Department of Civil Engineering

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Author: search.filters.author.Bhunia, DipenduSubject: search.filters.subject.Civil Engineering

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    Alkali-Activation Potential of Sandstone Wastes with Electric Arc Furnace Slag as Co-additive
    (Springer, 2023-12) Bhunia, Dipendu; Chakraborty, Sayantan
    Electric arc furnace slag (EAF) and sandstone waste (SW) are two of the most abundantly generated industrial wastes whose utilization as precursors and supplementary cementitious materials has not been exhaustively studied. The current research study comprehensively investigates the effects of incorporating varying proportions (0–90%) of re-melted EAF as a co-additive on the engineering properties of elevated (80 °C) and ambient (30 °C) cured alkali-activated SW-based binders. Extensive laboratory tests were conducted to assess the physio-mechanical and durability performance of the resulting alkali-activated materials (AAM). Detailed mineralogical and microstructural characterization of SW, EAF, and alkali-activated samples was carried out using sophisticated analytical techniques. Results advocated that irrespective of the curing temperatures, SW-based AAM showed improved setting behavior, compressive strength, water absorption, and porosity characteristics with the increment of EAF at all substitution levels due to the concomitant development of CASH-CSH-NASH gel phases. Overall, it can be inferred that EAFs as a pozzolanic material successfully augmented the properties of SW-based alkali-activated binders, providing an efficient solution for disposal and negative environmental impacts associated with industrial wastes.
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    Influence of activator ratios and concentration on the physio-mechanical and microstructural characteristics of the geopolymers derived from sandstone processing waste
    (Springer, 2024-03) Bhunia, Dipendu; Lahoti, Mukund; Chakraborty, Sayantan
    Natural stones have been utilized to meet various needs of human civilization since ancient times. The exploitation of any resource is associated with the production of redundant materials called wastes. Sandstone waste (SW) is one such waste obtained during the industrial processing of sandstones. Due to its siliceous composition, extensive yield, and disorganized dumping, noxious conditions related to land and human health are promoted. However, the lack of comprehensive engineering studies, mineralogical analysis, and design methodologies associated with the utilization of sandstone processing wastes restricted their applicability only to fillers or partial substitutes with pozzolans and traditional cement in meager volumes. In the past, limited efforts have been made to utilize SW as a construction entity, particularly for binding purposes. Thus, to enhance the scope of its utilization, a comprehensive investigation has been performed in this research to transform sandstone waste into a novel construction material by geopolymerization. Mix design tailoring and laboratory tests were implemented to understand the effects of sodium hydroxide concentration and sodium silicate to sodium hydroxide ratio on the dissolution and physio-mechanical characteristics of SW-based geopolymers. The activator-to-binder ratio was restricted to 0.4 to obtain pastes with sufficient workability without hindering the properties of the matrix. Besides, a high temperature-curing regime was selected based on SW's crystallographic and reactivity analysis. Subsequently, a total of 48 samples were prepared and tested at the curing age of 28 days. Detailed characterization of SW and SW-based geopolymer samples was performed using optical, X-ray, and infrared spectroscopies aided by electron imaging and thermogravimetric techniques. SW-based geopolymer samples showed compressive strengths in the range of 6-12 MPa, ~2 to 3 times higher than those obtained in previous experimentations. Phase analysis and microstructural examinations confirmed SW's participation in geopolymerization. Overall, it could be advocated that geopolymerization is an innovative approach for solving issues related to the disposal and re-utilization of SW, extending its possible application to the fields of cement mixes, wall tiles, mortars, and masonry as per the commendations of ASTM and ACI committee.
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    Fired clay bricks synergistically valorizing hazardous nickel chrome-plating sludge and fly ash: Performance assessment
    (Elsevier, 2024-04) Singhal, Anupam; Routroy, Srikanta; Bhunia, Dipendu; Lahoti, Mukund
    Nickel Chrome Plating Sludge (NCPS) is a hazardous waste containing 25%-30% nickel and chromium. Previous attempts to immobilize NCPS into fired clay bricks resulted in weakened strength due to porosity and microstructure deterioration. This study introduces co-valorization of NCPS and fly ash in fired clay bricks to address these issues. Factory-scale firing of green bricks, alongside conventional clay bricks, assessed the commercialization potential. The optimal proportion of NCPS, fly ash, and clay was found to be as 12.5:37.5:50.0, respectively. Fly ash addition significantly improved brick properties, causing compressive strength to increase from 3.2 MPa to 11.6 MPa for a NCPS content of 12.5%. Microstructural analysis highlighted fluxing oxides in NCPS, amorphous silica-alumina in fly ash, synergistic ceramic bond formation, enhanced sintering and pore filling during vitrification. The study also demonstrated substantial fuel savings of 40%-50% due to NCPS's high heat of combustion causing internal firing of green bricks. The developed bricks exhibited almost double linear attenuation coefficients, indicating enhanced gamma radiation shielding. Leaching tests confirmed successful heavy metal immobilization. This co-valorization approach not only overcomes previous drawbacks but also offers significant environmental and economic benefits in utilizing NCPS in brick production.
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    Nonlinear analysis of sandwich plate with FG porous core and RD-CNTCFRC face sheets under transverse patch loading
    (Springer, 2022-09) Kumar, Rajesh; Bhunia, Dipendu; Patel, Shuvendu Narayan
    Nonlinear bending analysis of a sandwich plate with randomly distributed carbon nanotube and carbon fiber-reinforced composite (RD-CNTCFRC) face sheets and functionally graded (FG) porous core subjected to transverse patch loading is performed in the present work. The mechanical properties of the hybrid matrix, which is formed after mixing of single-walled carbon nanotubes and polymer epoxy, are estimated using Eshelby–Mori–Tanaka techniques. Subsequently, the rule of mixture technique is employed to compute the mechanical properties of RD-CNTCFRC face sheets. The mechanical properties of a functionally graded porous core are determined considering both the open-cell and closed-cell metal foam. Utilizing the mechanical properties of RD-CNTCFRC face sheets and FG porous core, the effective properties of RD-CNTCFRC porous sandwich plate are estimated. The sandwich plate is modeled based on higher-order shear deformation theory in conjunction with von Kármán geometric nonlinearity, and subsequently minimization of potential energy is employed to obtain the partial differential equations (PDEs). PDEs are solved using Galerkin’s method and reduced to nonlinear algebraic equations (NAEs). Later, these NAEs are solved via Newton–Raphson method to analyze the nonlinear bending behavior of the RD-CNTCFRC porous sandwich plate using various parameters which can help in suitable design of sandwich plates.
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    A Procedure for the Evaluation of Coupling Beam Characteristics of Coupled Shear Walls
    (Asian Journal of Civil Engineering, 2007) Bhunia, Dipendu
    The behavior of coupled shear walls is governed by coupling beams. This paper presents a simple technique for the purpose of design to determine an appropriate level of yield moment capacity for the coupling beams. This technique is checked against nonlinear static pushover analysis performed using DRAIN-3DX for the usual case of symmetric coupled shear walls with different types of coupling beams. The assumption of pinned base in the shear walls with steel coupling beams yields results which agree closely with those of DRAIN-3DX. For the case of fixed base shear walls, the design technique is expected to be conservative
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    Investigation into the Behavior of Coupled Shear Walls
    (Taylor & Francis, 2018-03) Bhunia, Dipendu
    An effective design technique for symmetrical coupled shear walls is presented in this paper. The proposed formulation, including assumptions and steps with mathematical formulation, has been elaborated to arrive at the design technique. An example has been considered to validate the technique with the DRAIN-3DX and SAP non-linear analysis. A parametric study has also been considered to find out the limitations of this technique and suggest remedial action. It is concluded that the proposed design technique can be considered in the design of coupled shear walls under seismic motion.
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    A study on the behaviour of coupled shear walls
    (Korea Science, 2012-06) Bhunia, Dipendu
    An effective design technique for symmetrical coupled shear walls is presented. Proposed formulation including assumptions and steps with mathematical formulation has been elaborated to make the design technique. An example has been considered to validate the technique with the DRAIN-3DX (1993) and SAP V 10.0.5 (2000) nonlinear programs. Parametric study has also been considered to find out the limitations along with remedial action of this technique. On the other hand, nonlinear static analysis is considered to determine the response reduction factor of coupled shear walls. Finally, it has been concluded in this paper that the proposed design technique can be considered to design the coupled shear walls under seismic motion.
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    Investigation of the behavior of conventional reinforced coupling beams
    (Begell House, 2013) Bhunia, Dipendu
    Coupled shear walls consist of two shear walls connected intermittently by beams along the height. The behavior of coupled shear walls is mainly governed by the coupling beams. The coupling beams are designed for ductile inelastic behavior in order to dissipate energy. The base of the shear walls may be designed for elastic or ductile inelastic behavior. The amount of energy dissipation depends on the yield moment capacity and plastic rotation capacity of the coupling beams. In this paper, an analytical model of the coupling beam has been developed to calculate the rotations and moment capacities of coupling beams with conventional reinforcement.
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    A Conceptual Design Approach of Coupled Shear Walls
    (Hindawi Publishing Corporation, 2013) Bhunia, Dipendu
    The growth of population density and shortage of land in urban areas are two major problems for all developing countries including India. In order to mitigate these two problems, the designers resort to high-rise buildings, which are rapidly increasing in number, with various architectural configurations and ingenious use of structural materials. However, earthquakes are the most critical loading condition for all landbased structures locatedinthe seismically active regions. The Indian subcontinent is divided into different seismic zones as indicated by IS 1893 (Part 1) [1], facilitating the designer to provide adequate protection against earthquake. A recent earthquake in India on January 26th, 2001 caused considerable damage to a large number of RCC high-rise buildings (number of storey varies from 4 to 15) and tremendous loss of life. The reasons were (a) most of the buildings had soft and weak ground storey that provided open space for parking, (b) poor quality of concrete in columns, and (c) poor detailing of the structural design (http://www.nicee.org/eqeiitk/ uploads/EQR Bhuj.pdf).
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    Solution of Shear Wall Location in Multi­Storey Building
    (International Journal of Civil and Structural Engineering, 2011) Bhunia, Dipendu; Srivastava, Anshuman
    Shear wall systems are one of the most commonly used lateral­load resisting systems in high­ rise buildings. Shear walls have very high in­plane stiffness and strength, which can be used to simultaneously resist large horizontal loads and support gravity loads, making them quite advantageous in many structural engineering applications. There are lots of literatures available to design and analyse the shear wall. However, the decision about the location of shear wall in multi­storey building is not much discussed in any literatures. In this paper, therefore, main focus is to determine the solution for shear wall location in multi­storey building based on its both elastic and elasto­plastic behaviours. An earthquake load is calculated and applied to a building of fifteen stories located in zone IV. Elastic and elasto­plastic analyses were performed using both STAAD Pro 2004 and SAP V 10.0.5 (2000) software packages. Shear forces, bending moment and story drift were computed in both the cases and location of shear wall was established based upon the above computations