In cold regions, saline soils can cause dissolution, settlement, and salt expansion of the roadbed under the influence of freeze-thaw cycles, so they need to be stabilized during road construction. In this study, lime, fly ash (FA), and polyacrylamide (PAM) were used to stabilize sulfate saline soils, and the stabilized saline soils were subjected to the unconfined compressive strength test (UCS), splitting test, and freeze-thaw cycle tests (FTs). The stabilization mechanism of the three materials on saline soils was also studied via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS). The test results showed that the addition of lime, FA, and PAM to saline soils can improve the mechanical properties and frost resistance of saline soils. After 28 d of curing, the UCS of FA-, PAM-, and lime-stabilized saline soils increased by at least 55%, 23%, and 1068%, respectively, and the splitting strength increased by at least 161%, 75%, and 2720%, respectively. After five freeze-thaw cycles, the residual strength ratios (BDRs) of the UCS of L2 (lime 8%), F2 (FA 11%), and P2 (PAM 1%) stabilized soils and saline soils were 71.78%, 56.42%, 39.05%, and 17.95%, respectively, and the decreasing trend tended to be stable. The saline soils stabilized by lime and FA were chemically stabilized, and their mechanical properties and frost resistance were better than the physical stabilization of PAM.

The use of natural fibres has proven successful in improving the mechanical properties of earthen construction. It is a low-cost and environmentally friendly alternative to using chemical stabilisers, such as Portland Cement. This paper presents an experimental investigation into the influence of jute fibre reinforcement on the compressive and tensile splitting strength of Jute Reinforced Compressed Earth Composites (JRCECs). The investigation considered three fibre lengths (10 mm, 20 mm and 30 mm) and three fibre dosages (0.125%, 0.25% and 0.50%) by weight. When compared to an unreinforced control mix, it was found that the incorporation of jute fibre increased the mechanical properties of the JRCEC, with the optimum mix providing an increase in compressive and tensile splitting strength of 100% and 85% respectively. Within the investigation, Computed Tomography (CT) scans were performed on the JRCEC samples to evaluate the influence of mixing methodology on the fibre distribution and orientation. Findings from this study showed that jute fibre reinforcement may be used to increase the mechanical properties of compressed earth composites, and highlights the importance of mixing methodology during the manufacturing process.