Faculty Publications
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Item Experimental Studies on Lateritic Soil Stabilized with Cement, Coir and Aggregate(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Ravi Shankar, A.U.R.; Priyanka, B.A.; AvinashThe characteristics of subgrade soil play a vital role in designing the pavement structure so that the pavement has required support from the bottom layer. During adverse weather conditions and higher traffic loads moving on any pavement, it should be able to withstand the impact and perform well for longer duration. Load is transmitted from pavement to the subgrade layer and distributed evenly through the soil particles. All types of soil are not capable of handling such impacts by their own and needs additional stabilization processes. Several stabilization processes are available in which the best one has to be taken into consideration. Fibers such as coconut coir are important in giving extra stability to the soil particles. Cement is well-known material in construction sector along with aggregates. Lateritic soil is available abundantly in coastal areas of southern parts of India which has porous structure and demands stabilization when the intended purpose is specific and requires higher strength and durability. In this study, coconut coir along with cement and aggregate are taken as stabilization materials to stabilize lateritic soil. Initially, basic properties of soil like plastic limit, liquid limit and plasticity index are determined. Grain size analysis is done and modified Proctor test is conducted to determine the optimum moisture content (OMC) and maximum dry density (MDD) of the soil. Unconfined compression test (UCS), California bearing ratio test (CBR), flexural fatigue analysis, durability properties with respect to wet-dry cycles and freeze–thaw cycles are evaluated for untreated and treated soil specimen. As per UCS values, cement can be taken at an optimum dosage of 6%. The coir fibers from natural husk of coconut and aggregates of 10 mm below size were added to the soil–cement mixes and an optimum dosage of coir and aggregate is determined. The study showed positive results in terms of CBR values of cement-aggregate treated soil. © 2021, Springer Nature Singapore Pte Ltd.Item Compressive Strength of High Plastic Clay Stabilized with Fly Ash-Based Geopolymer and Its Synthesis Parameters(Springer Science and Business Media Deutschland GmbH, 2021) Neeraj Varma, N.; Kumar, T.; Thotakura, V.Geopolymerization is an effective technique for utilizing industrial solid waste material as stabilizing material. This paper studies the effect of class-F fly ash-based geopolymer on compressible strength characteristics of high plastic clay using unconfined compression strength (UCS) test. Sodium silicate and sodium hydroxide were used as alkali activators in proportions of 60:40, respectively. The fly ash content was varied by 0, 10, 20 and 30% by dry weight of soil, and alkali activator was varied by 5, 10 and 15% by dry weight of soil–fly ash mix. UCS tests were carried out on the specimens contaminated under controlled curing environment. Unconfined compression strength increased with increase in fly ash and liquid activator content. The maximum UCS value of 790 kPa observed at 30% of fly ash content under elevated temperature of 50 °C. The influence of Si/Al and Na/Al ratios on compressive strength of geopolymeric materials was also identified. Further, numerical analysis was carried out to check the significance of factors effecting the compressive strength of the material. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Improvement in the Properties of Red Soil Using Granulated Blast Furnace Slag(Springer Science and Business Media Deutschland GmbH, 2022) Preetham, H.K.; Nayak, S.; Jagapur, P.In the current study, an attempt is made to improve the geotechnical properties of red soil using industrial by-product: Granulated-Blast Furnace Slag (GBFS). Red soil is distributed over large part of the peninsular region in India. Red soil could be effectively stabilized to yield better strength characteristics. GBFS is the primary by-product of the iron and steel industry. Red soil was replaced with varying percentages of admixture (GBFS) by dry weight of soil (5, 10, 15, 20 and 30%). Basic geotechnical properties like specific gravity, Atterberg limits, compaction, unconfined compressive strength (UCS) and triaxial compression test, were performed on the red soil as well as on the mixes as per Indian Standard Codal provisions. From the UCS test results, the optimum percentage of replacement of 15% was found. It was observed that on replacement with admixtures, the liquid limit was found to decrease which reduces the compressibility. The presence of CaO in GBFS has improved the shear strength and shear strength parameters of soil. Thus utilization of granular industrial by-product (GBFS) has proven beneficial in geotechnical structures. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Assessment of the Geotechnical Properties of Red Earth Stabilized Using Quarry Dust and Cement(Springer Science and Business Media Deutschland GmbH, 2022) Nayak, S.; Preetham, H.K.; Prakash, S.D.The present investigation aims at improving the engineering properties of red earth by incorporating quarry dust (QD) and analyze the results thus obtained by conducting a comparative study with the basic soil. Red earth is widely spread over a large part of peninsular India. Red earth/red soil could yield better results by the addition of rough-textured granular quarry dust and a hydraulic binder like cement. QD is the output from the rubble crushing units. Red earth was replaced with different proportions of quarry dust by dry mass of the soil: QD (5–30%, with an increment of 5%) with cement (2–6%) for the optimum QD-soil mix. The geotechnical properties like specific gravity, consistency limits, compaction, unconfined compressive strength (UCS), and triaxial compression test were performed on the red earth as well as on the mixes as per Indian Standard Codal provisions. UCS test results conclude that an optimum percentage of replacement of red earth by QD is 10% which yielded maximum strength than other mixes. It was observed that on replacement of red earth by granular quarry dust and cement, the shear strength properties and other geotechnical properties were improved. Thus, the utilization of granular industrial by-products has proven to be socially and economically beneficial. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Laboratory Investigation of Lateritic Soil Stabilized with Arecanut Coir Along with Cement and Its Suitability as a Modified Subgrade(Springer Science and Business Media Deutschland GmbH, 2023) Chethan, B.A.; Lekha, B.M.; Ravi Shankar, A.U.If a pavement is constructed on weak soil, its lifespan drastically reduces due to the low strength induced by moisture-induced destresses. Such soils may undergo considerable changes in volume. In order to modify these properties, soil stabilization can be done. By stabilizing the soil along with the improvement in strength, its durability can be increased. Stabilization may be of chemical or mechanical type. In this investigation, lateritic soil was stabilized using 0.2–1% arecanut coir, and its compaction characteristics were evaluated. The lateritic soil is found to be nondurable. The reinforcement alone could not improve the strength and durability effectively. Therefore, 3% binding agent ordinary Portland cement (43 grade) was added to the mix. Due to cement stabilization, UCS and CBR values were improved, and the optimum values were observed at 0.6% arecanut coir dosage. The addition of cement has resulted in a change in silica, alumina, and calcium oxide contents, thereby contributing to the formation of hydration products. The samples with 1% coir and cement have completed 12 wet–dry cycles, but the weight loss observed was >14%. All the specimens showed low soil loss under freeze–thaw cycles. The performance of cured specimens under fatigue loading was satisfactory. Since the specimens could not pass wet–dry durability criteria, they can be considered for modified subgrade. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Soil Stabilization Using Spent Coffee Residue with Geopolymerization Technique(Springer Science and Business Media Deutschland GmbH, 2024) Lalfakzual; I Talkeri, H.T.; Raghuram, K.C.; Chiranjeevi, K.Spent coffee residue contains a significant amount of biodegradable material and is extremely organic. This study aims to assess the feasibility of blending the soil with spent coffee residue and industrial by-products such as fly ash and slag through a sustainable approach using the geopolymerization technique. Geopolymerization was induced using fly ash (FA) and slag as precursors with sodium hydroxide and sodium silicate as alkaline activators. Modified compaction was investigated to determine the optimum moisture content and bearing strength of the mixes produced. The Taguchi's L-9 orthogonal array served as the foundation for the formulation of all nine geopolymer mixes created herein. In an initial calibration phase, the durability and unconfined compressive strength (UCS) characteristics of a set of nine mixes were utilized for performance evaluation. On the basis of these findings, strength and durability prediction equations were developed. In the prediction phase, the accuracy of the developed model is evaluated with actual test results from trials on the nine mixes. Partial replacement of slag by 20 and 30% with the desired sodium oxide content range between 3 and 5% complied with the standard for subgrade material. Test results indicate stabilized coffee residue might be used as subgrade material rather than being dumped in landfills. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Prediction of uniaxial compressive strength, tensile strength and porosity of sedimentary rocks using sound level produced during rotary drilling(2011) Rajesh Kumar, B.R.; Vardhan, H.; Govindaraj, M.The main purpose of the study is to develop a general prediction model and to investigate the relationships between sound level produced during drilling and physical properties such as uniaxial compressive strength, tensile strength and percentage porosity of sedimentary rocks. The results were evaluated using the multiple regression analysis taking into account the interaction effects of various predictor variables. Predictor variables selected for the multiple regression model are drill bit diameter, drill bit speed, penetration rate and equivalent sound level produced during rotary drilling (Leq). The constructed models were checked using various prediction performance indices. Consequently, it is possible to say that the constructed models can be used for practical purposes. © Springer-Verlag 2011.Item Effect of Electrolyte Lignin and Fly Ash in Stabilizing Black Cotton Soil(Springer US, 2015) Lekha, B.M.; Goutham, G.; Ravi Shankar, A.U.Subgrade is one of the important layers of any pavement. It must be able to support loads transmitted from pavement structure without excessive deformation under adverse climatic and traffic conditions. In this investigation, laboratory studies were carried out to evaluate the influence of a commercial electrolyte lignin stabilizer (ELS), fly ash (FA) and a combination of both, on black cotton (BC) soil procured from North Karnataka region in India. Basic geotechnical and engineering properties like unconfined compressive strength (UCS), California bearing ratio (CBR), etc. were determined for both untreated and treated soil. Dynamic repeated load test was conducted to examine the fatigue behaviour of the soil. Durability of the soil was checked by wet-dry (WD) and freeze-thaw (FT) cycle tests, and swelling properties by free swell index test. From the studies, it was observed that consistency limits, dry density, UCS and CBR values were improved for treated soil, with curing periods of 1, 7 and 28 days. Weight loss in FT test was less than 14 % for 12 cycles, which ensures that the stabilized soil has become durable. But none of the samples were observed to be withstanding above five cycles in wet-dry test. Soil stabilized with ELS and FA showed better results compared to soil with only ELS. Swelling was reduced to a great extent with 28 days curing period for the former one. From the experimental results, it can be concluded that this chemical can be used as a stabilizer for existing BC soil in site to enhance its subgrade strength. © 2015, Springer New York.