Cured alkali-activated heated clay-cellulose composites: Microstructure, effect of glass addition and performances

Abstract

The co-presence of geopolymers and cellulose in clay-based materials could improve their performances. Thus, cured NaOH-activated heated clay-cellulose (up to 10 mass%) composites were prepared, and their microstructural characteristics were investigated. Moreover, the effect of waste glass addition on the composites characteristics was evaluated. The results showed that zeolite (chabazite) and sodium carbonate were formed from metakaolin and by carbonation respectively, and the zeolization process slowed down after 5 days of curing because of ions immobilization. The coating of metakaolin particles by the amorphous cellulose II-Na formed reduced drastically the formation of zeolite. The presence of cellulose II-Na resulted in the porosity decrease, and consequently the mechanical strength and density enhanced. The results also showed that the kinetics of water absorption by the composites followed the pseudo-first order equation, and the rate constant was found to be 4.3×10−3s−1. Moreover, the reinforcing effect of the cellulose fibbers was annihilated by the formation of glass derivatives.