Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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    Ultra high performance concrete-sustainable solution for the next generation infrastructure
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2017) Gowda, H.; Das, B.B.
    Sustainability of the infrastructure has become a major challenge for the construction industry. The serviceable life of the constructed facilities in the developed countries of the world is reducing with the major changes occurring in the climate, where the pollution level is rising everyday by various manmade and natural processes. For a developing country like India, in this situation, there is a need for the adoption of a durable material for construction of nation's infrastructure facilities such as buildings, roads, ports, railways, and bridges. These facilities should be durable, however, their cost of construction and the life cycle maintenance need to be as low as possible. Considering this into account, an extensive review of research reported by several researchers on various engineering properties of ultra-high performance concrete (UHPC) is discussed in this manuscript. This manuscript holds information on the recent breakthrough by several researchers pertaining to UHPC. In brief, this manuscript mainly deals with the invention and background of UHPC which includes how UHPC is different than normal concrete and high performance concrete (HPC) with respect to its micro structure and its composition. Also, an elaborate description of all the mechanical properties of UHPC is being discussed here.
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    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. © 2018 Institute of Physics Publishing. All rights reserved.
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    Effect of Duration of Heat Curing on the Artificially Produced Fly Ash Aggregates
    (Institute of Physics Publishing helen.craven@iop.org, 2018) Shivaprasad, K.N.; Das, B.B.
    This paper presents the results of an experimental investigation on the production of artificial fly ash aggregates through the process of pelletization. The alkaline solutions like sodium silicate and sodium hydroxide was used to activate the fly ash. The alkaline solution contains 4.5% of Na2O, Si2O/Na2O ratio of 0.3 and 20% of water content with respect to mass of fly ash were used as binder in the production of fly ash geopolymer aggregates. The experiments were conducted by varying with different parameters. Curing of artificial fly ash aggregates was done with ambient temperature and heat curing (60 to 80 °C). Six levels of duration of heat curing were considered for this study. The optimum temperature and duration of curing is essential in geopolymerization reaction to achieve good characteristics of the produced aggregates. Grey relation analysis was performed to identify the effect of heat curing. Test results and grey relation analysis shows that the characteristics of the artificial produced fly ash aggregates has significantly improved with increase in temperature and duration of oven curing. © 2018 Institute of Physics Publishing. All rights reserved.
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    A Review on the Properties of Steel-Concrete Interface and Characterization Methods
    (Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Sumukh, E.P.; Goudar, S.K.; Das, B.B.
    The Steel-Concrete interface (SCI) is usually regarded as the weakest region, which influences both mechanical properties and durability of reinforced concrete structures. Several researchers have well explored and defined the importance of SCI on the service life of the reinforced concrete structures as it directly affects the durability. The primary objective of this paper is to report and compare a variety of published findings and microstructural analysis on the SCI in one place which appears in reinforced concrete. The information available on the occurrence, formation, properties, various characterizing and analysing techniques of SCI are reviewed for a better understanding of microstructural properties of SCI on the hardened and durability properties of reinforced concrete. It was found that the SCI exhibits significant spatial inhomogeneity along and around as well as perpendicular to the reinforcing steel. Significant factors like quantification of porosity, porous zone thickness and actions that affect the properties of SCI like wall effect, bleeding, settlement and segregation of fresh concrete which were favourable to both initiation and propagation of corrosion are described in this paper. The influence of w/c ratio, hydration age, steel orientation and mineral admixtures on the distribution profiles of hydration products and Engineering properties of SCI is also discussed. © 2021, Springer Nature Singapore Pte Ltd.
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    Influence of Fineness of Mineral Admixtures on the Degree of Atmospheric Mineral Carbonation
    (Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Farsana, C.; Das, B.B.; Snehal, K.
    Global carbon dioxide concentration is rising at the rate of 2 ppm every year, which had led to the demand of sustainable development. In construction industry, manufacturing of cement is the main source of global anthropogenic carbon dioxide emissions. Carbon capture and storage is a recent technology which had helped to sequester carbon dioxide from atmosphere and thus helps in reducing the greenhouse effect to a certain extent. This study mainly focuses on the atmospheric mineral carbonation of mineral admixtures like fly ash (FA), ground granulated blast furnace slag (GGBS), and silica fume (SF), which are the industrial by-products and are being treated as waste. This study also focuses on the effect of fineness of different mineral admixtures on the degree of atmospheric mineral carbonation. Fly ash with three different levels of fineness (FA, FA I, and FA II), GGBS with three different levels of fineness (GGBS, GGBS I, and GGBS II), and silica fume were mixed with activators like lime and gypsum and were left for atmospheric mineral carbonation. Mineralogical characterisations were done using X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM). Degree of carbonation of the samples was analyzed and calculated using the TGA results. From the comparative analysis of all the samples, it was found that GGBS II had highest degree of carbonation. It was also observed that calcium-based compounds like calcite, aragonite, vaterite, calcite magnesium syn, gismondine, waikarite, calcium silicate hydrate, diopside, calcium sulfate, and portlandite were formed in the samples after 45 and 90 days of atmospheric mineral carbonation. However, it was observed that with increasing levels of fineness of mineral admixtures, there was no significant change in the degree of atmospheric mineral carbonation. © 2021, Springer Nature Singapore Pte Ltd.
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    Experimental Setup for Thermal Performance Study of Phase Change Material Admixed Cement Composites—A Review
    (Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Snehal, K.; Das, B.B.
    Phase change material (PCM) is a prospective material with a caliber to store thermal energy. The hasty development in the modern world and lavish life style amplified the energy demand. Building and infrastructure are the leading energy and material consumers over the globe. Conservation of building energy associated to heating and cooling is made possible by embedding PCM in construction materials (like concrete) which has a great potential to improve the thermal comfort of the residents. The concrete coupled with PCMs has a tendency to improve the thermophysical properties like heat capacity/thermal mass and thermal insulating property besides with an ability to save energy for the development of sustainable built environment. There are so many techniques and experimental setups used by the researchers to analyze the thermal performance of PCM-admixed cementitious systems. In line to this, an attempt has been made to review the different experimental setup used by various researchers to study the thermal facets (heat capacity, thermal cycle, thermal conductivity, etc.) of PCM-doped cementitious systems. © 2021, Springer Nature Singapore Pte Ltd.
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    Engineering Properties of Heavyweight Concrete—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. © 2021, Springer Nature Singapore Pte Ltd.
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    Productivity Analysis of Shuttering Works for Sewage Treatment Plant
    (Springer Science and Business Media Deutschland GmbH, 2021) Pandey, A.; Chaudhary, P.K.; Das, B.B.
    Formwork is considered as important element of construction projects like in traditional reinforced concrete infrastructure projects. It is labor-intensive work that requires highly skilled workers such as carpenters, bar benders, etc., to execute the work more accurately and efficiently. In view of the fact that it is difficult to find high-skilled workers for formwork process and hence it is important to find the ways or methods of formwork construction that is less labor dependent or in other words methods that are highly productive with minimum number of workers. The quality of formwork exerts a direct influence on the surface of concrete and on its dimensions. Since reinforced concrete work is involved in majority of the buildings, the level of workmanship of the construction project can be identified by seeing the quality of formwork. In order to improve the productivity of the formwork process and its quality then it is necessary to improve its working methodology by identifying the bottlenecks using scientific management. And as we very well know that money is always the center of discussion in our construction projects. To complete the project within its expected, designed cost of the project is one of the major requirements of the project to become a successful project. That’s why the topic ‘Productivity analysis in shuttering for Sewer Treatment Plant Project’ is a great tool to analyze the shortcomings in the present methodology of formwork erection and to mechanize a highly effective model for formwork and this can be achieved by the productivity analysis. © 2021, Springer Nature Singapore Pte Ltd.
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    Effect of Curing Methods on the Artificial Production of Fly Ash Aggregates
    (Springer Science and Business Media Deutschland GmbH, 2021) Shivaprasad, K.N.; Das, B.B.; Krishnadas, S.
    The experimental investigation, provides the results on the artificially produced fly ash aggregates through the pelletization process, is presented in this paper. NaOH and Na2SiO3 were used as alkali activator as a binder. The composition of alkaline solution is maintained as 5% of Na2O and SiO2/Na2O ratio of 0.3 with respect to weight of fly ash used. The detailed investigation is carried out by varying the water content to identify the optimum dosage of water in the alkaline solution in the fly ash pelletization. Further, different methods of curing were investigated to check for the suitable curing method for the production of fly ash aggregate produced. Optimum water content and suitable curing method will be identified through efficiency of pelletization and aggregate properties. Grey relation analysis is performed on the experimental test results to identify the influence of curing method on the produced aggregates. From these results, it is clearly understood that the curing method has significantly improved produced aggregates. © 2021, Springer Nature Singapore Pte Ltd.
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    Influence of Particle Size of Bottom Ash on Mechanical Properties of M30 Grade Concrete
    (Springer Science and Business Media Deutschland GmbH, 2021) Goudar, S.K.; Das, B.B.
    Thermal power plants produce fly ash and bottom ash as by-products. A total of 70% of by-product from thermal power plants accounts for fly ash and remaining 30% is bottom ash. One of the most common uses of bottom ash at the present scenario is structural fill in its coarser form only, and it is reported that the disposal leads to leaching of heavy metals to the groundwater table. These disposal problems and potential health hazards can be reduced by large usage of bottom ash in construction industry. A larger percentage of usage of the bottom ash in concrete will significantly reduce the potential health hazards and will give solution to disposal problems. With this in view, bottom ash collected from the Udupi thermal power plant was classified into two different levels according to their particle size and replaced against fine aggregates for different replacement levels, in producing M30 grade concrete. The raw bottom ash was coarse and classified as Zone-I after sieve analysis. The classification of bottom ash according to the particle size was carried out into different zones such as Zone-II and Zone-III, according to the specifications from IS 383–1970. The attainment of required compressive strength is directly correlated to particle size of bottom ash. Results show 47% reduction in compressive strength of concrete when raw bottom ash was (Zone-I) was replaced by 50% in place of natural river sand (NRS). A little effort in grading the bottom ash and converting coarser raw bottom ash from Zone-I to finer Zone-II bottom ash has proved beneficial in improving the compressive strength of concrete. It was observed that lower specific gravity of bottom ash directly influences density of concrete, which intern has adverse effect on compressive strength. The bottom graded as Zone-II can be replaced to NRS by 15–20%, with little compromise in compressive strength. Through value addition of 5% extra cement content, there is a possibility to increase the replacement level of Zone-II bottom ash to 30% with similar compressive strength as that of control concrete. Through cost analysis, it was found that 30% replacement of Zone-II bottom ash in place of NRS with 5% extra cement content as value addition was found to be economical. © 2021, Springer Nature Singapore Pte Ltd.