Soil stabilization

About: Soil stabilization is a research topic. Over the lifetime, 3161 publications have been published within this topic receiving 48437 citations.

Evaluating the performance of very weak subgrade soils treated/stabilized with cementitious materials for sustainable pavements

Abstract: This paper presents the results of laboratory tests that were conducted to determine the proper treatment/stabilization recipe of very weak subgrade soils at high moisture contents, and to evaluate the corresponding performance-related properties [eg, the resilient modulus and permanent deformation] for use in the design of sustainable pavement structures Four different subgrade soil types of different plasticity indices were considered in this study Three different moisture contents were selected at the wet-side of optimum that correspond to a raw soil strength value of 172 kPa (25 psi) or less All the soils were treated with different combinations of class C fly ash (or Portland cement type I) and hydrated lime to achieve a 7-day target strength values of 345 kPa (50 psi) to create a working platform and 690 kPa (100 psi) to stabilize the subgrade for subbase application Repeated load triaxial (RLT) tests were performed on laboratory molded specimens to evaluate their resilient modulus and permanent deformation behavior under cyclic loading The AASHTO T-307 procedure was followed in this study to conduct the resilient modulus tests A good correlation was observed between the water/additive ratio and the resilient modulus/permanent deformation, such that the soil specimens prepared at low water/additive ratio showed better performance than those prepared at high water/additive ratio The results of laboratory tests showed that the use of direct correlation between unconfined compressive strength (UCS) and resilient modulus for cementitiously treated/stabilized soils can be misleading

Stabilization of Soft Clay Subgrades in Virginia: Phase I Laboratory Study

Abstract: Many pavement subgrades in Virginia consist of wet, highly plastic clay or other troublesome soils. Such soils can be treated with traditional lime and cement stabilization methods. Alternatives, including lignosulfonates and polymers, are available, but their performance record is mixed and solid engineering data are lacking, which prevents reliable design. The goal of this research was to screen a suite of traditional and non-traditional stabilizers against three Virginia soils that have caused problems during construction or resulted in poor performance in service. The selected stabilizers were: quicklime, hydrated lime, pelletized lime, cement, lignosulfonate, synthetic polymer, magnesium chloride, and a proprietary cementitious stabilizer. A laboratory procedure was developed and applied to three Virginia soils obtained from Northern Virginia, Staunton, and Lynchburg. Key findings from the research include: (1) traditional lime and cement stabilizers were far more effective than liquid stabilizers (lignosulfonate, synthetic polymer, and magnesium chloride) in increasing strength; (2) the liquid stabilizers were ineffective on soils with a high moisture content; (3) the proprietary cementitious stabilizer was more effective in increasing strength than lime for all cases tested but was not as effective as the cement stabilizer; (4) quicklime and hydrated lime increased the workability of the soils although they did not produce strengths comparable to cement; (5) the strength of soils stabilized with cement and the proprietary cementitious stabilizer can be estimated based on the water-amendment ratio of the mixture; and (6) the strength of soils stabilized with lime can be estimated based on a combination of the plasticity index and the water-amendment ratio of the mixture. The benefits of subgrade stabilization are that it improves the strength, stiffness, and durability of soft subgrade soils. Such improvement allows a reduction in the required thickness of overlying pavement courses and/or an increase in pavement life. Quantifying the life cycle cost benefits requires performing pavement design studies based on anticipated traffic levels, desired serviceability, etc. The preferred design method would be a mechanistic design, which requires resilient modulus values for the stabilized subgrade and other pavement layers. Neither resilient modulus testing nor pavement design studies were included in the scope of the work for this project, but they should be included in subsequent phases.

Durability of Enzyme Stabilized Expansive Soil in Road Pavements Subjected to Moisture Degradation

Abstract: Expansive soils are problematic and susceptible to ground movements, causing significant damage to overlying structures and reduction of bearing capacity Geotechnical engineering has long recognized that the moisture variation triggers the expansive nature of soils resulting in its swell and shrinkage Numerous stabilizing additives have been used to treat expansive soils such as lime, cement and fly ash However, the use of bio-enzymes as a soil stabilizing agent is not currently fully understood This study examines the durability performance of the enzymatic stabilization of expansive soils in road pavements subjected to moisture fluctuation Number of experiments was performed under controlled conditions to investigate the mechanical and hydraulic response of stabilized soils subjected to cyclic moisture degradation at various initial moisture contents covering practical moisture ranges in applicable with road pavements Results showed that strength of stabilized soils was considerably increased with the addition of enzyme based stabilizer, revealing its ability to maintain the material stiffness over moisture fluctuation While wetting and drying tests had damaging effects on the UCS, enzyme based stabilization served to preserve soil strength effectively throughout the loading cycles Results obtained from the mechanical/hydraulics tests were further elaborated using imaging analysis which provides an insight into the mechanism of enzyme based stabilization and the influence of moisture when using this novel stabilization approach This research will substantially benefit geotechnical applications including cost-effective and sustainable road constructions

Stabilization of Clay with Inorganic By-Products

Abstract: New binder alternatives based on industrial by-products were studied for stabilization of clayey soils. The main emphasis was on pulverized, granulated blast-furnace slag activated in different ways, and on binder combinations based on fly ash and waste from desulfuration units. Cement was used as the control binder. The aim of this study was to evaluate the stabilization characteristics of new binder alternatives with different mixture combinations and to understand the effects of geotechnical index properties of clay and chemical/mineralogical composition on stabilization characteristics. The results of the laboratory tests indicate that the strength of stabilized clay is strongly dependent on the water-binder ratio, and that the strengthening effect is minimal at water-binder ratios below a certain threshold value. For the clay types examined in this study, blast-furnace slag activated with cement generally gives higher strengths than cement alone after the relatively long hardening periods usually emp...