Browsing by Author "Sharath, B.P."

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COMPARISON OF MULTI CRITERION DECISION MAKING APPROACHES (MCDM) ON PRODUCED FLY ASH BASED PELLETIZED GEOPOLYMER COARSE AGGREGATES INTEGRATED WITH IRON ORE TAILINGS
(Associated Cement Companies Ltd., 2023) Sharath, B.P.; Akhilesh Kumar, A.R.; Das, B.B.
This research paper explores the implementation of multi-criteria decision-making approaches (MCDM) in the produced fly ash (FA) based pelletized geopolymer coarse aggregates integrated with iron ore tailings (IOT). Despite the fact that many techniques are available to aid the decision-making process, the decision makers (here the authors) are forced to go through the laborious task of selecting the appropriate MCDM method. It is because of the fact that each approach/method results in the attainment of different outcomes when applied to such specific scenario (in this case, the produced FA-based aggregates integrated with IOT). This research paper assesses three varied MCDM approaches, that are grey relation analysis (GRA), technique for order preference by similarity to ideal solution (TOPSIS) and desirability function approach (DFA), for the sixteen mixes involved in the production of FA-based aggregates integrated with IOT. These sixteen mixes were designed by taking into consideration of four experimental parameters that were Na2O and water content dosages, blend proportion of IOT and FA and SiO2/Na2O ratio, with the aid of Taguchi’s experimental methodology. The characteristics of the produced FA-based aggregates like aggregate impact value, aggregate crushing value, individual crushing strength of aggregates and water absorption served as inputs in the implementation of MCDM approaches on the produced FA-based aggregates integrated with IOT. The concluding remarks obtained by the implemented MCDM approaches proved to be effective in understanding the order of influence of experimental parameters taken under consideration for producing FA-based aggregates and among all, GRA stood as a relatively better approach in comparison with the other two approaches. © 2023, Associated Cement Companies Ltd.. All rights reserved.
Engineering Properties of Heavyweight Concreteâ€”A Review
(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Sharath, B.P.; Das, B.B.
Heavyweight concrete which differs from normal weight concrete by having a higher density and special compositions to improve its attenuation properties, the density and cost of the material are really important in order to absorb gamma rays. If the main aim of developing heavyweight concrete is focussed to attenuate neutrons, then the material with less atomic weight should be embodied in the concrete mix which can in turn produce hydrogen. It is used in counterweights of bascule and lift bridges, but its general application includes in radiation shielding structures, offshore, ballasting of pipelines etc. The evolution of nuclear power into peaceful applications has given rise to an expanding use of heavy weight concrete in construction industries nowadays. Heavyweight concrete employs bulky conventional aggregates such as barites or magnetite or artificial aggregates such as Fe ore or Pb shots. This paper states a review on impact on engineering properties of Heavyweight concrete such as compressive, split tensile and flexural strength with different heavyweight aggregates as per the investigations conducted by researchers. Â© 2021, Springer Nature Singapore Pte Ltd.
Influence of Geopolymerization Factors on Sustainable Production of Pelletized Fly Ash-Based Aggregates Admixed with Bentonite, Lime, and GGBS
(American Society of Civil Engineers (ASCE), 2023) Sharath, B.P.; Snehal, K.; Das, B.B.; Barbhuiya, S.
This experimental research investigates the influence of geopolymerization factors such as Na2O dosages, water and mineral admixture [bentonite (BT), burnt lime (BL), and ground granulated blast furnace slag (GGBS)] on physiomechanical properties of the pelletized fly ash (FA)-based aggregates. Taguchi's L9 orthogonal array was adopted to design the mixing ratios for three kinds of fly ash-based aggregates (in the combinations of FA-BT, FA-BL, and FA-GGBS). The degree of geopolymerization of the produced aggregates was characterized using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and a scanning electron microscope (SEM). Most influential response indices in the production of pelletized aggregates were identified using gray relational analysis. The physiomechanical characteristics of the fly-ash aggregates were significantly improved by admixing BL than that of GGBS and BT. However, pelletization efficiency was seen to be superior for GGBS-substituted fly-ash aggregates. The quantified amount of hydration products, i.e., sodium alumino-silicate hydrate (N-A-S-H)/calcium alumino-silicate hydrate (C-A-S-H) for fly ash-based aggregates intensified on increasing Na2O and mineral admixture dosages. The results strongly suggest the existence of a linear relationship between the quantified amount of N-A-S-H/C-A-S-H and individual pellet strength of produced aggregate. The FTIR spectrum showed strong and broadened bands of Si-O terminal for all types of aggregates, representing the conversion of unreacted minerals to chains of aluminosilicate gel (geopolymerized hydration product). Further, it can also be inferred from gray relational analysis that among all other factors, Na2O content significantly impacted the engineering properties of produced fly ash-based aggregates. © 2023 American Society of Civil Engineers.
Influence of Integration of Iron Ore Tailings on the Physio-mechanical and Microstructure Properties of Fly Ash Based Coarse Aggregates
(ASTM International, 2023) Sharath, B.P.; Nikunj, P.; Das, B.B.
The goal of this experimental study is to produce fly ash (FA)-based coarse aggregates by adding iron ore tailings (IOT) to the FA-based precursor as an additional mix component. The involvement of different types of binders - influential factors of both pelletization and geopolymerization that govern the production of FA-based coarse aggregates - was experimentally designed by adopting Taguchi's experimental design. An evaluation was conducted utilizing response indexes at three curing periods to study the accumulation of all the influencing factors in the production process as well as on the engineering features of IOT admixed FA-based coarse aggregates. Aggregate impact and crushing values, individual pellet strength (IPS), and specific gravity and water absorption values were measured. According to experimental findings, IOT addition considerably affects the engineering characteristics of FA-based coarse aggregates. The heat resistance of the produced aggregates was found to be improved by the presence of different sodium oxide dosages and blending ratios (IOT:FA) based on analysis through scanning electron microscopy and thermogravimetric differential thermal analysis. The role of IOT in associative formation of calcium silicate hydrate is demonstrated by increasing calcium hydroxide, which supports increasing IPS values of produced aggregates. From the 1st to the 200th day of curing age, Fourier-transform infrared spectroscopy studies between the best- and worst-performing mixes showed two things: first, the emergence of new peaks with time, and second, the observation of major bands shifting to lower and higher wavenumbers, which was found to be directly correlated to the performance of the aggregates. © 2023 ASTM International. All rights reserved.
Pelletisation factors on the production of fly-ash aggregates and its performance in concrete
(ICE Publishing, 2023) Shivaprasad, K.N.; Das, B.B.; Sharath, B.P.
This research study investigates the factors associated with pelletisation in the production of fly-ash aggregates and its performance in concrete. To investigate this influence, experiments were carried out in different stages to explore the effect of factors responsible for pelletisation, which were designed through Taguchi’s experimental design. Additionally, the influence of each parameter on the engineering properties of the produced aggregates was determined using Grey relational analysis. Further, considering the optimised pelletisation factors of the laboratory-scale studies and with the help of an industrial-scale pelletiser, mass production of fly-ash aggregates was carried out and characterised for their engineering properties. The test results indicate that these aggregates are mainly governed by water content followed by the angle and speed of pelletizing disc. It is observed from the results that the engineering properties of aggregates produced on an industrial scale are found to be better than sintered aggregates and also comparable with that of natural aggregates except for water absorption. The properties of concrete produced with fly-ash aggregates, light weight sintered aggregates and natural aggregates were also studied. The results showed that properties of concrete produced with fly-ash aggregates are in good correlation with those of conventional concrete produced with natural aggregates. © 2023 ICE Publishing. All rights reserved.
Production of Artificial Aggregates Using Industrial By-Products Admixed with Mine Tailingsâ€”A Sustainable Solution
(Springer Science and Business Media Deutschland GmbH, 2021) Sharath, B.P.; Das, B.B.
This experimental cum research exploration is focused on the production of artificial aggregates with an adoption of pelletization technique. The influential factors for ascertaining the efficiency of the production process are nature of binding agent, required moisture content, process duration and dosage of alkali binder. Aggregates were produced in various combinations including the industrial by-products replaced partially by mine tailings with the addition of some percentages of lime. These produced aggregates were analysed for their engineering properties. It was observed that with the utilization of these mine tailings in this production of artificial aggregates have given an enhancement in the basic characteristic properties of the produced aggregates which are nearly comparable to that of natural aggregates. Â© 2021, Springer Nature Singapore Pte Ltd.
Research on Setting Time, Compressive Strength and Microstructure of Fly Ash-Based Geopolymer Mixture Containing Slag
(Springer Science and Business Media Deutschland GmbH, 2023) Prasanna, K.M.; Sharath, B.P.; Choukade, H.; Shivaprasad, K.N.; Das, B.B.; Mahesh, G.
This study focusses on upgrading the fresh and hardened properties of fly ash-based geopolymer mix samples such as initial and final setting time, flow table test and compressive strength with the substitution of ground granulated blast furnace slag at varied percentage levels and with different alkali binder ratios. Substitution of slag in geopolymer mix samples is important so as to achieve fast setting characteristics in the product. For studying these effects on the microstructure of the product, scanning electron microscopy (SEM) with energy dispersive spectroscopy and Fourier transform infrared spectroscopy were conducted. The experimental outcomes stated that an increase in slag substitution has decreased the setting time and increased the compressive strength of geopolymer mix samples. SEM images have revealed the occurrence of a dense matrix with the slag substitution. FTIR results stated that shifting in wavenumbers of characteristic bands to lower numbers for varied slag substitution levels indicates a greater extent of geopolymerization. © 2022, The Author(s), under exclusive licence to Shiraz University.
Some Studies on Sustainable Utilization of Iron Ore Tailing (IOT) as Fine Aggregates in Fly Ash Based Geopolymer Mortar
(2018) Sharath, B.P.; Shivaprasad, K.N.; Athikkal, M.M.; Das, B.B.
This study presents the sustainable utilization potential of Iron Ore Tailings (IOT) as a replacement material against natural fine aggregates in the preparation of fly ash based geopolymer mortar. Low calcium fly ash is used as the source material and a mixture of sodium hydroxide and sodium silicate is used as the alkaline activator in the mix. Systematic studies such as setting times and compressive strength of the various mixes with different alkali binder ratio's were investigated in detail. It is to be noted that setting times of the mixes were found to be increasing with the increase in alkali binder ratio (0.4 to 0.8). Alkali binder ratio of 0.6 is found to be the optimum with respect to the compressive strength, irrespective of the type of fine aggregate. Scanning electron microscopy also reveals that microstructure of the fly ash based geopolymer mortar produced had a dense matrix with utilization of the Iron ore tailing. It can be concluded from the study that IOT is found to be a best alternative against the natural sand as a fine aggregate. � 2018 Institute of Physics Publishing. All rights reserved.
Some Studies on Sustainable Utilization of Iron Ore Tailing (IOT) as Fine Aggregates in Fly Ash Based Geopolymer Mortar
(Institute of Physics Publishing helen.craven@iop.org, 2018) Sharath, B.P.; Shivaprasad, K.N.; Athikkal, M.M.; Das, B.B.
This study presents the sustainable utilization potential of Iron Ore Tailings (IOT) as a replacement material against natural fine aggregates in the preparation of fly ash based geopolymer mortar. Low calcium fly ash is used as the source material and a mixture of sodium hydroxide and sodium silicate is used as the alkaline activator in the mix. Systematic studies such as setting times and compressive strength of the various mixes with different alkali binder ratio's were investigated in detail. It is to be noted that setting times of the mixes were found to be increasing with the increase in alkali binder ratio (0.4 to 0.8). Alkali binder ratio of 0.6 is found to be the optimum with respect to the compressive strength, irrespective of the type of fine aggregate. Scanning electron microscopy also reveals that microstructure of the fly ash based geopolymer mortar produced had a dense matrix with utilization of the Iron ore tailing. It can be concluded from the study that IOT is found to be a best alternative against the natural sand as a fine aggregate. Â© 2018 Institute of Physics Publishing. All rights reserved.