D. . M. Setiawan, “Scrap Rubber and Asphalt for Ballast Layer Improvement”, IJIE, vol. 11, no. 8, pp. 247–258, Dec. 2019, Accessed: Apr. 07, 2026. [Online]. Available: https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/5326