Karolina R, Sofran MA, Handana M, Syahrizal, Siregar RI. Geopolymer Concrete Made From Volcanic Ash of Mount Sinabung. IJIE [Internet]. 2020 Feb. 17 [cited 2026 Apr. 8];12(1):315-20. Available from: https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/5732