Evaluation of eggshell lime as green accelerator on palm oil fuel ash concrete production: Effect of thermal treatment

This paper presents the potential use of eggshell powder (ESP) as green accelerator in ground palm oil fuel ash (GPOFA) concrete. Three categories of ESPs namely uncarbonised ESP (UC-ESP), carbonised ESP (C-ESP) and decarbonised ESP (DC-ESP) corresponding to no calcination and calcination at temperatures of 750 and 1000 degrees C, respectively, were prepared and studied. In addition, ESPs was used as cement replacement (0, 5, 10, 15, and 20 wt%) in GPOFA concrete and their performance were examined in term of reactivity, workability, heat hydration, compressive strength and microstructure performance. It was found that the presence of UC-ESP, C-ESP and DC-ESP can provide a low, medium and superior accelerator behaviour in the early age of GPOFA concrete. Overall, the GPOFA concrete combined with DC-ESP revealed an excellence SiO2-CaO reactivity, giving a twice compressive strength at early age and provides inductive hydration behaviour with low hydration temperature and significant improvement in dense gels formulation. Hence, this study provides a positive impact for rapid construction technology. As a conclusion, modified ESP is a highly potential as partial cement replacement and accelerator for concrete.