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The Scientific World Journal
Volume 2013, Article ID 857586, 9 pages
http://dx.doi.org/10.1155/2013/857586
Research Article

Performance Evaluation and Microstructure Characterization of Metakaolin-Based Geopolymer Containing Oil Palm Ash

1Department of Civil Engineering, Prince of Songkla University, Songkhla 90112, Thailand
2Department of Mining and Materials Engineering, Prince of Songkla University, Songkhla 90112, Thailand

Received 12 August 2013; Accepted 16 September 2013

Academic Editors: V. Amigó and F. Pacheco Torgal

Copyright © 2013 Abideng Hawa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study reports on the microstructure, compressive strength, and drying shrinkage of metakaolin (MK) based geopolymers produced by partially replacing MK by oil palm ash (OPA). The OPA was used as raw material producing different molar ratios of SiO2/Al2O3 and CaO/SiO2. The geopolymer samples were cured at 80°C for 1, 2, or 4 hours and kept at ambient temperature until testing. The compressive strength was measured after 2, 6, and 24 hours and 7 and 28 days. The testing results revealed that the geopolymer with 5% OPA (SiO2 : Al2O3 = 2.88 : 1) 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 after heat curing for 4 hours was easily detectable compared to the samples subjected to a shorter period of heat curing.