Characterization of palm oil fuel ash and eggshell powder as partial cement replacement in concrete

Abstract

The utilization of palm oil fuel ash (POFA) and eggshell powder (ESP) in concrete as a cement replacement is possible as green concrete materials. However, the POFA has original cellulose and physical modification is needed. This paper presents the characterization of POFA; unground POFA (UPOFA) and ground POFA(GPOFA) and ESP under microstructure examination includes x-ray fluorescence (XRF), scanning electron microscopy (SEM), and particle size analyzer (PSA). Then, the POFA-ESP as a cement replacement in concrete was investigated. Optimum mix proportion of POFA-ESP concrete was determined from compression test and GPOFA-ESP and UPOFA-ESP were through further investigation on pozzolanic reaction under x-ray diffraction (XRD) test at 14 days-concrete age. It was found that the combination of GPOFA-ESP as a cement replacement produced a concrete enhanced the compressive strength than normal concrete. ESP in this study seems like a catalyst which acting as mild accelerator or booster to improve the early age of strength development without disturb the later strength development of concrete. In addition, combination of GPOFA-ESP could increase the C-S-H gel at early age of concrete. It can be concluded that the combination of GPOFA-ESP had dual function; ESP and GPOFA took at early and later strength development, respectively.