scholarly journals Attentive Study on Strength Characteristics of Expansive Soils on Subgrade of Express Highways by utilisation of RBI Grade-81 and Local Polymers

Author(s):  
Kuppili Harish Dr. Ch Bhavannarayana,

Chemical stabilization is one of the oldest methods of stabilization of problematic soil. In recent days, it has been investigated that addition of fibers will improve the ductility behavior of the soil there by reducing the development of crack during shrinkage. Extensive study has been carried out on the stabilization of expansive soils using various additives such as RBI, cement, flyash, industrial waste products etc., and also with random inclusion of fibers such as coir, sisal, polyester fibers etc. Randomly oriented tensile inclusions incorporated into soil to improve its load–deformation behaviour by interacting with the soil particles mechanically through surface friction and Effect of Random Inclusion of Coir Fibers on Strength Behaviour of RBI Treated Black Cotton Soil. This project describes the strength behavior of treated black cotton soil (BC soil) reinforced with local fiber. The various percentage of RBI Grade-81 as 2%, 4%, 6% and 8% was used to find out the optimum value of RBI Grade. local polymer has been randomly included into the RBI Grade treated soil at four different percentages of local fiber content, i.e. 0.5%, 1% 1.5%, and 2% (by weight of soil).

Expansive soils are problematic soils for Civil Engineers. Black cotton (BC) soils possess low strength and high compressibility, due to these properties black cotton soils are considered to be challenging one for analysis. To achieve desired properties of soil for construction purpose these black cotton soil must be enhanced to meet its requirement. To modify the properties of black cotton soils, many treatment methods are there. In this paper an attempt has been made to improve the properties of black cotton soil by using industrial waste through stabilization method. By stabilizing the soil properties are enhanced and make it suitable for subgrade construction. In this work, the combined effect of Lime and Phosphogypsum (PG) on compaction characteristics, Atterberg’s Limit, Unconfined Compressive Strength (UCS) for original soil, California Bearing Ratio (CBR) and direct shear Test of a black cotton soil with percentage varying of Lime and Phosphogypsum was carried out. The soil samples were tested for tri-axial compression test and CBR tests were carried out after 4 days curing period. From the results, it has been inferred that the black cotton soil treated with Lime and Phosphogypsum in the percentages of (4:4) has better strength characteristics. Hence, it may be concluded that Lime and Phosphogypsum can be used for stabilization of black cotton soils for pavement subgrade


2010 ◽  
Vol 2 (1) ◽  
pp. 19-28 ◽  
Author(s):  
H.N. Ramesh ◽  
K.V. Manoj Krishna ◽  
H.V. Mamatha

2021 ◽  
Vol 1197 (1) ◽  
pp. 012077
Author(s):  
K.S Chamberlin ◽  
M. Rama Rao

Abstract Expansive soils are found in black cotton soils, which swell or shrink in volume when presented to changes in moisture content. Lime treatment is exhaustively used to increment the properties of sensitive and fragile soils. One of the hugest clarifications behind using lime is to decline the developing presentation of the earth soil. The arrangement of extra safeguards improves the reaction of quicklime (CaO) with water, structures hydrated (slaked) lime (Ca (OH)2), and thus earth characteristics. The vast inadequacy of employing lime is growing the deficiency of lime offset earth. Following that, the goal of this study is to see how re-establishing time affects the geotechnical qualities of settled Black cotton soils with lime. These discoveries recommend that adding Lime as a stabilizer works on the strength of black cotton soil. Some of the characteristics of the soil likely to be increased by using stabilizer in this work are UCS (Unconfined Compressive Strength) at different curing periods (7,14,28 and 56 days), CBR (California Bearing Ratio) value at unsoaked and soaked and MDD (Maximum Dry Density) decrease at different lime percentages(%) like 2.4.6.8 and 10. The result showed here untreated soil got stabilized by using the stabilizer in certain extent In this adjustment various rates of cementitious material is added to black cotton soil and directed tests like plasticity, compaction, swell pressure, free swell index(FSI), Coefficient of permeability (k) and CBR(soaked and unsoaked) at various conditions like OMC,OMC+2% water and OMC+5% water, UCS (Unconfined Compressive Strength) was performed. From the test results, it is identified that the stabilization agent decreases plasticity and improves strength characteristics. Addition of stabilizing agent makes the black cotton soil to non-plastic, non-swelling and attains increase CBR values which are greater than 25% for a dosage of 10% lime at OMC but remaining OMC+2%water & OMC+5%water CBR values are not various much difference as per test results. With the addition of lime, the black cotton soil becomes non-plastic, non-swelling, and has high strengths. Treated soils are used as a development material, for example, a subgrade layer in the development of adaptable asphalt pavements for roads.


2018 ◽  
Vol 2 (6) ◽  
pp. 383 ◽  
Author(s):  
Arinze Emmanuel Emeka ◽  
Agunwamba Jonah Chukwuemeka ◽  
Mama Benjamin.Okwudili

This study was carried using finite element software (Plaxis) in studying the Engineering behavior of erodible soil-quarry dust composite at a proportion of 50% quarry dust and 10% cement. It discusses the effects of decorative street light through numerical analysis using the Finite Elements Method. Plaxis program v8.2 was applied to model the soil behavior. The Mohr-Coulomb model reveals that the deformations are concentrated exclusively on the base course, with the appearance of plastic tension cut-off points on base course. The structure was subjected to double point loads of 50 kN/m each which resulted to 100 kN/m. The results shows that the pavement deformed at load 85.16kN/m which showed that the soil strength cannot withhold the pressure from the street light. The load displacement acting on the base of the highway in study is . The result also shows that failure was concentrated at the base course of the pavement. This was due to the presence of underground water beneath the phreatic level. The quarry dust is a good replacement to weak soil or a good additive to help improved a problematic soil. From analysis, the soil strength lies below the effective stress acting on the pavement which is equal to 85.16 kN/m. It is advisable to replace some quantities of the existing soil and be replaced by quarry dust since quarry dust is a waste product from crushing of stones. Lastly, about 30% of the existing soil should be replaced by either the mixture of lateritic soil and quarry dust or the soil there should be used as subbase which may not be economical.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Rama Vara Prasad Chavali ◽  
B. Reshmarani

Abstract The current study examines the potential of lignosulfonate to enhance the engineering behavior of two locally available expansive soils. The expansive soils were collected from Vijayawada and Amaravathi, located in the Capital Region of Andhra Pradesh, India. The soils were treated with four different percentages (0.5, 1, 2, and 4) of lignosulfonate and were allowed to interact for 7 and 28 days. A series of laboratory tests such as unconfined compressive strength, cation exchange capacity and scanning electron microscopy were carried out on the soil specimens. The results indicated that lignosulfonate has significant influence on the strength behavior of expansive soils. The amount of fines content present in soils defines the optimum percentage of lignosulfonate. Lignosulfonate treatment resulted in reduced negative surface charge of soils and formation of Polymer chain microstructure along with flocculated or aggregated particle microstructure, which may attribute to the enhanced strength of the expansive soils.


From the fast few decades, several techniques were introduced inorder to modify the behaviour of expansive clays. The use of strong electrolytes like calcium chloride (CaCl2 ), aluminum trichloride (AlCl3 ) and iron chloride (FeCl3 ) were extensively used in various civil engineering applications. Expansive soils possesses alternate shrinkage and swelling with the removal and addition of water from it. Iron chloride was effectively used to alter the swelling and shrinkage and also improve the engineering behaviour of expansive clays. Therefore, in the current work an effort is made for study the influence of iron chloride (FeCl3 ) on the strength behaviour of the expansive soil. The outcomes from the laboratory investigation proved that the usage of iron chloride (FeCl3 ) produce reduction in swelling and improvement in the strength. It was found that 1% FeCl3 be the optimum for both the UCS and CBR. Hence, from the investigation it was showed that iron chloride is a valuable stabilizer to enhance the properties of black cotton soil and to create it apt for various applications of Civil Engineering.


2020 ◽  
Vol 8 (5) ◽  
pp. 1781-1785

Stabilization of black cotton soil is a challenging task for geotechnical engineers since such soil is highly vulnerable to expansive characteristics when the moisture content is increased. Due to its expansive nature, it is also called as swelling or expansive soils. Among the clay minerals, Montmorillonite is mainly responsible for such expansive characteristics. Bore log profile has a cluster of soil specimens including black cotton soil also which is unavoidable. Soil engineers have a serious concern about such expansive soil since it is treacherous for foundation of buildings. To overcome such deficiencies it becomes essential to stabilize the soil conditions. The commonly employed methods to decrease the expansive behaviour are: Chemical stabilization, Mechanical stabilization and installation of moisture barriers. In this paper, chemical stabilization method is adopted. Soil stabilizers, namely, sodium silicate, epoxy resin and polyvinyl alcohol are chosen and are mixed with black cotton soil in varying proportions of 5%, 10% and 15% to study the changes in geotechnical properties. From the results it is evident that polymer treated soils reduce plasticity characteristics and shows better results in geotechnical properties.


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