Rice husk ash-geopolymer composite

Abstract

This research aimed to enhance properties of fly ash based geopolymer through usage of three types of rice husk ash (RHA). The replacement in the content of 0%, 3%, 5% and 10% by weight was chosen. The RHA used in this study were obtained from (i) the rice drying-process (ii), (iii) in house by burning RH at 600°C and 700 °C. Liquid sodium silicate (LSS) and sodium hydroxide (SH) solution were used as activating agents. The weight ratio of LSS to SH was 1.0 and total liquid to solid was 0.6. The geopolymer prepared without RHA (the control) gave an average compressive strength of 35.91±3.30 MPa. All types of RHA replacement at 3% resulted in an improvement of compressive strength. Further increasing RHA content resulted in an adverse effect on workability and compressive strength of the final products. The highest compressive strength value of 42.52±4.86 MPa was obtained at 3% replacement using RHA burnt at 700 °C. The density results showed a decreased when incorporation of high content of RHA was beyond 5%.