Assessing and Using the Segregation Potential in Pavement Engineering

Abstract

During winter, frost penetrates in pavement materials and subgrade soils. When the frost front reaches frost susceptible subgrade soils, water is sucked toward the frozen fringe where ice lenses are formed. Heave of the pavement surface resulting from these phenomena can reach and even exceed 150 mm for climatic conditions prevailing in Canada. Frost heave in soils is the result of the combined action of heat and moisture transfer in freezing soils. Freezing soils in a pavement system are subjected to a thermal gradient. As a result, a negative pore water pressure gradient is created behind the freezing front, in a thin layer of partly-frozen soil known as the frozen fringe. Based on this understanding of the frozen fringe conditions, Konrad and Morgernstern (1980) have developed the segregation potential concept to model one dimensional frost heave in soils. The segregation potential is a mechanistic index allowing for the quantification of the frost susceptibility of a given soil in specific climatic conditions. The segregation potential concept has been used for more than two decades for several engineering applications. The paper will describe how the segregation potential can be assessed using a freezing test or estimated using various approaches. It will also describe how the segregation potential can be used to perform frost analysis of pavements subjected to cold climates.