D. R. A. Triman Rakasiwi and Ismail M.H., “A Review: The Performance of Reinforced Concrete Beam Containing Palm Oil Fuel Ash and Metakaolin Subjected to Four-Point Bending Test”., rtcebe, vol. 2, no. 1, pp. 181–189, May 2021, Accessed: Jul. 23, 2026. [Online]. Available: https://publisher.uthm.edu.my/periodicals/index.php/rtcebe/article/view/1354