Faculty Publications

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    Partial replacement of steel slag aggregates in concrete as fine aggregates (induction blast furnace slag)
    (Springer, 2019) Sundaramoorthi, S.; Hemalatha, T.; C, C.
    In this study, an attempt has been made to investigate the effect of partial replacement of conventional river sand with steel slag aggregate. The replacement of river sand by slag aggregate provides dual advantage of reducing disposal problems in steel industries and conserving the natural resources. In this study, slag aggregate originated from induction blast furnace has been used. The physical and chemical properties of slag aggregate evidenced the feasibility of using this material as a substitute for river sand. Total of three mixes made with Ordinary Portland Cement (OPC), cement replaced with fly ash and river sand replaced with slag aggregate have been considered for this study. The mix is designed for M40 grade. First mix (Control mix 0M0) made of OPC as a binder and 100% river sand, second mix (0M50) made of OPC and 50% slag aggregate and third mix (25M50) made of 25% OPC replaced by fly ash and 50% river sand replaced by slag aggregate. Mechanical and durability properties of all the three concretes are studied. It is found that the strength results of 0M0 and 0M50 are comparable indicating the suitability of using slag aggregate as an alternative for river sand. However, the third mix with fly ash replacement in binder showed reduced strength in comparison with control concrete. Hence, it is concluded that when slag aggregate is used as a partial replacement for river sand (50%), it is advisable to use OPC than the Pozzolanic Portland Cement (PPC). © Springer Nature Singapore Pte Ltd. 2019.
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    Durability studies of polypropylene fibre reinforced concrete
    (Springer, 2019) Srikumar, R.; Das, B.B.; Goudar, S.K.
    A research programme was initiated to understand the durability of polypropylene fibre reinforced concrete (PFRC). PFRC was prepared with varying dosages of polypropylene fibre. Dosages used were 0.5–1.5% of cement content (by weight) with an interval of 0.5% and was added as a cement replacement to concrete mix. Durability studies were carried out by exposing the 28 days cured cubical specimens into marine environment having different pH levels (1, 4, 7, 10 and 13). The varying pH levels represent the pH of industrial effluents. The marine environment was simulated in the laboratory by adding 3.5% NaCl to the tap water. The specimens were exposed for the durations of 60 and 90 days. The resistance of concrete to marine environment was measured through compressive strength retention and ultimate bond strength retention. Scanning Electron Microscopy (SEM) studies were also carried out to understand the fibre dispersion. Test results show that compressive and bond strength increases with increase in pH and decreases with increase in immersion duration. Concrete with 0.5 and 1% fibre content are more desirable and have given higher residual compressive and residual bond strength when compared to concrete with 1.5% fibre content. © Springer Nature Singapore Pte Ltd. 2019.
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    Durability studies on glass fiber reinforced concrete
    (Springer, 2019) George, R.M.; Das, B.B.; Goudar, S.K.
    In the present experimental study, glass fibers were used in varying dosages of 0.5, 1.0, and 1.5% of cement content (by weight) as partial cement replacement to cement in concrete mix. The effect of different dosage of glass fibers on the bond strength between steel and concrete in reinforced concrete was investigated. As a part of durability study, the combined effect of marine environment and varying levels of pH on the ultimate bond strength retention and compressive strength retention of glass fiber reinforced concrete was also studied. Durability studies were carried out by exposing the 28-day cured cubical specimens into marine environment having different pH levels (1, 4, 7, 10 and 13). The salt solution was simulated in the laboratory by adding 3.5% NaCl to the tap water. Calculated amount of sulphuric acid was added to salt solution to maintain pH of 1 and 4 in marine environment. Similarly, calculated amount of sodium hydroxide was added to salt solution to maintain pH of 10 and 13 in marine environment. The specimens were exposed to aggressive environment for a period of 60 and 90 days. As the fiber dosage increased the workability reduced, and 1.5% fiber dosage had the least slump value. The addition of glass fibers had very minimal influence on compressive strength of glass fiber reinforced concrete. The ultimate bond strength of concrete increased due to the addition of glass fibers. The increase in ultimate bond strength was confirmed through SEM images which shows proper bonding between cement paste and glass fibers. As for as the exposure studies are concerned, 1.0% fiber dosage of glass fiber reinforced concrete had shown better compressive strength and ultimate bond strength retention compared to 0.5 and 1.5% fiber dosage. The pH of the marine environment has a decisive influence on the compressive strength retention and bond strength retention. Exposure to marine environment with pH 1 suffered severe loss in compressive strength and ultimate bond strength with very low strength retention values. However, exposure to marine environment with pH 10 and 13 had minimal strength losses with higher values of compressive strength and ultimate bond strength retention. Increase in exposure period to aggressive media leads to decrease in compressive strength and ultimate bond strength, but the strength retention values for glass fiber reinforced concrete were comparatively better compared to control concrete. © Springer Nature Singapore Pte Ltd. 2019.
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    Strength Behavior of Rammed Earth Stabilized with Metakaolin
    (Springer, 2020) Thiviya, S.K.; Krishnan, A.G.; Kalathuru, M.; Sharma, A.K.; Kolathayar, S.
    Rammed earth is an ancient construction technique practiced in India and in other parts of the world. The ancient traditional technique was of the un-stabilized method but incorporating suitable stabilizing materials will improve the strength of rammed earth construction. The main objective of the present study is to assess the behavior of the rammed earth with metakaolin. The suitability of the soil was tested based on sieve analysis and followed by mini compaction tests; optimum moisture content for the rammed earth construction for the selected soil was fixed for different proportions of binders with the soil. From the compaction results, the binder content was fixed for stabilization of rammed earth. The unconfined compressive strength of the sample was found for the samples at 7, 14, 28 days of curing, and microstructural studies of the samples were performed. The compression strength of rammed earth cubes was tested and also the durability of the cubes was determined by the spray erosion test. © 2020, Springer Nature Singapore Pte Ltd.
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    Performance of concrete structures in the marine environment of Karnataka, India
    (2003) Devadas Bhat, S.; Samaga, B.R.
    Well-made concrete often survives better than might otherwise be expected, simply because of its impermeability and its ability to withstand the ingress of corrosive materials. The less the surplus voids the greater is the resistance to deterioration. Corrosion of steel is a multibillion-dollar problem worldwide. However, there are many structures, which show early deterioration, namely those exposed to aggressive environments. In the past and even at present times, too much emphasis is placed on concrete compressive strength rather than on environmental factors, which are known to affect concrete durability. This is one of the main reasons for serious deterioration of concrete structures that is prevalent today. The long-term behaviour of concrete structures has shown that their main cause of distress is reinforcement corrosion. One of the most aggressive exposure conditions for concrete is the marine environment In these condition chloride penetration and chloride induced reinforcement corrosion rates can be very high, often leading to a reduced service life. This paper describes a series of case studies of different types of concrete structures, subjected to marine environment in the West-Coast of Karnataka (INDIA), that have suffered extensive deterioration due to corrosion.
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    Performance Evaluation of Fly-ash based Self-compacting geopolymer concrete mixes
    (Institute of Physics Publishing helen.craven@iop.org, 2019) Manjunath, R.; Ranganath, R.V.
    In this paper, an attempt has been made to develop Fly ash based self- compacting geopolymer concrete mixes with varying volume of pastes using conventionally available river sand as fine aggregate and crushed granite chips as coarse aggregate. These mixes were developed usingFly ash as the only major source material in the production of SCC mixes. Different amounts of Sodium silicate solutions, with specified amounts of Sodium Hydroxide flakes dissolved in them, are used as alkaline solutions. The total of four mixes were developed with varying volume of pastes in the range of 0.40 - 0.52 (within an interval of 0.04). These mixes were evaluated for their flow ability characteristics as per the relevant EFNARC guidelines. Further the mixes were evaluated for their mechanical properties in terms of compressive strength, splitting tensile strength and water absorption characteristics. Durability tests by means of subjecting to acidic and sulphate environments, along with their resistances to sustained elevated temperatures for a sustained period of 2 hours upto 800° C were carried out for all these mixes. The test results indicate better flow ability characteristics, along with their mechanical and durability properties. © 2019 IOP Publishing Ltd. All rights reserved.
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    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.; Avinash
    The 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.
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    Predicting the Service Life of Reinforced Concrete by Incorporating the Experimentally Determined Properties of Steel–Concrete Interface and Corrosion
    (Springer Science and Business Media Deutschland GmbH, 2021) Sumukh, E.P.; Goudar, S.K.; Das, B.B.
    Service life of a reinforced concrete structure depends on its durability in aggressive exposure conditions. In the case of reinforced concrete structures, the phenomenon that directly affects its durability is corrosion of rebar, which has direct influence on the residual service life. Corrosion in reinforced concrete basically initiates at its weakest zone called steel–concrete interface due to its porous nature. The extent of this porous zone is being represented in terms of Porous zone thickness which has been extensively reported by various researchers. This porous zone thickness is one of the key influencing factors in the prediction of residual service life of the reinforced concrete structure. Several mathematical models were proposed by various researchers to estimate the time required for cover cracking of concrete due to rebar corrosion by assuming different values of porous zone thickness (PZT) without any systematic experimental investigation. Assuming a steady value of PZT for all kinds of concrete without any practical justification will misinterpret the predicted residual service life. In the present work, an effort has been made to evaluate an existing analytical model to predict the time to concrete cover cracking by incorporating the experimentally obtained and published data on porous zone thickness. It was found that the porous zone thickness and rate of corrosion have a major role in evaluating the residual service life of reinforced concrete structures. © 2021, Springer Nature Singapore Pte Ltd.
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    Influence of Incorporating Phase Change Materials on Cementitious System—A Review
    (Springer Science and Business Media Deutschland GmbH, 2021) Snehal, K.; Das, B.B.
    Phase change materials (PCMs) are gaining more attention in achieving the sustainability and are being widely adopted as a green building material because of their exclusive ability to store latent heat of thermal energy. PCMs have a capacity to minimize the energy loads and to provide thermal comforts in building infrastructures by its iterative cycle of absorbing and releasing the heat energy. The potential need for manipulating the heating and cooling effect in buildings is significantly increasing especially in temperature fluctuating and varied climatic regions. It is for this one of the significant reasons, PCMs are getting pronounced interest by the research fraternity in the development of a thermally effective PCM-based construction material. In this paper, attempts were made to compile the data reported by the previous researchers on the influence of incorporating PCMs in the engineering properties of cementitious system such as slump, compressive strength, flexural strength, density, porosity, water absorption, shrinkage, durability, heat of hydration, specific heat capacity and thermal conductivity. This paper also discusses the most favorable content of PCM addition and effective methods of incorporating PCMs in the cementitious system. © 2021, Springer Nature Singapore Pte Ltd.
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    Impact of Phase Change Materials on the Durability Properties of Cementitious Composites—A Review
    (Springer Science and Business Media Deutschland GmbH, 2023) Vismaya, K.; Snehal, K.; Das, B.B.
    Phase change materials (PCMs) are the novel thermal storage materials which have an ability to engross and dispel heat during the process of phase transition from solid to liquid and vice versa. Utilization of PCMs in cementitious composites has gained a lot of attention from the research fraternity to minimize the energy loadings used for space conditioning and heating in building. Impact of PCM’s presence in cementitious composites on the durability parameters is the need for its better usage. This paper gives the state of review on the influence of inclusion of phase change materials in the cementitious system on its various durability aspects. Durability properties such as porosity, water absorption, shrinkage, chloride ingression, and chemical attacks are compiled in this article. It is stated that the integration of PCM in cement composites enhances the porosity of cementitious system. Major hindrance described by the researchers is the interruption of hydration activity of cementitious system by the addition of PCM. Literature also signified that the micro/nano encapsulates PCMs and the use of highly reactive Pozzolans such as silica fume or nano-silica in conjunction with PCMs has the ability to lock up the limitations of PCMs. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.