Enhanced thermal stability in K2O-metakaolin-based geopolymer concretes by Al2O3 and SiO2 fillers addition

摘要: Based on the principle of stability geopolymer gel as refractory binder, a geopolymeric paste in K2O–Al2O3–SiO2 system was developed and used to produce concretes by adding various amount α-quartz sand (grain size range 0.1 μm 1 mm) fine powder alumina 0.1–100 μm). The consolidated samples were characterized before after sintering using optical dilatometer, DSC, XRD SEM. total shrinkage 25–900 °C less than 3%, reduced with respect most diffused potassium or sodium based systems, which generally records >5% shrinkage. maximum basic composition recorded at 1000 17% is 12% addition. temperature densification shifted from 1150 1200 75 wt% respectively. sequences could be resumed dehydration, dehydroxylation, finally plastic deformation due importance liquid phase. formulations this study appeared promising candidates for high-temperature applications: refractory, fire resistant insulating materials.