Field and laboratory performance of a cold-region sand stabilized with geofiber and synthetic fluid

This paper presents results from a case study on the improvement of a poorly graded sand through treatment with geofiber and synthetic fluid. The soil improvement technology was applied in the field at a site near Barrow, Alaska. The treatment at dosages of 0.25% geofiber and 1% synthetic fluid was effective and met design requirements based on tests conducted shortly after the completion of the stabilization process. However, after going through a full freeze-thaw cycle, some deterioration in load bearing characteristics was encountered. Field CBR and soil stiffness tests were performed to quantify the strength loss in the soil. Additionally, an extensive and systematic laboratory testing program was implemented to investigate and evaluate the treatment dosages of the additives used. The laboratory tests evaluated each of the additives independently, as well as for their combined use. The best performance in the laboratory was obtained from samples containing 0.35% geofiber and 2% synthetic fluid. Freeze-thaw tests were performed on various compositions of treatment to study the potential factors responsible for the loss of strength encountered in the field. When subjected to freeze-thaw, samples experienced significant decrease in CBR performance. Also, a group of tests on cured samples were conducted to evaluate the time-dependency of soil treatment. The field dosage rates did not show any improvement with curing, however other treatment compositions indicated slight to moderate increase in CBR performance due to curing.