Effect of freeze-thaw cycles on unconfined compressive strength of fine-grained soil treated with jute fiber, steel fiber and lime

This paper presents an attempt about the effect of freeze-thaw cycles on unconfined compressive strength (UCS) of fine grained soil (low-plasticity silt) treated with jute fiber, steel fiber and lime. The stress-strain behavior (post-peak strength, strain hardening, ductility, brittleness index, resilient modulus) of the stabilized soil has also been discussed due to the treatment effects. An extensive laboratory study has been carried out conducting UCS tests under the freeze-thaw cycles of 0, 1, 2 and 3. The mixture proportions of the stabilizers were 2%, 4%, 6%, 8% and 10% for lime and 0.25%, 0.50%, 0.75% and 1% for both of the jute and steel fibers. Considering the UCS performances together with cost-benefit advantages, the effective dosage rates of stabilizers were separately found as 4% for lime, 0.75% for jute fiber and 0.25% for steel fiber. The combinations including these effective rates have been further investigated on the UCS performance and stress-strain behavior under freeze-thaw cycles. The study results that the UCS value of native soil has been performed best due to the combination of effective stabilizer rates all together (i.e., 4% lime + 075% jute fiber + 0.25% steel fiber). In this effective combination, the UCS value of native soil increases from 220 kPa to 1330 kPa for non-freeze-thaw cycle, from 205 kPa to 1300 kPa for one freeze-thaw cycle, from 156 kPa to 1100 kPa for two freeze-thaw cycles and from 114 kPa to 900 kPa for three freeze-thaw cycles. The other stabilizer combinations also show good contributions to UCS of native soil. As for the stress-strain responses, the inclusions due to the jute fiber alone in terms of post-peak strength, strain hardening, and ductility are better than the ones of steel fiber and lime at all freeze-thaw cycles. The combination of effective stabilizer rates all together offers a brittleness index with good ductility as well. In regard to the performance of resilient modulus, it is exhibited well by the combination of 4% lime + 025% steel fiber. The results obtained from the study are fairly promising to employ jute fiber, steel fiber and lime against freeze-thaw resistance. (C) 2014 Elsevier B.V. All rights reserved.