Unconfined compressive strength and post-freeze-thaw behavior of fine-grained soils treated with geofiber and synthetic fluid

This study focuses on a relatively new non-traditional stabilizer (synthetic fluid) used in conjunction with geofiber to improve the strength characteristics of a low-plasticity fine-grained soil. The investigation is based on unconfined compressive strength (UCS) tests. An efficient geofiber dosage was determined for the soil; treating it with geofiber only for the dosage rates varying from 0.2% to 1% by weight of dry soil. The individual contribution of the geofiber and synthetic fluid to the UCS gain was studied through testing each additive independently with the soil. Additionally, UCS tests were conducted on soil samples treated with geofiber and synthetic fluid together. All experiments were conducted for both unsoaked and soaked sample conditions. Strength developments were also investigated under freezing and thawing conditions. The treatment results are discussed in detail in terms of UCS and stress-strain response of the UCS test. The results demonstrate that the use of geofiber with synthetic fluid provided the highest UCS improvement (170% relative gain) in unsoaked samples when compared with the other treatment configurations. On the other hand, the synthetic fluid, when used alone, caused a relative decrease of 21% in the UCS of untreated soil in soaked conditions. The use of geofiber with synthetic fluid performed better in terms of the UCS under freezing and thawing conditions, while the synthetic fluid alone under the same conditions performed inadequately. The stress-strain responses of the soil treated with geofiber and synthetic fluid in terms of post-peak strength, strain hardening, and ductility were better than that of treated with synthetic fluid alone. Finally, the resilient modulus for the various treatment configurations was estimated from the UCS results. The findings indicate that the investigated soil stabilization technology appears to be promising for sites that can be represented by unsoaked conditions (i.e., where adequate drainage and unsaturated conditions can be ensured). (C) 2010 Elsevier B.V. All rights reserved.