Performance of nano titania-reinforced slag/basalt geopolymer composites

Abstract

In Egypt, basalt manufacturing generates waste materials at a rate of about 33%. The disposal of basalt waste through the manufacturing of cementitious materials is an economically feasible approach. This work involved the fabrication of a one-part slag/basalt waste geopolymer cement (GP) enhanced by nano-TiO2. The physico-mechanical properties of the different GP mixes were investigated. The durability against fire at up to 750 °C, sulfate (SO4−2) attack, and irradiation with significant dosages of γ-rays at up to 1500 kGy were assessed. Phase composition and microstructure were explored through various techniques as XRD, TG, and SEM. The findings demonstrated that basalt incorporation up to 20% within the GP mix boosted its mechanical characteristics after 28 and 90 days of curing by 8.5 and 2.5%, respectively, while 60% replacement diminished the strength by 30%. Slag/basalt GP showed a comprehensible resistance to SO4−2 ions attack, and its strength was intensified by 14% after 4 months of immersion. Additionally, the blended GP mixes could preserve 40% of their strength after being exposed to 1500 kGy of γ-rays and about 50% of their strength after firing at 750 °C. Admixing GP by NT showed a synergic impact for diminishing setting times, boosting compressive strength by 5 ~ 15% compared to reference mix along with an improvement in the microstructure. Furthermore, distributing NT through GP greatly improved durability after firing at 500 and 700 °C and irradiating with high dosages of γ-rays. This feature is mostly connected to the catalytic capabilities and filling activities of NT in boosting geopolymerization processes.