Thermal behaviour, microstructural changes and mechanical properties of alkali-activated volcanic scoria-fired waste clay brick blends

Abstract

The present work aims at producing volcanic scoria (Zg) based geopolymer containing high volume of waste fired clay brick (WB). The objective was producing Zg-based geopolymer incorporating WB powders up to 50 wt% and then investigated a potential thermal stability. All formulated samples were prepared with sodium silicate made from rice husk ash and 6 M of an aqueous NaOH solution. The first series of consolidated geopolymer samples were cured at 25 °C, while the second ones were exposed to high temperatures of 400, 600 and 800 °C. The specimens were subjected to mechanical performance, physicochemical and microstructural properties evaluation. The results indicated that incorporating the WB positively influenced the physicochemical performances of geopolymers. Sample prepared with 10 wt% of WB gave highest mechanical property (33 MPa) at 600 °C. The use of WB favoured the densification and strength development of end products in the range of 25–600 °C.

Keywords

• Volcanic scoria
• Waste clay fired brick
• NaOH
• Rice husk ash
• Geopolymer
• Thermal behaviour