Phosphogypsum is a solid by-product material resulting from the production of phosphoric acid, a major constituent of many fertilizers. It has been estimated that more than 800 million tons of phosphogypsum are stockpiled in the U.S. The current production rate exceeds 60 million tonnes per year, with less than 2 percent being recycled at the present time. The results of the laboratory phase of a research program to develop phosphogypsum as a road base material are presented. The research program included physical and chemical characterization of the phosphogypsum, mineralogical analysis, moisture-density relations, unconfined compressive strength testing, freeze-thawand wet-dry durability tests, and expansion testing. A comparison is made between the engineering properties of phosphogypsum and the Louisiana Department of Transportation and Development requirements for road base materials
Samenvatting