ENGINEERED WATER REPELLENCY FOR FROST HEAVE MITIGATION: DECOUPLING THE RELATIVE INFLUENCE OF MATRIC AND OSMOTIC SUCTION

Seasonal cold weather and frost action has a major effect on the design, construction, performance, and maintenance of roadways. Frost heaving and thaw weakening are especially problematic, subjecting all elements of a pavement system to significant changes in moisture content, stress, and strain. Nationally, this leads to recurrent annual maintenance costs estimated at over 2 billion dollars, as well as additional economic impacts because of related vehicle damage, road closures, and weight restrictions. Studies identify three basic requirements for frost action; freezing temperatures, availability of water, and frost-susceptible soils. While advances have been made in designing for freezing temperatures and providing for groundwater separation, very little progress has been made in terms of in situ soil improvement. A cost and labor-intensive approach is to replace unsuitable soils. As an alternative, Engineered Water Repellency (EWR), a process in which soils are made hydrophobic is presented as a suitable barrier limiting the transport of water through these soils, resulting in frost heave mitigation. This is achieved by combining soils with cost-effective and environmentally compatible polymers and other complex organic molecules. This process explored through a multi-year project funded by the U.S. National Science foundation, involved laboratory, field, and numerical studies.