Freeze-thaw performance of pavement foundation materials

Freezing and thawing processes damage pavement foundation systems; increase pavement and vehicle maintenance costs; reduce traveler comfort and safety; decrease fuel economy; and decrease pavement life spans. Current pavement design methods provide limited guidance for characterizing frost-susceptible materials. A laboratory frost-heave and thaw-weakening test could be used to differentiate frost-susceptible materials from non-frost-susceptible materials to reduce the effects of frost action. The goal of this research was to provide guidance for selecting pavement foundation materials based on their freeze-thaw durability. The objectives of this study were to use ASTM D5918 Standard Test Methods for Frost Heave and Thaw Weakening Susceptibility of Soils to determine the relative frost-susceptibility of various soil types; study the effects of stabilizers on reducing frost-susceptibility; and determine seasonal changes of in situ pavement support conditions. The important outcomes of this research are that it is difficult to predict frost-heave susceptibility from USCS classifications; the coefficients of variation for ASTM D5918 test results were similar to published results; when stabilizing loess with cement, increased cement content decreased the range of initial moisture contents that result in maximum compressive strength; and compared to unstabilized loess, cement-stabilized loess was found to be non-frost-susceptible, but fly ash-stabilized loess showed only slight improvement. This research suggests that using a test such as ASTM D5918 to compare the relative frost-susceptibility of pavement foundation materials in the design phase may reduce the effects of frost action