Effect of Particle Shape on the Behavior of Polymer-Improved Sandy Soil Used in Pavements Due to Freeze-Thaw Cycles

Abstract

Freeze-thaw cycles have a significant negative effect on the engineering behaviour of soil in cold regions. In this study, the compressive strength of stabilized, poorly graded sandy soil used in road pavement that was subjected to different freeze-thaw cycles was studied. Samples with three different particle shapes were stabilized with a binder developed by mixing polyvinyl acetate (PVAc) and ethylene glycol monobutyl ether (EGBE). The PVAc/EGBE weight ratio was 2:1, and PVAc was added at 1%, 2%, and 3% of the dry weight of the soil, with the effect of up to ten freeze-thaw cycles evaluated. Results showed that the addition of binder decreased optimum moisture content and increased compressive strength. An increase in particle roundness results in a decrease in the magnitude of compressive strength but increases the soil composite ductility. Changing particle shape from angular to rounded resulted in a more significant decrease in compressive strength than changing from rounded to well-rounded. The decrease in compressive strength is most significant between the first and fourth freezing-thawing cycles and marginal between the fourth and tenth. The negative effect of increasing the roundness of particles is compensated by increasing binder percentages.