THE PERFORMANCE OF MARGINAL GRAVEL MATERIALS USED FOR SURFACING GRAVEL ROADS: A CASE STUDY OF IRINGA REGION. The Tanzania Engineer - Journal of the Institution of Engineers Tanzania [Internet]. 2025 Oct. 14 [cited 2026 May 28];14(1):10-21. Available from: https://iet-journal.or.tz/index.php/ttejiet/article/view/1