Babiker, Mohammed, & Salaheldin M. Elarabi. " The study of the variation effect in the percent of the fibers in the gradients of composite materials on the percentage of water absorption of concrete beams when using 20% from the weight of cement in concrete beams." Gezira Journal of Engineering and Applied Sciences [Online], 17.2 (2022): n. pag. Web. 25 Jun. 2026