geopolymer paste was 2 wt%. The incorporation of nano-Al2O3 particles improved flexural strength, flexural modulus, fracture toughness, compressive strength, impact strength and hardness of fly ash based geopolymer paste. SEM micrographs illustrate the widespread distribution of geopolymer paste containing nano-Al2O3 particles with a more packed structure and fewer pores, resulting in greater strength in the specimens.