Showing papers on "Soil stabilization published in 1989"

Desert crust formation and soil stabilization

Abstract: A microbially formed soil cover known as desert crust carpets vast regions of land in the arid climates. An accretionary phenomenon in a generally erosional setting, it stabilizes soil and enhances its quality. It is potentially applicable to reclamation of unconsolidated soil in desert regions of the world. This paper reviews the work on microbial crusts, how they develop and contribute to soil quality, and what environmental variables enhance or impede their growth. Microbiological issues relating to the identification, isolation, and culturing of important members of this microbial community are discussed. Some practical problems are considered and suggestions for further research made.

Soil Improvement Techniques and Their Evolution

Abstract: Contents: Introduction; Temporary soil improvement techniques; Permanent soil improvement without addition of any material; Permanent soil improvement by adding materials; Testing the completed soil improvements; General conclusions; References.

Properties of solid waste incinerator fly ash

Abstract: Since the late 1950s solid waste incinerators have become widely used in the United States. The incineration of solid waste produces large quantities of bottom and fly ash, which has been disposed of primarily by landfilling. However, as landfills become undesirable other disposal methods are being sought. An experimental research program is conducted to determine engineering properties of solid waste incinerator fly ash (SWIF) in order to evaluate the feasibility of using the material for compacted fill and road and subbase construction. Moisture‐density relationship, permeability, shear strength, and California bearing ratio (CBR) are investigated. The effects of densification on these engineering properties are also examined. In addition, the effectiveness of cement and lime stabilization is investigated using two common mix ratios. Test results of stabilized mixes are compared to the unstabilized material. Cement stabilization is found to be very effective in reducing permeability, and increasing shea...

Evaluation of admixture stabilization for problem laterite

Abstract: The paper presents results of research carried out to evolve suitable evaluation criteria for admixture stabilization for problem laterite where Portland cement is used as the stabilizer and hydrated lime as the admixture. The results presented show that there are promises of increased strength gain with time. In addition, high durability is recorded for the range of mixes tested. Accordingly, unconfined compressive strength (UCS) and California bearing ratio (CBR) values of 1.38N/mm2 and 90%, respectively, are recommended as evaluation criteria for this form of stabilization for problem laterite. This high value of UCS compared with the conventional value of 1.08N/mm2 for lime stabilization is justified by the superior pozzolanic nature of the cementitious reaction in this admixture stabilization.

Stabilization of expansive clay soils

Abstract: Natural hazards cause billions of dollars of damage to transportation facilities each year--only flooding causes more damage than expansive soils. Nearly all types of transportation facilities have been affected by expansive soil behavior and, as a result, many have failed or are no longer serviceable. It is imperative that the damage caused by expansive soils be controlled, and proper application of soil stabilization methods can significantly reduce the damage that results from these problem soils. The purpose of this presentation is to discuss the phenomena associated with stabilizing these soils, their behavioral patterns that affect stabilization, and the initial and remedial stabilization methods that can be applied to them. The factors considered include conditions requiring and allowing stabilization, changes of properties with time, the effects of stress history and desiccation, the influence of climate, and the effects of physicochemical environments. Effects that can be improved by stabilization are pinpointed. Stabilization methods are described that improve selected properties of expansive soils by mechanical and chemical means. Well-established methods are discussed along with those that are very promising. Examples of remedial treatments are discussed. It is concluded that there is a need for analyses of all alternatives and for stabilization during construction rather than costly remedial projects. Research needs are outlined that can improve our understanding of the stabilization requirements of these problem soils.

Property changes induced in clay soils when using lime stabilization

Abstract: Lime is being used increasingly to modify and stabilize soils for numerous engineering applications such AS Embankments, road subgrade and sub-base stabilization and foundations for small buildings. It is therefore important that engineers using this technique are aware of the nature of the changes imparted to soils by the addition of lime, and of the modifications which are brought about in the physical and mechanical properties of soils by lime treatment (soil strength, permeability, frost resistance and plasticity). This paper reviews the current state of knowledge regarding the way in which lime modifies the properties of soils, and reports on the observed changes on a Devonian red marl when mixed with lime and cured in different environments. The results of the work suggest that more effective stabilization may be achieved, even at normal ambient temperatures, by the use of further chemical additives in addition to lime. (TRRL)

Studies on time-granulated blast furnace slag as an alternative binder to cement

Abstract: This paper deals with the activation of granulated blast furnace slag (GBFS) and slag-fly ash/burn clay pozzolana mixes in presence of lime and lime with gypsum. The paper highlights the effectiveness of lime- GBFS mix with and without additives as an alternative binding material. It includes mortar studies and stabilisation of alluvial soil with lime-GBFS mixes. Investigations showed that strength development of 1:3 mortar was highest when 7.5 per cent gypsum was also added to lime-GBFS mix. The alluvial soils could be satisfactorily stabilised with both lime-GBFS and lime-GBFS with 7.5 per cent gypsum or by replacing 20 per cent of GBFS with fly ash. (A)

Detailed observations on the nature of frost heaving at a field scale

Abstract: Observations made using a system of ring magnets have provided a detailed picture of differential soil strain associated with frost heaving at a field scale. The results reveal the evolution of heave as freezing advances through the soil and the variation of soil strain with depth and time, and with soil temperature conditions. The results indicate that soil strain characteristically continues within frozen soil, sustained, it is proposed, by continuing water migration into the frozen soil. Consequently a considerable thickness of frozen soil appears to be actively involved with moisture movement and ice accumulation during frost heaving. The observations support the view that frost heave generally depends in a complex manner on the thermodynamic conditions of temperature and water and ice pressures as they are modified by the rheological properties of the soil. Key words: frost heave, differential soil strain, frost heave measurement.

Design Methodology for Foundations on Stone Columns

Abstract: Stone columns offer the geotechnical engineer a valuable and viable technique for stabilizing sites underlain by soils ranging from soft clays to loose silty sands A discussion of the design methodology prepared by the authors for the Federal Highway Administration (FHWA) is presented While emphasis concentrates on soft soil applications, use of stone columns in loose silty sands is also discussed Important considerations of structure type, design loadings, field construction and inspection aspects are presented For appropriate soil and site conditions, stone columns can significantly accelerate the time for consolidation, improve stability, dissipate pore pressures and prevent liquefaction of subsurface soils

Class c fly ash as a full or partial replacement for portland cement or lime

Abstract: A study was undertaken to evaluate the stabilization or modification of sands and clays using ASTM Class C fly ash as a full or partial replacement for hydraulic cement or hydrated lime. Strength and durability tests demonstrated that the Class C fly ashes of the study could be substituted for cement in some sands. Improvement of the sands was provided by the matrix formed with fly ash acting as a filler and as a cementing agent. The test results indicate the importance of the gradation characteristics of the materials and the effects on matrix quality due to the presence of fines in the natural sands. Also, improvements in the plastic properties and gains in soil support with the addition of fly ash and/or lime were evaluated for two clays. However, test results and analyses demonstrated that the Class C fly ash does not effectively compete as a substitute for lime in the treatment of clays.

Jet Grout Stabilization of Peaty Soils Under a Railway Embankment in Italy

Abstract: The construction of two railway embankments on a peaty soil deposit up to 7m thick required a foundation improvement program meeting very strict specifications in terms of environmental protection, speed of execution and early effectiveness. The problem was solved by a jet grouting procedure, selected and optimized after exhaustive field testing. Design features and results of laboratory tests on samples recovered after the treatment are outlined, together with a statistical interpretation intended to estimate the in situ composition of the treated soil. Finally, the instrumentation installed for the long term monitoring of strain distribution in the ground is described, and the preliminary data collected are reviewed.

Surface soil stabilization basics

Abstract: Soil stabilization can be defined by the function of the improved soils. Those functions include surface stabilization, slope stabilization, and deep stabilization. This article covers surface stabilization, which is defined as the hardening of surface soils with various binders such as lime, cement, fly ash and asphalt. Such hardening increases the load bearing strengths of soils and permits them to carry the weight of a new facility (highway, airfield, etc.). It also provides a firm work platform for the contractor during construction. Included in the article is information on the use of lime, cement, fly ash, asphalt, polymers, and geotextiles for stabilization. Construction methods are also described.

The effects of pulverization on the strength and durability of highly active clay soils stabilized with lime and portland cement - summary. proceedings, soil stabilization technology exchange workshop, 7-8 november 1989, denver, colorado

Abstract: The research reported in this paper explored the effects of the degree of pulverization of a highly active clay soil on the resulting strength and durability to wet-dry tests following stabilization with Portland cement or lime. The addition of Portland cement was found to improve compactability, which led to higher strengths for the materials treated with it. The lime modified heavy clays were found to resist shrink-swell during wet-dry tests much better than the Portland cement treated clays. The overwhelming evidence from this study supports two concepts having to do with the degree of pulverization before stabilization. The finer the pulverization in the field the better the results of soil stabilization, especially for highly active clay soils. In addition, and extremely important, the degrees of pulverization used in the laboratory to establish designs and specifications for field use should be the same as to be utilized in the field.

A study on strength of lime-stabilized clay

Abstract: In order to investigate the effectiveness of lime stabilization on the soft Ariake clay, several samples were obtained from three locations, namely Hasuike, Morodomi and Takeo. The unconfined compressive strength was used as a criterion to judge the improvement effect. The results from this study indicate that lime can be used to stabilize the soft Ariake clay. Gypsum should not be employed as additive. Salts, such as calcium chloride or sodium chloride, may be beneficial when used as additive. Pozzolanic reaction rarely occurs in lime stabilization of Ariake clay. Instead, calcium carbonate is formed which creates weak binding power. Microbes living in the clay may be the main culprit of carbonation of calcium ions from the lime.

Pulverization, use of lime/fly ash cut costs

Abstract: A 2.7-mi length of Baseline Road in Roseville, a Sacramento suburb, was potholed and rough, had substandard vertical alignment, and needed reconstruction to safely carry increasing traffic. This article describes the pulverizing of the old, deteriorated asphalt pavement and stabilizing the pulverized material and base with a dual lime/fly ash process. Soil conditions under the old pavement varied from heavy clay to sandy loam, which led to the use of both lime and fly ash as binders.

A study of strength of lime-stabilized clay

Abstract: In order to investigate the effectiveness of lime stabilization on the soft Ariake clay, several samples were obtained from three locations, namely Hasuike, Morodomi and Takeo. The unconfined compressive strength was used as a criterion to judge the improvement effect. The results from this study indicate that lime can be used to stabilize the soft Ariake clay. Gypsum should not be employed as additive. Salts, such as calcium chloride or sodium chloride, may be beneficial when used as additive. Pozzolanic reaction rarely occurs in lime stabilization of Ariake clay. Instead, calcium carbonate is formed which creates weak binding power. Microbes living in the clay may be the main culprit of carbonation of calcium ions from the lime.

Soil stabilization in Kuwait : applications, market, and cost-effectiveness

Abstract: This communication introduces the concept of soil stabilization as a general framework in which chemical stabilization of soil is emphasized. The stabilization experience in Kuwait is presented, and the state of demend for the various stabilizers is investigated. The communication concludes with an evaluation of the cost-effectiveness of different chemical stabilizers