Improving of base course materials characteristics using industrial wastes

Abstract

Phosphogypsum is a solid by-product waste generated from phosphoric acid industry. This paper presents the effectiveness of mixing Phosphogypsum with crushed limestone to use this blend as road base course. Seven percentages (0, 5, 10, 15, 20, 25 and 30%) of Phosphogypsum were replaced from crushed limestone mixture dry weight. The influence of blending Phosphogypsum with crushed limestone was evaluated by preparing and testing mixture with several percentages of phosphogypsum and crushed limestone to determine some of their properties as maximum dry density, optimum moisture content, un-soaked California bearing ratio, soaked California bearing ratio, swelling percent and California bearing ratio after a series of wetting-drying cycles. The results indicate that the mechanical characteristics were improved by adding phosphogypsum to the crushed limestone mixtures.