Reliability of rice husk ash as substitution of portland composite cement producing green concrete

Abstract: Production of cement contributes significantly to air pollution. Previous research has shown that rice husk ash can partially replace ordinary Portland cement in the concrete mixture. This ordinary cement inIndonesia has rarely been used and replaced with Portland composite cement. Based on this phenomenon, it is necessary to know whether rice husk ash is also appropriate as a substitute for Portland composite cement. This study investigates the properties of rice husk ash by using x-ray fluorescence spectrometer and scanning electron microscope. Furthermore, the properties of cement paste were obtained by Vicat testing at replacement levels of 0, 2.5, 5, 7.5 and 10 %, respectively by weight of cement. This research was conducted in the laboratory experiments. Different from other reports, curing of specimens were not performed for up to 28 days. Treatment was performed only at room temperature without immersion, as occurs in foundation work. The result of this research showed that the higher the RHA content was in the cement paste, the higher the percentage of normal consistency. Although the setting time of cement pastes using rice husk ash was longer, it was still suitable for the requirements outlined in Indonesian standard regulations. This study provides an opportunity to use the abundant ash of rice husk ash as a substitute for composite cement in creating environmentally friendly concrete known as green concrete