University of Wisconsin–Madison

Grants

Production of high pH leachate from Recycled Concrete Aggregate

Professors Ginder-Vogel and Edil were awarded a grant from the Ready Mix Concrete Research and Education Foundation and the Portland Cement Association to study the production of high pH leachate from recycled concrete aggregate (RCA).

Concrete recycling reduces the need for mining of virgin aggregate, thereby conserving scarce natural resources and often dramatically decreasing transport costs and impacts. Additionally, recycling concrete reduces the need for landfill space, stockpiles and waste concrete, and illegal concrete dumping. During the recycling process, crushing or fracturing of concrete may expose fresh surface area. Due to the solubility of hydroxide-bearing minerals and other chemical reactions, the pH of water that interacts with recycled concrete may become elevated. Here, we propose to couple laboratory leaching studies, utilizing representative saturation and geochemical conditions, with results from a forensic examination of an RCA base course located at the MNROAD test facility to determine mechanisms that may limit the production of high pH of leachate.