"Use of Polypropylene Waste Plastic Pellets As Partial Replacement for Fine Aggregate in Concrete". University of Khartoum Engineering Journal 9, no. 1 (أكتوبر 19, 2022). تاريخ الوصول يوليو 8, 2026. https://onlinejournals.uofk.edu/kuej/article/view/951.