Authors: Caitlin Graeber, Souvik Roy, Chan Lan Chun, Manik Barman, Civil Engineering Department, University of Minnesota Duluth
Abstract: The use of chloride-based salt as a deicer for winter road maintenance has been a longstanding practice throughout the state of Minnesota and the country. However, once chloride enters the water, it is not naturally broken down, transformed, or removed from the environment, resulting in accumulation in the watershed and detrimental ecological and water quality impacts in freshwater systems. In order to protect freshwater resources and to prevent this issue from worsening with time, an alternative method for providing sustainable and effective winter road maintenance is needed. In some areas of Minnesota, sand is mixed with salt as an abrasive to provide additional traction to the roads, however its effectiveness is not well established. This study will investigate the potential of a variety of organic and inorganic industrial byproducts such as corn grit, timber waste, and taconite waste rocks local to Minnesota as alternatives to conventional sand and salts. Chemical and physical properties of the materials were characterized, including material elemental composition, morphology, particle size distribution, sorption capacity, and specific gravity to establish a foundational understanding of the material. Skid resistance tests and environmental impact assessments were performed to evaluate traction effectiveness and material safety. Based on these results, design and formulation of composite mixtures is in progress and the composites will be tested for effectiveness and safety on different pavements. Current results show promise for the organic material corn to be used as a sorbent for salt brine and for the inorganic material taconite waste rock to be used as an abrasive in the composite. This work will provide a potential new material for winter road maintenance as well as a streamlined method for evaluating potential abrasives/deicers which will be valuable for expediting future studies of alternative materials.