ASCERTAINING OPTIMAL PROCESSING TEMPERATURE AND DURATION FOR COCONUT SHELL ASH AS A SUPPLEMENTARY CEMENTITIOUS MATERIAL

This current study established the optimal processing temperature and duration for the oxide composition of coconut shell ash (CSA) through a literature inquiry. Parameters such as the concentrations of (SiO₂ + Al₂O₃ + Fe₂O₃), CaO, and SO₃ in CSA, in reference to ASTM C618-2019, classification for fly ash, were figured from existing studies. The temperature and duration in existing studies, with the highest (SiO2 + Al₂O₃ + Fe₂O₃) score and satisfying the requirements of CaO and SO₃, were recommended as the optimal processing temperature and duration for the optimization of the oxide composition of CSA. Data source included journals and conference publications not older than seven years, and clearly stated the processing temperature and/or duration. The optimal processing temperature was 700 °C for a duration of 3 hours. The corresponding (SiO₂ + Al₂O₃ + Fe₂O₃) score in mass percentage was 80.46, exceeding the minimum required of 50%. Mass percentage concentration of CaO (6.25) did not exceed 18.00% and SO₃ (0.69) did not exceed 5%. Thus, both the concentrations of CaO and SO₃ were within acceptable limits. The findings offer a practical guide to construction practitioners as to the optimal processing temperature and duration that optimize the oxide composition of CSA as supplementary cementitious material, limiting discrepancies in processing temperatures and duration characterizing previous studies.