Ceramics-Silikáty 57 (4) 319-327 (2013)

INVESTIGATING THE EFFECTS OF OIL PALM ASH IN METAKAOLIN BASED GEOPOLYMER

This research reports on the microstructure, compressive strength, drying shrinkage and sulfate expansion of metakaolin (MK) based geopolymers produced by partially replacing MK by oil palm ash (OPA) in proportions of 0 %, 5 %, 10 % and 15 % by weight. The specimens were cured at a temperature of 80°C for 1, 2 and 4 hours, and compressive strength test were conducted at ambient temperature at 2, 6, 24 hours, 7 and 28 day. The testing results revealed that the geopolymer with 5 % OPA gave the highest compressive strength. Scanning electron microscopy (SEM) indicated that the 5 % OPA sample had a dense-compact matrix and less unreacted raw materials which contributed to the higher compressive strength. In the X-ray diffraction (XRD) patterns, the change of the crystalline phase for higher strength was easily detectable compared lower strength.

Keywords: Compressive strength, Geopolymer, Oil palm ash, Drying shrinkage, Expansion