Stabilization Of Expansive Soil Research Articles

A Review on Different Types Soil Stabilization Techniques

Soil stabilization is the process of improving the shear strength parameters of soil and thus increasing the bearing capacity of soil. It is required when the soil available for construction is not suitable to carry structural load. Soils exhibit generally undesirable engineering properties. Soil Stabilization is the alteration of soils to enhance their physical properties. Stabilization can increase the shear strength of a soil and/or control the shrink-swell properties of a soil, thus improving the load bearing capacity of a sub-grade to support pavements and foundations. Soil stabilization is used to reduce permeability and compressibility of the soil mass in earth structures and to increase its shear strength. The main objective of this paper is to review the physical and chemical properties of soil in different types of stabilization methods. Stabilization and its effect on soil indicate the reaction mechanism with additives, effect on its strength, improve and maintain soil moisture content and suggestion for construction systems. Soil stabilization can be accomplished by several methods. All these methods fall into two broad categories namely mechanical stabilization and chemical stabilization. Mechanical Stabilization is the process of improving the properties of the soil by changing its gradation and chemical stabilization of expansive soil comprises of changing the physico-synthetic around and within clay particles where by the earth obliges less water to fulfill the static imbalance and making it troublesome for water that moves into and out of the framework so as to fulfill particular designing road ventures.

Stabilization of Expansive soil using Ground Granulated Blast furnace Slag

Stabilization of Expansive soil using Ground Granulated Blast furnace Slag

Stabilization of Expansive Soil with Cement Kiln Dust and RBI Grade 81 at Subgrade Level

The present research work deals with an expansive high plastic clayey soil with cement kiln dust (CKD) and stabilizer (RBI Grade 81). The physical and engineering properties of soil are plasticity, compaction, unconfined compressive strength (UCS), consolidation and California bearing ratio (CBR) of the clayey soil and clay treated with CKD and stabilizer were determined. Soil chemistry was examined before and after treatment using scanning electron microscope (SEM) and elemental dispersive spectrometer. The clay mixed with CKD, CKD and RBI Grade 81 was found that optimum contents are 10 % (CKD), 15 % CKD with 4 % RBI Grade 81, respectively. The result indicates that CKD alone will decrease maximum dry density and increase optimum moisture content. CKD with RBI Grade 81 slightly increases maximum dry density and decreases optimum moisture content. UCS increased with CKD alone and CKD with RBI Grade 81 from 88.3 to 976 kN/m2, respectively. CBR values were increased by the addition of CKD, CKD with RBI Grade 81 from 1.65 to 21.7 %. With the curing time of 3, 14 and 28 days, UCS and CBR values were increased due to pozzolanic reaction from cementations material. The treated soil has considerable reduction in compression index. SEM images clearly indicate the formation of CSH and CAH gel.

English

English

Ground granulated blast furnace slag amended fly ash as an expansive soil stabilizer

The potential of using a binder for stabilization of expansive soils that consists of a mixture of fly ash and ground granulated blast furnace slag (GGBS) is evaluated in this study. The joint use of these two materials to form a binder provides new opportunities to enhance pozzolanic activities that may reduce the swell potential and increase the unconfined compressive strength of expansive clays. The influence of different percentages of binder on the Atterberg limits, compaction characteristics and unconfined compressive strength of an artificially-mixed soil were examined. The addition of binder was shown to bring about a significant improvement in these soil properties. It was found that the liquid limit and plasticity index of the expansive soil decreased considerably with the addition of binder, while the strength improved. Adding a small amount of lime (one percent) further improved the soil properties by enhancing the pozzolanic reactivity of the binder. Based on the results of the unconfined compressive strength tests, the addition of 20% binder is recommended as optimum content. In addition, the mineralogical and morphological studies of soil specimen stabilized with optimum binder content suggested the formation of hydrated particles and cementitious compounds as a result of the reaction between the clay and the binder. Test results indicate that the use of GGBS mixed fly ash as binder to stabilize expansive is well suited for sustainable construction besides economic benefits.

Behavior of Expansive Soil Treated with Steel Slag, Rice Husk Ash, and Lime

AbstractThis paper presents the stabilization of expansive soil (C) with steel slag (SS), rice husk ash (RHA), and quick lime (L). The geotechnical properties, shearing strength characteristics, and dynamic properties of stabilized soil have been studied. The optimum mix is found to be in the proportion of 65C+20SS+5L+10RHA. The unconfined compressive test shows that strength of treated soil increases about 45 and 90% for uncured and cured samples at 30 days. The soaked California bearing ratio (CBR) test shows that the strength increases with increasing curing periods from 7 to 30 days. Laboratory strain-controlled cyclic triaxial tests have been carried out under undrained conditions to study the dynamic properties of stabilized soil for different strain amplitudes and frequencies. The stiffness of stabilized soil increases to 58–78% as compared to clay soil. This study discussed the suitability of stabilized material for subgrade pavement.

Remediation of Expansive Soils Using Agricultural Waste Bagasse Ash

Bagasse is a fibrous material remaining after crushing sugarcane to extract its juice; and bagasse ash is produced after burning bagasse. Improper disposal of this material can create environmental problems around sugar manufacturing plants. Bagasse ash, comprising a high percentage of silica (SiO2), is considered as a sensible pozzolanic material with non-reactive behaviour and has potential to be used in road subgrade stabilisation. One of the main challenges for transportation organisations in Australia is to treat subgrades including expansive soils. Expansive soils exhibit significant movements when the moisture content changes, and hence it causes substantial damage to road pavements constructed over these type of soils. Road engineers need to employ materials having acceptable strength, relatively low price and being eco-friendly. In order to demonstrate the potential ability of bagasse ash in curtailing the adverse effects of expansive soils on roads, an array of experimental tests using bagasse ash have been conducted. In this study to activate and improve the effectiveness of bagasse ash, hydrated lime was used and mixed with black soil samples, collected from Queensland Australia. Samples were prepared using different contents of bagasse ash and hydrated lime (0%, 6%, 10%, 18% and 25% by the dry mass of soil), at a ratio of 3:1, respectively. The results of free swell ratio (FSR) test, unconfined compression strength (UCS) and California bearing ratio (CBR) tests are presented for untreated and treated samples after various curing time periods of 3, 7 and 28 days. The outcomes of these tests clearly demonstrate that stabilisation of expansive soils using bagasse ash and hydrated lime not only improves the strength, but also facilitates to cope with environmental concerns through reduction of sugar industry waste material.

Behaviour of Expansive Soils Stabilized with Hydrated Lime and Bagasse Fibres

Soil stabilization is the most common ground improvement technique adopted to improve problematic soil properties. This investigation exhibits a series of laboratory tests conducted to evaluate the influences of bagasse fibres and hydrated lime addition on the engineering properties and shrink-swell behaviour of stabilised expansive soils. Bagasse fibre is industrial waste by-product left after the crushing of sugar cane for juice extraction that was used in this study as reinforcing component for expansive soil stabilization. The expansive soils used in this investigation were collected from Queensland, Australia. In order to investigate the influences of bagasse fibres on the engineering behaviour of expansive soil, varying proportions of randomly distributed bagasse fibres of 0.5%, 1.0%, and 2.0% were added to expansive soil and hydrated lime-expansive soils mixed with different bagasse fibre proportions were also investigated. Although, an array of experimental tests have been undertaken on untreated and treated expansive soil samples, merely the outcomes of linear shrinkage, unconfined compressive strength (UCS) tests after various curing periods of 3, 7 and 28 days are presented in this paper. Other test results have been identified as follow up research. The findings of this experimental investigation indicate that bagasse fibre reinforcement blended with hydrated lime increased the compressive strength of expansive soil with increase in curing time and additives contents, whereas the linear shrinkage of stabilised expansive soils decreased with increasing hydrated lime and bagasse fibre proportions and curing periods. Based on the reasonable laboratory test results, it can be noted that the expansive soils can be successfully stabilized by combination of hydrated lime and bagasse fibres.

Lime stabilization of expansive soil from Sergipe - Brazil

Expansive soils are characterized by volumetric changes caused by variations in moisture. They can cause several damages to civil constructions, especially to lightweight structures, including cracks and fissures. Chemical stabilization through addition of lime is one of the most effective techniques used to treat this type of soil. Due to cationic exchanges, lime can significantly reduce swell potential. This research studied a disturbed sample of expansive soil collected in Nossa Senhora do Socorro – Sergipe, Brazil, through the following laboratory tests: sieve and hydrometer tests, Atterberg Limits, compaction, free swell and swell pressure. All direct and indirect methods mentioned in this paper indicated that the natural soil presented high to very high degree of expansion, which reached approximately 20% of free swell and nearly 200 kPa of swell pressure. In order to evaluate the effect of lime, the same tests were conducted in soil-lime mixtures, using lime contents of 3%, 6% and 9%. The results confirmed the efficiency of lime stabilization. It was noted that, as lime content increased, there was reduction of clay fraction and increment of silt fraction; plasticity index decreased to nearly its half; compaction curve was displaced; and free swell and swell pressure reduced significantly.

The Effect of Polypropylene Fiber in the Stabilization of Expansive Soils

The Effect of Polypropylene Fiber in the Stabilization of Expansive Soils

Swell-compressibility characteristics of lime-blended and cement-blended expansive clays – A comparative study

Chemical stabilisation of expansive soils has been quite efficacious in reducing swelling characteristics, namely, swell potential (S%) and swelling pressure (ps). When chemicals such as lime and cement are added to an expansive clay, flocculation and cementation take place. Flocculation, which is an immediate reaction, is instrumental in reducing plasticity and swell potential significantly. It also reduces the time required for equilibrium heave. This paper presents experimental data on lime-blended and cement-blended expansive clay specimens. Free swell index (FSI), heave, rate of heave and swelling pressure were studied. FSI, heave and rate of heave decreased with increasing lime content and cement content in the blends. But, during a 3-day inundation (a period, generally allowed for the sample to attain to equilibrium heave), cementitious products developed and resisted the applied compressive loads stiffly, resulting in high swelling pressures in the case of lime-blended specimens. Swelling pressure could not be determined in the case of cement-blended specimens. Hence, short inundation tests (inundating the specimens only for 15 minutes) were performed. But, even from these tests, swelling pressure could not be determined for cement-blended specimens. This indicated the development of strong cementitious products in them. It was interesting to find that, in both long and short duration, the lime- and cement-blended specimens attained to equilibrium heave in the same time period. FSI decreased from 185% to 63.63% when lime content was increased from 0% to 4%, and from 185% to 110% when cement content was increased from 0% to 20%. Swell potential reduced by 42.5% at 4% lime and by 46.4% at 20% cement. Swelling pressure increased from 210 kPa to 320 kPa when lime content was increased from 0% to 4%. Linear shrinkage of the specimens also decreased with increasing additive content.

Stabilization of Highway Expansive Soils with High Loss on Ignition Content Kiln Dust

This study was carried out to evaluate the effect of high loss on ignition content cement kiln dust on the stabilization of highway expansive soils. Laboratory tests were performed on the natural and stabilized soil samples in accordance with BS 1377 (1990) and BS 1924 (1990), respectively. The preliminary investigation carried out on the expansive soil (also known as black cotton soil) found in Deba, Gombe State, Nigeria shows that it falls under Silt-Clay material of Group A-7-6 (16) using AASHTO classification and inorganic clay material CL according to Unified Soil Classification System (USCS). The maximum dry density (MDD) for British Standard Light (BSL) and British Standard Heavy (BSH) compactive efforts increased to peak values of 1.66 and 1.91 Mg/m3 at 6% and 4% cement kiln dust (CKD) contents respectively. The MDD for West African Standard (WAS) compactive effort increased with higher CKD content. The Optimum Moisture Content (OMC) for BSL and BSH compactive efforts increased up to 6% CKD content then decreased with higher CKD content. For the WAS compactive effort, the OMC generally decreased with higher CKD content. The unsoaked California bearing ratio (CBR) values of 3, 5 and 7% for the natural soil compacted with BSL, WAS and BSH compactive efforts, respectively, increased to 7, 10 and 19% at 10% CKD content. The 24 hour soaked CBR values of the natural soil of 3% for BSL, 3% for WAS and 5% for BSH compactive energies, respectively increased to their peak values of 5%, 6% and 8% respectively at 10% CKD content.http://dx.doi.org/10.4314/njt.v33i2.1

Use of Posidonia Oceanica Ash in Stabilization of Expansive Soils

Posidonia oceanica (PO) is the most plentiful seaweed of the Mediterranean Sea, which grows all along the coastal areas, forming widespread meadows. The leaf rejuvenation process of Posidonia oceanica typically occurs in fall when an increase in wave action causes the dead seaweeds to be transported and usually piled up along the coastal areas. This paper investigates the effect of PO ash stabilization on behaviour of an expansive clay. The ash was obtained by combustion of crushed PO pieces in a muffle furnace at 550°C. Atterberg limits, linear shrinkage, particle size distribution, one-dimensional swell, and unconfined compression tests have been carried out on natural soil as well as soil mixtures with 5% and 10% PO ash. There has been no significant improvement in the soil properties with 5% ash inclusion, whereas 10% ash has noticeably reduced the swell amount and increased the compressive strength. It is therefore concluded that there is a potential for the use of PO ash in geotechnical engineering applications.

Strength Characterstics of Stabilized Embankment Using Fly Ash

Infrastructure projects such as highways, railways, water reservoirs, reclamation etc. requires earth material in very large quantity. In urban areas, borrow earth is not easily available which has to be hauled from a long distance. Quite often, large areas are covered with highly plastic and expansive soil, which is not suitable for such purpose. Extensive laboratory / field trials have been carried out by various researchers and have shown promising results for application of such expansive soil after stabilization with additives such as sand, silt, lime, fly ash, etc. As fly ash is freely available, for projects in the vicinity of a Thermal Power Plants, it can be used for stabilization of expansive soils for various uses. The present paper describes a study carried out to check the improvements in the properties of expansive soil with fly ash in varying percentages. Laboratory tests like 1) grain size analysis 2) atterberg limits 3) standard compaction 4) permeability test have been carried out on soil and CBR (California bearing ratio) test is conducted on soil sample mixed with fly ash in various proportions and results are reported in this paper. One of the major difficulties in field application is thorough mixing of the two materials (expansive soil and fly ash) in required proportion to form a homogeneous mass. The fly ash is mixed with soil in required proportion until the CBR value for the embankment is achieved.

Cement Kiln Dust Chemical Stabilization of Expansive Soil Exposed at El-Kawther Quarter, Sohag Region, Egypt

This work dealt with a chemical stabilization of an expansive high plastic soil of Pliocene deposits exposed at El-Kawther quarter using cement kiln dust (CKD) and cement kiln dust with lime (L) to reduce their swelling and improve their geotechnical properties. Several specimens of the studied expansive soil were collected from El-Kawther quarter. Chemical analysis of the used cement kiln dust and the lime was conducted. Microstructural changes were examined using scanning electron microscope (SEM) before and after chemical treatment of the studied soil. Geotechnical properties including plasticity, compaction parameters, unconfined compressive strength (qu), ultrasonic velocities and free swelling of the studied soil were measured before and after the treatment. An optimum content of the cement kiln dust was 16% (CKD). The optimum content of the cement kiln dust with the lime was 14% (CKD) with 3% (L) according to pH-test. The results showed that the addition of cement kiln dust and cement kiln dust with lime led to a decrease in maximum dry density and an increase in optimum water content. Unconfined compressive strength values were increased using cement kiln dust and cement kiln dust with lime at 7 days curing time. Ultrasonic longitudinal (Vp) and shear (Vs) velocities values were also increased by addition of the cement kiln dust and the cement kiln dust with lime at 7 days curing time. Increment of the curing time from 7 to 28 days led to an increase in both unconfined compressive strength and ultrasonic velocities values. Free swelling percent of the studied soil was reduced from 80.0% to 0.0% after the treatment.

Sulfate Induced Heaving of a Taxiway: A Case Study

Sulfate-rich soils are typically found in arid and semiarid regions in the United States and elsewhere. Sulfates are present in various forms such as gypsum or calcium sulfate, sodium sulfate, and magnesium sulfate. Stabilization of these sulfate rich expansive soils with calcium-based chemical stabilizers such as lime and/or cement becomes counterproductive due to the formation of highly crystalline expansive minerals namely ettringite and thaumasite. These minerals are the byproducts of the reactions between the sulfates, silicates and alumina present in the soil with the calcium component of the lime/cement. Both hydration reactions and crystal growth will result in a significant amount of heaving in the sulfate-rich soils. In this paper a few case studies are presented, in general, highlighting the damage caused to civil infrastructure by the sulfate induced heaving and heaving of a local airport taxiway in particular. In addition, remedial measures that were suggested to arrest this behavior are briefly mentioned.

In-situ stabilization of an expansive soil in desiccated state

This paper examines the efficiency of in-situ stabilization of expansive soil by lime slurry technique in desiccated state through laboratory and field experimental studies. The laboratory and field studies consists of permeating 34% hydrated lime slurry into the desiccated soil through vertical holes and measuring the physico-chemical, index and engineering properties before and after treatment at different radial distances. The distinct changes in the physico-chemical and index properties of the expansive soil indicate the occurrence of lime modification reactions and pozzolanic reactions on lime migration into the inter-connected shrinkage cracks. The lime slurry treatment increased the soil <i>pH</i> (≍ 12) to the levels that are conducive for the pozzolanic reactions to occur. The soil-lime reactions reduced the swelling potential and increased the unconfined compressive strength of lime slurry treated expansive soil. The test results encourage the application of lime slurry technique to expansive soil deposits during dry season upon development of shrinkage cracks.

Optimum fly ash for mechanical stabilization of expansive soils using 22 factorial experimental design

Numerous studies demonstrated the possibility of utilizing fly ash in the construction of embankments, road subgrades and stabilization of a wide range of soils. The present investigation aims at determining the optimum fly ash (OFA) for mechanical stabilization of expansive soils. Four different soils were tested for compaction characteristics and unconfined compressive strength with and without the addition of fly ash to determine the OFA. The liquid limit (LL) and the fraction coarser than 425 μ (CF) of these soils range from 50 to 120 and 25 to 70%, respectively. An experimental strategy called two-factor factorial design was adopted in the conducting experiments. LL and CF present in the soil are the two factors considered to influence the OFA content. Factorial experimentation enables relative quantification of the effect of each factor as well as their interaction with the OFA. The OFA was found to range from 5 to 40% depending upon the two factors. The LL and the CF were found to have dominating influence on OFA content in that order, whereas the interaction effect of these two factors was marginal to fair. A statistical regression model was developed for determination of the OFA in terms of the influencing factors. The validity of the model developed was verified by conducting laboratory tests on two more soils that were not used in the development of the model. Swell potential and swelling pressure of expansive soils were reduced to non-critical levels when treated with OFA.

Compaction of fills involving stabilisation of expansive soils

Stabilisation of sulphate-bearing soils with lime/cement-based binders has always been problematic, owing to excessive sulphate-induced expansion. This paper reports on investigations conducted on the consistency and compaction properties of Lower Oxford Clay (LOC), a sulphate-bearing soil that has been difficult to stabilise in the traditional manner using lime. In the investigations, LOC was stabilised both in the conventional manner using lime as the control, and also using a wide range of sustainable stabilisers incorporating industrial waste and by-product materials. The sustainable binders included wastepaper sludge ash (WSA) used on its own, as well as binary binders comprising WSA–lime, WSA–Portland cement (PC) and WSA–ground granulated blastfurnace slag. The results obtained showed that the blended stabilisers incorporating WSA were able to modify the soil by reducing the plasticity index, coupled with good compaction, strength and volume stability properties. The findings suggested that there are economic and environmental advantages of utilising WSA and similar industrial by-products in the modification and compaction of soils, including sulphate-bearing clay soils, as equal or at times superior alternatives to the traditional stabilisers of lime and/or PC.

Stabilization of expansive soils for use in construction

Expansive clay soils are extensively distributed worldwide, and are a source of great damage to infrastructure and buildings. These soils can cause heavy economic losses, as well as being a source of risk to the population. This article presents an experimental study in the stabilization of an expansive soil, consisting of the reduction of its swelling capacity and the improvement of its mechanical capacities by the addition of by-products and waste materials of industrial origin. This achieves the double objective of reducing the problems of this type of soil, and also of providing a use for the additives, thus eliminating the economic and environmental cost involved in managing them. From the point of view of expansivity, it was possible to reduce it to levels well below what Spanish legislation contemplates for expansive soils. As to the improved mechanical capacities of the soil, all treatments tested offered improvements of between two and four times the compressive strength of the untreated soil. Of the waste materials, the most notable is the behavior of Rice Husk Fly Ash, highly effective in stabilizing soil from the two aspects considered in this experiment.