Showing papers on "Soil stabilization published in 2014"

Upscaling Effects of Soil Improvement by Microbially Induced Calcite Precipitation by Surface Percolation

Abstract: This study has contributed to the technology of soil stabilization via biocementation based on microbially induced calcite precipitation. The newly described method of in situ soil stabilization by surface percolation to dry soil under free draining environment is tested for its up-scaling potential. Then, 2-m columns of one-dimensional trials indicated that repeated treatments of fine sand ( 0.5 mm) sand columns, allowing strength varying between 850 to 2067 kPa along the entire 2 m depth. Three-dimensional fine sand cementation trials indicated that relatively homogenous cementation in the horizontal direction could be achieved with 80% of cemented sand cementing to a strength between 2 to 2.5 MPa and to a depth of 20 cm. A simple mathematical model elucidated that the cementation depth was dependent on the infiltration rate of the ce...

Soil Stabilization Using Lime: Advantages, Disadvantages and Proposing a Potential Alternative

Abstract: This study is an overview of previous studies on lime (quick and hydrated) -treated soil. Lime is the oldest traditional stabilizer used for soil stabilization. The mechanism of soil-lime treatment involves cation exchange, which leads to the flocculation and agglomeration of soil particles. The high pH environment then causes a pozzolanic reaction between the free Ca^(+2) cations and the dissolved silica and alumina. Lime-treated soil effectively increases the strength, durability and workability of the soil. Such treatment also improves soil compressibility. A fluctuation behavior was observed on the influence of lime on soil permeability. However, the factors affecting the permeability of the soil-lime mixture should be extensively studied. Nonetheless, lime treatment has a number of inherent disadvantages, such as carbonation, sulfate attack and environment impact. Magnesium oxide/hydroxide are thus proposed as a suitable alternative stabilizer to overcome at least some of the disadvantages of using lime in soil stabilization.

Strength behavior and microstructural characteristics of tropical laterite soil treated with sodium silicate-based liquid stabilizer

Abstract: Although the effects of nontraditional stabilizers on the geotechnical properties of tropical soils has been the issue of investigation in recent years, the micro-structural characteristics of nontraditional soil additives and in particular selected additive (TX-85) have not been fully studied. Nontraditional soil stabilization additives are widely used for stabilizing marginal materials. These additives are low-cost alternatives to traditional construction materials and have different compositions. They also differ from one another while interacting with soil. In line with that, it was the objective of this research to investigate the strength properties and physicochemical mechanisms related to tropical laterite soil mixed with the liquid stabilizer TX-85. Macro-structure study, i.e., compaction, and unconfined compression strength test were used to assess the engineering and shear properties of the stabilized laterite soil. In addition, the possible mechanisms that contributed to the stabilization process were discussed using various spectroscopic and microscopic techniques such as X-ray diffractometry (XRD), energy-dispersive X-ray spectrometry, scanning electron microscopy, and Fourier transform infrared spectroscopy. From engineering point of view, the results indicated that the strength of TX-85 stabilized laterite soil improved significantly. The degree of improvement was approximately four times stronger than natural soil after a 7-day curing period. The XRD showed no crystalline products (gel form). Moreover, weathering effects were obvious in TX-85 treated samples in most of clay minerals’ peak intensities. These effects were reduced especially for kaolinite mineral inside the soil with curing time.

Development of Pervious Concrete Pile Ground-Improvement Alternative and Behavior under Vertical Loading

Abstract: Permeable granular columns are used to increase the time rate of consolidation, reduce liquefaction potential, improve bearing capacity, and reduce settlement. However, their behavior depends on the confinement provided by surrounding soil, which limits their use in very soft clays and silts, and organic and peat soils. This research effort aims to develop a new ground-improvement method using pervious concrete piles. Pervious concrete piles provide higher stiffness and strength that are independent of surrounding soil confinement while offering permeability comparable to granular columns. This proposed ground-improvement method can improve the performance of different structures supported on poor soils. To achieve the goal of the research project, four vertical load tests were performed on one granular column and three pervious concrete piles. In this paper, the material properties of pervious concrete, the developed installation method, and the vertical load response of pervious concrete and aggregate piles are presented, and the variation of soil stresses and displacement during pile installation are briefly discussed. The experimental test results show that the ultimate load capacity of the pervious concrete pile was 4.4 times greater than that of an identical granular column. In addition, the ultimate load capacity of a pervious concrete pile installed using the developed technique was 2.6 times greater than a precast pervious concrete pile. The used installation method created nonuniform lateral soil displacement and increased vertical and horizontal soil stresses.

Waste product 'bagasse ash' from sugar industry can be used as stabilizing material for expansive soils

Abstract: Soil is a base of structure, which actually supports the structure from beneath and distributes the load effectively. If the stability of the soil is not adequate then failure of structure occurs in form of settlement, cracks etc. Expansive soil also known as black cotton soil is more responsible for such situations and this is due to presence of montmorillonite mineral in it, which has ability to undergo large swelling and shrinkage. To overcome this, properties of soil must be improved by artificial means known as ‘Soil Stabilization’. It is a technique which improvises one or more soil properties by mechanical, cementing and chemical use. Many research has been conducted for stabilization of soil by using cementing, chemical materials e.g. Fly ash, cement, Calcium chloride, Sodium chloride etc. Toady world is facing serious problem of disposal of agricultural waste. Western Maharashtra is popular for production of sugar cane in large quantity. Sugar factories produces waste after extraction of sugar cane in machines that waste when burnt, the resultant ash is known as ‘Bagasse Ash’. It is a fibrous material with presence of silica (SiO2) and can be used to improve the existing properties of black cotton soil. In this study laboratory experiments were conducted on black cotton soil with partial replacement by Bagasse Ash (3%, 6%, 9% and 12%). This paper highlights significant increase in properties of black cotton soil obtained at 6% replacement of Bagasse Ash without any chemical or cementing material.

Soil Stabilization Using Waste Shredded Rubber Tyre Chips

Abstract: Construction of engineering structures on weak or soft soil is considered as unsafe. Improvement of load bearing capacity of the soil may be undertaken by a variety of ground improvement techniques. In the present investigation, shredded rubber from waste has been chosen as the reinforcement material and cement as binding agent which was randomly included into the soil at three different percentages of fibre content, i.e. 5% 10% and 15% by weight of soil. The investigation has been focused on the strength behaviour of soil reinforced with randomly included shredded rubber fibre. The samples were subjected to California bearing ratio and unconfined compression tests. The tests have clearly shown a significant improvement in the shear strength and bearing capacity parameters of the studied soil. The results obtained are compared with unreinforced samples and inferences are drawn towards the usability and effectiveness of fiber reinforcement as a replacement for deep or raft foundation and on pavement subgrade soil as a cost effective approach. The low strength and high compressible soft clay soils were found to improve by addition of shredded rubber and cement. It can be concluded that shredded rubber fibre can be considered as a good earth reinforcement material.

Behaviour of Lime Treated Cured Expansive Soil Composites

Abstract: Expansive soils have the tendency to undergo volume change behavior and cause large uplift pressures and upheaval of structures built on them. Avoiding expansive soil in most of the cases is not practically possible, hence stabilization practices are undertaken to treat them. Chemical stabilization through lime is the most sought after treating method. In this study, soil from an expansive soil site, Siruseri near Chennai, was treated with lime to understand the microstructural changes taking place and its influence on the macro structural properties. X-ray diffraction, SEM and microporosimetry were the techniques used to understand the microstructural properties of lime treated soils. The expansive soil was treated with different percentage of lime, 2, 4, 6, and 8 % and cured for 3, 7, 14, and 28 days. The concept of lime modification optimum (LMO) was used as a reference to understand the progression of lime reactions. The change in the physical properties of the soil was determined through UCC, chemical batch testing, pH and chemical conductivity. The lime addition higher than the LMO brings about more permanent pozzolanic reactions which cause tremendous increase in strength. The time dependency of the reactions was observed through the change in pH values, conductivity and batch test results. At the microstructural level, lime addition reduces the specific surface area and increases the pore size. The SEM results also revealed larger clusters and aggregation of the clay particles.

Addition of Lime and Fly Ash to Improve Highway Subgrade Soils

Abstract: Laboratory tests have been carried out in order to evaluate the improvement in engineering properties relevant to highway design and construction obtained when clayey subgrade soils are stabilized with lime or fly ash. The experimental program included California bearing ratio (CBR) tests to evaluate the bearing strength of stabilized soils used as working platforms during highway construction. The admixture of lime or fly ash caused an increase in the plasticity limit, while both the liquid limit and the plasticity index of the soils have been reduced. Substantial increases in the California bearing ratio value, higher than those of the soil–fly ash mixtures, have been obtained when the soil samples were mixed with lime. The swelling after a 4-day soaking period has been reduced with the addition of both additive materials. The increase in optimum moisture content acts subsidiarily to the increased CBR value, particularly at high lime or fly ash percentages. An analogous effect has been found for...

Soil Stabilization By Using Fly Ash

Abstract: Soil is a peculiar material. Some waste materials such Fly Ash, rice husk ash, pond ash may use to make the soil to be stable. Addition of such materials will increase the physical as well as chemical properties of the soil. Some expecting properties to be improved are CBR value, shear strength, liquidity index, plasticity index, unconfined compressive strength and bearing capacity etc. The objective of this study was to evaluate the effect of Fly Ash derived from combustion of sub-bituminous coal at electric power plants in stabilization of soft fine-grained red soils. California bearing ratio (CBR) and other strength property tests were conducted on soil. The soil is in range of plasticity, with plasticity indices ranging between 25 and 30. Tests were conducted on soils and soil-Fly Ash mixtures prepared at optimum water content of 9% .Addition of Fly Ash resulted in appreciable increases in the CBR of the soil. For water contents 9% wet of optimum, CBRs of the soils are found in varying percentage such that 3,5,6and 9.We will found optimum CBR value of the soil is 6%.Increment of CBR value is used to reduce the thickness of the pavement. And increasing the bearing capacity of soil.

Applicability of Municipal Solid Waste Incineration Ash on Base Layers of Pavements

Abstract: This study presents the characteristics of municipal solid waste (MSW) incineration ash obtained from an electric energy generation plant and evaluates the MSW ash applicability in base road pavement layers through the mixture of ash with a nonlateritic regional clay soil. Chemical, physical, and mechanical tests and the mechanistic-empirical design for a typical pavement structure were carried out on the pure soil and also in the soil mixture with the addition of different ash content (20 and 40%). Fly ash reduced the expansion of the material, showing an increase in the California bearing ratio (CBR) and resilient modulus value. The results are satisfactory, depending on the content and type of ash used, highlighting the positive work of MSW fly ash for its use in base road pavement layers.

Geosynthetic Engineering and Vegetation Growth in Soil Reinforcement Applications

Abstract: In Italy, since early times, the environmental aspects have always been a key issue on the design and the application. Consequently, the geosynthetic reinforced soil structures consist of vegetated face steep slopes. Furthermore, the use of vegetation has also been recognized and incorporated in engineering practice for erosion control and for stabilization of shallow slopes. Vegetation influences slope stability and erosion process by both mechanical effects and hydrological effects. In particular, in the paper, the mechanical effects of vegetation related to soil stabilization will be described. The purpose of this paper is to present the specific role of vegetation in soil reinforcement applications, by means of the analysis of the available literature on the (i) factors affecting root reinforcement of soil, (ii) experimental tests carried out on roots and on roots-soil system, and (iii) analytical and theoretical models. The erosion applications will not treated in this paper. The use of vegetation in civil engineering and landscape works has grown in importance, even if the specific design standard concerning the use of vegetation for slope stabilization is still under discussion. Therefore, design and management of stabilization systems by plants require an accurate knowledge about the quantitative reinforcing root effects on soil strength.

Effect of bio-enzyme stabilization on unconfined compressive strength of expansive soil

Abstract: Engineers often face the problem of constructing facilities on or with soils, which do not posses sufficient strength to support the loads imposed upon them either during construction or during the service life of the structure. Vast areas of India consist of Black Cotton Soil which has high clay content, low strength and minimal bearing capacity. The poor engineering performance of such soils has forced Engineers device cost effective and ecofriendly methods for improving the engineering properties of poor soils. As the conventional soil stabilizers like gravel, sand, etc. are depleting and becoming expensive day by day at a very rapid pace, it becomes necessary to look towards for alternative ecofriendly stabilizers as their substitute. Recently many Bio-enzymes have emerged as cost effective stabilizers for soil stabilization. One such bio-enzyme, Terrazyme, has been used in the present work to study its effect on the Unconfined Compressive strength of the Black Cotton soil. It has been found that Terrazyme treated Black Cotton soil shows significant increase in Unconfined Compressive strength with longer curing period.

A geoenvironmental application of burned wastewater sludge ash in soil stabilization

Abstract: This paper studied the use of burned sludge ash as a soil stabilizing agent. The sludge ash was obtained from a public wastewater treatment plant, and it was burned at 550 °C. Different percentages of burned sludge ash were mixed with three different types of clayey soil. A laboratory study consisting of Atterberg’s limits test, unconfined compressive strength test, standard proctor density test, and swelling pressure test were carried out on samples treated with burned sludge at different percentages by dry weight of the clayey soils. The results show that the addition of 7.5 % of the burned sludge ash by the dry weight of the soil will increase the unconfined compressive strength and maximum dry density and also decrease the swelling pressure and the swell potential of the soil. The addition of percentage higher than 7.5 % by dry weight of the soil decreases both the maximum dry density and the unconfined compressive strength; as a result it showed less effectiveness in stabilizing the soil. The conclusion of this research revealed that the burned sludge ash can be used as a promising material for soil stabilization.

Evaluation of Sawdust Ash-Stabilized Lateritic Soil as Highway Pavement Material

Abstract: Large quantities of sawdust waste are generated daily by the logging and lumbering industries, and their safe disposal is a major concern worldwide, whereas the properties of some lateritic soils make them undesirable for use in engineering construction. This paper presents the results of a laboratory evaluation of the characteristics of lateritic soil (LS) stabilized with sawdust ash (SDA), subjected to British standard light (BSL) compactive effort to determine their index, compaction, unconfined compressive strength (UCS), and California Bearing Ratio (CBR) results. The results of the laboratory tests show that the properties of LS improved when stabilized with SDA. The particle-size distribution improved from poorly graded, sandy, gravelly material for 100% lateritic soil and silty material for 100% SDA to the gradation with 94.9–99.9% coarse aggregates of sand and gravel, described as gravelly sand and sandy gravel material for SDA-stabilized LS. The CBR results obtained from the study show t...

Effect of phosphogypsum on strength of lime stabilized expansive soil

Abstract: The use of phosphogypsum as an additive to lime, to enhance its performance in soil stabilization, is analyzed in this paper. Phosphogypsum is a by-product of the phosphate rock processing during production of phosphoric acid. Expansive soil samples used in this paper were stabilized using three different lime proportions: initial lime consumption, optimum lime content, and less than initial lime consumption. The results reveal that the addition of phosphogypsum to lime led to improvement of both the early and late strength of stabilized soil.

Design and Construction Guidelines for Deep Soil Mixing to Stabilize Expansive Soils

Abstract: This paper discusses both design methodology and construction procedures for stabilizing expansive subsoils of moderate active depths, using deep soil mixing (DSM) technology/construction. These procedures were derived as a part of the research focusing on the evaluation of effectiveness of DSM technology in mitigating shrink-and-swell behaviors of expansive subsoils under actual field conditions. The design methodology formulated was based on an analytical model proposed for a DSM-treated composite section by modifying the existing heave prediction model for untreated and unsaturated expansive soils. The required area treatment ratio was determined based on the target heave magnitude for the composite section. Design charts were developed depicting estimated heave for increasing treatment area ratios and for various initial swell pressures. Based on this design methodology, DSM construction was implemented under actual field conditions at two test sites. Upon construction, both test sections were...

Potential Uses of Sewage Sludge in Highway Construction

Abstract: The sewage treatment plants generate, as by-products, large amounts of sludge containing harmful elements to the environment. This paper investigates the possibility of using 10% of sewage sludge by weight in pavement base layers. The soil stabilization technique was used to improve the residue properties to satisfy the minimum requirements for road bases. The intent of this stabilization technique was to use conventional additives as cement, lime, and emulsion. The main objective was to evaluate the strength behavior of the modified soil. Sludge-soil mixtures with different additive contents (2, 4, 6, and 8%) were prepared for testing. The modified soil samples were subjected to compaction, and then tested for the following parameters: California bearing ratio, unconfined compressive strength, indirect-tensile strength, resilient modulusa, and deterioration tests. Mechanical tests were used to estimate the optimum mix design. Test results indicated that the stabilization of mixtures of soil with ...

A review on stabilization of soil using bio-enzyme

Abstract: In developing countries like India the most importa nt requirement of any project after performance cri teria is its economical feasibility and serviceability criteria. The conven tional methods are time consuming and are not econo mically feasible. Hence there is a need to discover the other possible ways to satis fy the performance as well as economical criteria. In this paper, popularly available bio-enzymes and their effect on engineering propert ies of soil are discussed. The stabilization of soil with bio-enzyme is a revolutionary technique which becoming popular worl dwide. Recently there are many bio-enzymes availabl e for soil stabilization such as renolith, Perma-Zyme, Terra-Zyme, Fujibeton etc. These enzymes have been proven to be very ef fective and economical. Another advantage of the bio-enzyme is that these a re environment friendly. When these bio-enzymes are mixed with soil they alter its engineering properties. Their efficiency depends up on the amount of dose, type of soil available and f ield conditions. The use of bioenzyme in soil stabilization is not very popular due to lack of awareness between engineers and non availability of standardized data. However, recently some bio-enzyme stabilized roads were constructed in various parts of India, w hich are performing very well.

Behavior of Clayey Soil Stabilized with Rice Husk Ash & Lime

Abstract: In India the soil mostly present is Clay, in which the construction of sub grade is problematic. In recent times the demands for sub grade materials has increased due to increased constructional activities in the road sector and due to paucity of available nearby lands to allow excavate fill materials for making sub grade. In this situation, a means to overcome this problem is to utilize the different alternative generated waste materials, which cause not only environmental hazards and also the depositional problems. Keeping this in view stabilization of weak soil in situ may be done with suitable admixtures to save the construction cost considerably. The present investigation has therefore been carried out with agricultural waste materials like Rice Husk Ash (RHA) which was mixed with soil to study improvement of weak sub grade in terms of compaction and strength characteristics. Silica produced from rice husk ashes have investigated successfully as a pozzolanic material in soil stabilization. However, rice husk ash cannot be used solely since the materials lack in calcium element. As a result, rice husk ash shall be mixed with other cementitious materials such as lime and cement to have a solid chemical reaction in stabilization process. Lime is calcium oxide or calcium hydroxide. It is the name of the natural mineral (native lime) CaO occurs as a product of coal seam fires and in altered lime stone xenoliths in volcanic ejection. In this study RHA and Lime is mixed in different percentage like (RHA as 5%, 10%, and 15%) and (Lime as 3%, 6%, 9%) and laboratory test CBR is done with a curing period of 4, 7 and 14 days with different percentages of RHA & Lime

Stress Dilatancy and Reinforcement Load of Vertical-Reinforced Soil Composite: Analytical Method

Abstract: A straightforward analytical method is proposed to calculate the reinforcement loads of vertical-reinforced soil composites before the strength of soil is fully mobilized. The method assumes compatibility of soil and reinforcement deformations along the potential failure surface. It makes use of the nonlinear stress-strain relationship of soil in a plane-strain condition and Rowe’s stress-dilatancy relationship. It has the advantage of taking into account the soil dilatancy before failure and can properly estimate the reinforcement load with small or medium soil deformation. The effect of soil compaction on the reinforcement load is taken into account through an elastic unloading/reloading approach. The method was first validated against the results of a calibrated numerical analysis. It was then used to predict the reinforcement loads of two large-scale tests. The proposed method has the potential to fully develop into an analytical method for reinforced soil retaining walls, provided that effect...

Use of Live Poles for Stabilization of a Shallow Slope Failure

Abstract: Soil bioengineering methods consisting of live poles and brush layers were used to stabilize shallow slides and control erosion on an embankment slope in eastern Ohio. Plant survival rates, slope movement, soil moisture content, and soil suction were measured. Load tests were performed to evaluate resistance of the poles, and results were used to estimate the stability of the repaired slope. Seven years after the repair was completed, vegetation is well established and the slope is stable, which is in agreement with calculated safety factors. This study indicates that soil bioengineering methods can be used for stabilization of shallow failures; however, the method may not be immediately effective, and the time of installation and soil moisture conditions are important for survival of the poles.

Analysis of Engineering Properties of Black Cotton Soil & Stabilization Using By Lime.

Abstract: With the increasing of population and the reduction of available land, more and more construction of buildings and other civil engineering structures have to be carried out on weak or soft soil. Owing to such soil of poor shear strength and high swelling & shrinkage, a great diversity of ground improvement techniques such as soil stabilization and reinforcement are employed to improve mechanical behavior of soil, thereby enhancing the reliability of construction. Black cotton soil is one of the major soil deposits of India. They exhibit high swelling and shrinking when exposed to changes in moisture content and hence have been found to be most troublesome from engineering considerations. Stabilization occurs when lime is added to black cotton soil and a pozzolanic reaction takes place. The hydrated lime reacts with the clay particles and permanently transforms them into a strong cementations matrix. Black cotton soil showing low to medium swelling potential from Rajkot Gujarat was used for determining the basic properties of the soil. Changes in various soil properties such as Liquid limit, Plastic Limit, Maximum Dry Density, Optimum Moisture Content, and California Bearing Ratio were studied.

Effect of lime and rice husk ash on engineering properties of black cotton soil

Abstract: Black Cotton Soils exhibit high swelling and shrinking when exposed to changes in moisture content and hence have been found to be most troublesome from engineering considerations. This behavior is attributed to the presence of a mineral montmorillonit. The wide spread of the black cotton soil has posed challenges and problems to the construction activities. To encounter with it, innovative and nontraditional research on waste utilization is gaining importance now a days. Soil improvement using the waste material like Slags, Rice husk ash, Silica fume etc., in geotechnical engineering has been in practice from environmental point of view. The main objective of this study is to evaluate the feasibility of using Rice Husk Ash with lime as soil stabilization material. A series of laboratory experiment has been conducted on5%lime mixed black cotton soil blended with Rice Husk Ash in 5%, 10% 15% and 20% by weight of dry soil. The experimental results showed a significant increase in CBR and UCS strength. The CBR values increases by 287.62% and UCS improved by30%.The Differential free swell of the black cotton soil is reduced by 86.92% with increase in Rise Husk Ash content from 0% to 20% respectively. From this investigation it can be concluded that the Rice Husk Ash has a potential to improve the characteristics of black cotton soil.

Stabilization of marine clay by biomass silica (non-traditional) stabilizers

Abstract: The presence of marine clay in Iskandar Malaysia Region, Nusajaya had caused expensive solutions in the construction of structures and roads. Alternatively, soil treatment is suggested to increase the strength of the unsuitable material to meet the constructions requirement for foundation and also to achieve the specifications for development work. In this study, a series of laboratory test has been conducted to determine the potential of Biomass Silica (BS), one of the commercial brands namely “SH-85” to stabilize marine clay to form the basis of a strong, reliable land for construction of roads and building. Testing program involves obtaining specimens of marine clays from various locations at Iskandar Malaysia Region, followed by laboratory tests to determine the Atterberg limits and Unconfined Compressive Strength (UCS) for treated and untreated of marine clay soils. The proportions of BS added were 3, 6, 9, 12 and 15% and tested at 0, 3, 7 and 28 days curing periods. The results shows that the Plasticity Index (PI) was reduce with increment of BS content. While, an addition of BS content increase in strength treated soils 60 times more than untreated soils, which is gain in early 7 curing days period. This finding indicates the BS is a suitable stabilizer for the marine clay to become strong foundation for construction of road and building.

Engineering properties of expansive clayey soil stabilized with lime and perlite

Abstract: There are around 6700 millions tons of perlite reserves in the world. Although perlite possesses pozzolanic properties, it has not been so far used in soil stabilization. In this study, stabilization with perlite and lime of an expansive clayey soil containing smectite group clay minerals such as montmorillonite and nontronite was investigated experimentally. For this purpose, test mixtures were prepared with 8% of lime (optimum lime ratio of the soil) and without lime by adding 0%, 10%, 20%, 30%, 40% and 50% of perlite. Geotechnical properties such as compaction, Atterberg limits, swelling, unconfined compressive strength of the mixtures and changes of these properties depending on perlite ratio and time were determined. The test results show that stabilization of the soil with combination of perlite and lime improves the geotechnical properties better than those of perlite or lime alone. This experimental study unveils that the mixture containing 30% perlite and 8% lime is the optimum solution in stabilization of the soil with respect to strength.