Mechanical and microstructure characteristics of alkali-activated coal ash with α-phase ultrafine Al2O3 nanoparticles and basalt fibres

Abstract

The present study aims to enhance the mechanical, microstructural, and fracture performance of alkali-activated coal ash with different proportions of α-phase ultrafine Al2O3 nanoparticles. The inspected proportions of α-phase ultrafine Al2O3 nanoparticles are 0–3% by weight and the proportion of basalt fibres (BF) added to alkali-activated coal ash is 2% by weight of the paste. Several tests are carried out on the cubical and rectangular alkali-activated coal ash nanocomposites representative models of geopolymer to inspect their mechanical and fracture performance. Furthermore, the microstructural evaluation of tested representative pieces is carried out by making use of scanning electron microscopy. The experimental measurements portrayed the combination of 2% BF with 2% α-phase ultrafine Al2O3 nanoparticles manufactures the optimal outcomes for the mechanical and microstructural performance of alkali-activated coal ash nanocomposites. The compression strength obtained at 2% nano alumina was 26.45% larger than the regulator GC paste. The bending strength depicted the optimal outcomes at a 2% proportion of nano alumina being 118.77% larger outcomes than the regulator representative piece. The maximum elastic modulus and bending modulus at 2% nano alumina were 11.3% and 19% larger than the regulator GC paste.

Keywords

• Geopolymer
• basalt fibres
• nano alumina
• bending strength
• stress–strain curve
• SEM