Zainuddin AN, Mukri M, Norbaya Sidek. Investigation on Soil Strength and Microstructure of Palm Oil Boiler Ash with Sodium Hydroxide and Sodium Silicate as Alkaline Solution. ijscet. 2022;13(1):57-67. Accessed May 7, 2024. https://publisher.uthm.edu.my/ojs/index.php/IJSCET/article/view/8254