Publications scientifiques
Autres affiliations : Leibniz University Hannover
Claus H. Rüscher
Ceramic engineering and science proceedings
This chapter discusses how sodium waterglass (NWG) such as commercial NWG (S1), NWG from pure rice husk ash (S2) and NWG from raw rice husk ash (S3) were used for producing geopolymer cements from metakaolin (MK) as aluminosilicate source. Commercial sodium silicates are produced from combination in varied proportions of pure quartz sand and sodium carbonate treated at approximately 1400 °C obtaining the solid sodium silicate as an amorphous material. Three sodium waterglass were prepared in an experiment with the molar ratios SiO2/Na2O and H2O/Na2O kept constant at 1.5 and 12 respectively. In order to maintain these ratios, the appropriate mass of NaOH pellets was dissolved in distilled water and then mixed with commercial sodium waterglass to obtain S1, S2 and S3 were obtained by adding NaOH pellets with powder of PRHA and RHA, respectively. The chemical compositions of kaolin (Dibo), raw rice husk ash (RHA) and pure rice husk ash (PRHA) were determined by X-ray fluorescence (XRF) using PANalytical Axios mAX. TGA of crushed geopolymer cements were performed using alumina crucible between 25-1000 °C. The resulting X-ray patterns indicate that the binder could be the same in the three cases and different only on the amount of unreacted metakaolin. These results confirm the results of water absorption which indicates that Geo3 absorbed more water in their structure and leading to the lower compressive strength.
