In this study, calcined kaolin–white Portland cement geopolymerwas investigated for use as biomaterial. Sodium
hydroxide and sodium silicate were used as activators. In vitro test was performed with simulated body fluid
(SBF) for bioactivity characterization. The formation of hydroxyapatite bio-layer on the 28-day soaked samples
surface was tested using SEM, EDS and XRD analyses. The results showed that the morphology of hydroxyapatite
was affected by the source material composition, alkali concentration and curing temperature. The calcined
kaolin–white Portland cement geopolymer with relatively high compressive strength could be fabricated for
use as biomaterial. The mix with 50% white Portland cement and 50% calcined kaolin had 28-day compressive
strength of 59.0 MPa and the hydroxyapatite bio-layer on the 28-day soaked sample surface was clearly evident.