Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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Item Establishing relationships for strength characteristics of lateritic soils with varying silt fractions(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2016) Kumar, A.; George, V.; Marathe, S.Design and construction of highway embankments constitute a major component of highway engineering science. Poor sub-grade strength, overloading due to traffic loads, and seismic vibrations can cause distress to pavement sub-grades and embankments. Inadequate compaction and poor sub soil drainage, in addition to low bearing strength of soils cause failure of embankments especially in submersible regions. The present study is focused on performing investigations on the engineering properties of lateritic and lithomargic soils and the effect of fines on soil strength. Tests such as California Bearing Ratio (CBR), tests for unconfined compressive strength (UCS), and tri-axial tests are carried to study the strength behavior of soil on addition of lithomargic soils. Additionally, the development of regressions will help field engineers in estimating the value of the CBR based on simple laboratory experiments such as Unconfined Compression strength test, and the Triaxial test. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Investigations on Bio-enzyme Stabilized Pavement Subgrades of Lateritic, Lithomargic and Blended Soils(Springer, 2023) Marathe, S.; Ravi Shankar, A.U.The pavement is a structure, which is laid to support the wheel load and to spread the load stress to a wider area on the top of the soil subgrade. The process of changing the engineering properties of natural soil, to improve its strength, bearing capacity and other engineering properties by the addition of suitable stabilizer and admixture is collectively known as stabilization of soil. It is very much essential to improve the soil strength, bearing capacity and other engineering properties to sustain the loads acting on the pavement. By modifying the subgrade soil properties, the crust thickness of the pavement reduces. This paper focuses on the effect of TerraZyme stabilization on three types of major soils available in the coastal Karnataka region. The study deals with the improvement in the engineering properties of these soils after subjecting to TerraZyme chemical stabilization. Initially, tests were carried out to study the mechanical properties like compaction, permeability, unconfined compressive strength (UCS) and California Bearing Ratio (CBR value). Further, the effect additions of TerraZyme chemical in various dosages to soil were observed in terms of their modified proctor compaction, UCS and CBR values. The curing effect on UCS and CBR was investigated. The structural design of pavement for the high-volume roads (as per IRC:37-2018) is proposed by strengthening the conventional subgrade soil layer with TerraZyme and the pavement analysis is carried out. © 2021, The Author(s), under exclusive licence to Chinese Society of Pavement Engineering.Item Stabilized Lithomargic Soil Subgrades for Low Volume Road Design Using Industrial Wastes(Springer, 2024) Marathe, S.; Bhat, A.K.; Ashmitha, N.M.; Akarsh, P.K.Lithomargic soil is considered a major group of “residual soil” which is identified as a problematic soil in the coastline region of Karnataka state of India. Previous studies reveal that the soil will cause several serious pavement deterioration problems when used as a pavement material. The present study focuses on the stabilization of this problematic shedi soil to make it suitable as a pavement subgrade material using fly ash (FA) and copper slag (CS) additives as stabilizers. In this investigation, various geotechnical properties were investigated to study the improvements in the mechanical soil properties with different percentages of FA and CS additions. For this investigation, relevant Indian standard (IS) codal guidelines were used. Initially, the effect of CS is studied by adding the various trial dosages of the CS from 0 to 50% (by weight) to the soil. The unconfined compressive strength (UCS) test revealed that the soil sample with 25% of CS has shown satisfactory results. Further, by maintaining the 25% CS dosage as constant, the FA dosage was introduced at an increment interval of 2% (by weight). The IS light compaction and UCS results revealed that a 6% dosage of FA had led to maximum strength gain. The improved mechanical performance includes an improvement in standard maximum proctor density from 15.22 to 18.16 kN/m3, soaked CBR value from 2.40 to 10.51%, and UCS value from 93 to 312 kPa. Further, the developments in the UCS and california bearing ratio (CBR) were studied by subjecting the virgin and modified soil to sustained desiccator curing at different intervals up to 56 days, the corresponding results indicated a strength gain of about 22% for the modified lithomargic soil. The durability tests were performed by subjecting the UCS specimens to alternate wetting–drying conditions and alternate freezing–thawing cycles. The test results were compared with that of the un-modified shedi soil. The test results were satisfactory for the application as the pavement subgrade material. The pavement design for the low-volume roads has been carried out using IRC: SP-72 guidelines and the pavement analysis is carried out using KENPAVE software. The results indicate that the use of 25% of CS along with 6% of FA in lithomargic soil could lead to a reduction of 46.15% of design pavement thickness and a reduced maximum deflection value upon stabilization. © The Author(s), under exclusive licence to Chinese Society of Pavement Engineering 2023.