Effects of adding nano-TiO2 on compressive strength, drying shrinkage, carbonation and microstructure of fluidized bed fly ash based geopolymer paste.

This study aims to investigate the effects of nano-TiO 2 addition on properties of fluidized bed fly ash based geopolymer. Compressive strength, drying shrinkage, carbonation and microstructure of fluidized bed fly ash based geopolymer incorporating nano-TiO 2 were reported. Geopolymer specimens were prepared by alkali activation of fluidized bed fly ash in sodium silicate and sodium hydroxide solutions and were cured in microwave radiation environment plus a heat curing period. Properties for geopolymer with and without nano-TiO 2 were assessed and compared. The experimental results reveal that the addition of TiO 2 enhances both the early and later age compressive strength of geopolymer with the increasing content of nano-TiO 2 . The strength enhancement effect of nano-TiO 2 on geopolymer is more obviously when 5% nano-TiO 2 is introduced at 28-day. Microstructure analysis uncovers that the addition of nano-TiO 2 promotes the formation of geopolymer and results in compact microstructure with less cracks. The incorporation of nano-TiO 2 particles improves the carbonation resistance and reduces the drying shrinkage of geopolymer. [ABSTRACT FROM AUTHOR]