Abstract
This study focuses on
the preparation of geopolymers using various proportions of kaolinite and
calcite mixture, and the effects of kaolinite mass ratio to calcite on
compressive strength of kaolinite/calcite-based geopolymer. Several geopolymer
samples were formed using pure kaolinite, pure calcite, and various mass ratio
of kaolinite to calcite to examine properties of the geopolymers. The impact of
NaOH concentration on the compressive strength of the geopolymers was also
examined. The results of the laboratory analyses indicate that the compressive
strength of geopolymers did not increase steadily with increasing concentration
of NaOH. The optimum workability of geopolymers was obtained at 10 M NaOH and
30 % kaolinite content in the mixture. Several sensitivity experiments were
carried out using the parameters at cure temperatures of 22, 45, 65 and 85oC.
The best compressive strength of 12.68 MPa was obtained on the 28th day of
curing process at 85oC. The structural
evolution of the geopolymers prepared was investigated using FTIR spectroscopy.
They were also characterized by X-Ray Diffraction
(XRD) and Scanning Electron Microscopy (SEM).