Stabilization of clayey soil using lignosulfonate

Many customary soil additives (e.g., cement, lime, fly ash and gypsum) are generally used to improve the mechanical properties of the soils. The applicability of most of these traditional stabilizers of soil is limited to particular soils. Moreover, traditionally stabilized soils in some cases exhibit high brittle behavior, which is oftentimes inappropriate for projects such as airport runways and embankments of railroads. This article presents the results of a research study in which an alternative stabilizer-Lignosulfonate (LS)-is investigated. Several basic properties of high plasticity clay, such as Atterberg limits, proctor compaction, unconfined compressive strength (UCS), effect of cyclic wetting/drying on the strength properties, stress-strain behavior and secant modulus of elasticity (E50) are assessed. To clarify the strength development due to the LS-treatment, scanning electron microscopy is performed on LS-treated and untreated clay. The LS contents were 0.5, 0.75, 1, 2, 3 and 4% by weight of the dry soil and specimens were cured for 0, 4, 7, 14, and 28 days. Results show that the LS-treatment leads to a considerable reduction in plasticity index (PI) of the soil. Also, stabilization with LS has slightly increased the optimum water content and slightly decreased the maximum dry unit weight of the soil. This stabilization has increased the stiffness and UCS of the soil without leading to a considerable brittle behavior. The increase in strength properties is ascribed to the electrostatic reaction that occurs between the mixture of LS-water and soil particles. (C) 2017 Elsevier Ltd. All rights reserved.