Using cellulose nanocrystals to improve the mechanical properties of fly ash-based geopolymer construction materials

Abstract

Ordinary Portland cement production is one of the biggest emitters of carbon dioxide. Consequently, there is a strong need for construction materials with lower environmental footprints. However, the development of alternative green construction materials requires a standardized framework. Although cellulose nanocrystals have shown considerable reinforcement potential in conventional construction materials, its effect on the mechanical properties of fly ash-based geopolymers as green construction materials is not known. Consequently, a detailed database outlining the cellulose nanocrystals interactions on the compressive strength, density, and corrosion resistance properties of geopolymers can optimize and guide further research efforts. The aims of this study were to firstly determine the effect of cellulose nanocrystals on the mechanical properties of fly ash-based geopolymers. Secondly, to produce a database of the effects of cellulose nanocrystals concentration and activator concentration on the mechanical properties of the formed geopolymers. Finally, to formulate an empirical framework to develop green construction materials. An empirical framework was developed alongside the cellulose nanocrystals-reinforced geopolymers, which were optimized using a statistical experimental design. The experimental results yielded the geopolymer property database. It was found that low cellulose nanocrystals concentrations (less than 0.5%) favoured the geopolymer mechanical properties. Using industrial wastes to produce green construction materials can divert industrial wastes from landfills and minimize the widespread use of environmentally degrading conventional construction materials. The framework developed in this study can facilitate the commercialization of green construction materials in industry.