Faculty Publications
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Item A Comprehensive Review on the Use of Wastewater in the Manufacturing of Concrete: Fostering Sustainability through Recycling(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Maddikeari, M.; Das, B.B.; Tangadagi, R.B.; Roy, S.; Priyanka, P.B.; Ramachandra, M.L.The primary aim of this review article is to find the influence of wastewater and its characteristics on recycling as an alternative to potable water for concrete preparation. On the other hand, scarcity, and the demand for freshwater for drinking are also increasing day by day around the globe. About a billion tons of freshwater is consumed daily for concrete preparation for various operations such as mixing and curing, to name a few. The rapid development of certain industries such as textile, casting, stone cutting, and concrete production has caused the water supply to be severely affected. Recycling wastewater in concrete offers various potential benefits like resource conservation, environmental protection, cost savings, and enhanced sustainability. This article reviews the effect of various types of wastewater on various physical and chemical properties of wastewater, rheological characteristics, strength, durability, and microstructure properties of concrete. It also explores the potential effects of decomposing agents on enhancing concrete properties. Currently, limited research is available on the use of various types of wastewater in concrete. Hence, there is a need to develop various methods and procedures to ensure that the utilization of wastewater and treated wastewater is carried out in the production of concrete in a sustainable manner. Although wastewater can reduce the workability of fresh concrete, it can also increase its strength and long-term performance of concrete. The use of various types of wastewater, such as reclaimed water and tertiary-treated wastewater, was found to be superior compared to those using industrial- or secondary-treated wastewater. Researchers around the globe agree that wastewater can cause various detrimental effects on the mechanical and physical properties of concrete, but the reductions were not significant. To overcome limited scientific contributions, this article reviews all the available methods of using various types of wastewater to make concrete economically and environmentally friendly. This research also addresses possible challenges with respect to the demand for freshwater and the water crisis. © 2024 by the authors.Item Studies on concrete cylinders subjected to elevated temperatures(2010) Babu Narayan, K.S.; Anil Kumar, G.; Chandrakala, C.; Shashikumar, H.M.; Venkataramana, K.; Yaragal, S.C.; Chinnagiri Gowda, H.C.; Reddy, G.R.; Sharma, A.Concrete is a poor conductor of heat, but can suffer considerable damage when exposed to fire. Concrete in structures is likely to be exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. Unraveling the heating history of concrete is important to forensic research or to determine whether a fire exposed concrete structures and its components are still structurally sound or not. Assessment of fire damage concrete structures usually starts with visual observation of color change, cracking and spalling. On heating, a change in color from normal to pink is often observed and this is useful since it coincides with the onset of significant loss of concrete strength. This work reports the characteristics of concrete at elevated temperatures. Popular normal strength grades (M20, M25, M30, M35, M40 and M45) produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm diameter and 300mm height cylinders) to obtain more meaningful and realistic data. In the preliminary phase 150 mm diameter and 300mm height cylinders were cast, cured and tested by destructive method for gathering data on strength characteristics. Later these test samples were subjected to elevated temperatures ranging from 100°C to 800°C, in steps of 100°C with a retention period of 2 hours. After exposure, weight losses were determined and then again destructive tests were conducted to estimate the residual split tensile strength. Test results indicated that weight and strength significantly reduces with an increase in temperature. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Studies on iron tailings towards usage for paving blocks manufacture(2010) Mangalpady, M.; Sampath Kumar, N.N.Disposal of mill tailings is one of the major problems in mining industry. Investigations are being done all over the world to utilize tailings for useful purposes. The scope of this work is to study the utilization of iron ore tailings in manufacture of concrete paving blocks. Five reference mixes were prepared using cement, jelly dust and baby jelly. Ten paving blocks were prepared from each type of mix, out of which five specimens were cured for 7 days and five were cured for 28 days. By using sand and tailings as fine aggregates, two modified mixes were prepared by replacing jelly dust partly in reference mixes. Similar to reference mix, five mix ratios were made and ten paving blocks were prepared from each type of mixtures. From each set of paving blocks, five specimens were cured for 7 days and the other five specimens were cured for 28 days. Laboratory tests were conducted to assess water absorption and compressive strength of specimens, and graphs were plotted for their comparison among each type of respective mix ratios. In all the comparisons, compressive strength of tailing based mix was higher than the respective reference mix. Similar trend is shown by the graphs plotted for water absorption. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Effect of recuring on compressive strength of thermally deteriorated concrete cubes(2011) Prasanth, S.; Yaragal, S.C.; Babu Narayan, K.S.Concrete is found to undergo degradation when subjected to elevated temperatures during an event such as fire and lose substantial amount of its strength. The loss of strength in concrete is mainly attributed to decomposition of C-S-H and release of chemically bound water, which begins when the exposure temperature exceeds 500°C. When thermally deteriorated concrete is supplied with water there is a substantive gain in strength as a consequence of rehydration of cement that is initiated. This paper presents results of an experimental program carried out to investigate the effect of recuring on strength gain of normal strength concrete specimens subjected to elevated temperatures from 500°C to 800°C, which were subjected to retention time of two hours at the designated temperatures. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Study on the strength parameters of high volume fly ash concrete and geopolymer concrete(2011) Shetty, A.; Anand, V.R.; Hegde, P.Concrete has been the most preferred construction material. It is being increasingly used day by day all over the world due to its versatility, mould ability and high compressive strength. But the large-scale production of cement is causing environmental problems on one hand and the unrestricted depletion of natural resources on the other. So the issue of sustainable development in concrete construction is addressed in this paper through development of concrete mixes by replacing certain percentage of cement with fly ash. Trials on concrete mixes with replacement of 40%, 50%, 60% and 70% of cement with fly ash are carried out and the results depict that at the replacement level of 40% cement by fly ash, the required strength is achieved. It is also observed that the rate of early strength gain is retarded as the percentage replacement of cement increases. But in case of Geopolymer concrete (100% replacement of cement by fly ash) under a curing temperature around 600C and above, the strength gain rate is very high in initial stages. It is observed that design strength is achieved within 28 hours of oven curing. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Usage potential of melt processed plastic pellets as a substitute to fine aggregate in porous concretes(2012) Maneeth, P.D.; Lokesh, G.; Yaragal, S.C.; Babu Narayan, K.S.Porous concrete (PC) has been used for over 30 years. Because of its high porosity, the most common usages have been in the area of storm water management, but have been limited to use in pavements with low volume traffic, because of its low compressive strength compared to conventional concrete. Domestic and industrial plastic waste management has posed a serious challenge to engineers and scientists today. In this study an attempt is made to utilize plastic waste (melt processed) from small industries as a substitute for fine aggregate (up to 10%) in producing porous concretes. The recycled plastic (melt processed) was produced by drawing industrial and domestic waste plastic into long strands which were cut to small pieces forming granules. The plastic granules (pellets) are used as substitute to sand in this investigation. This experimental investigation reports the scope for plastic waste utilization as a substitute for fine aggregate and its influence on properties like porosity, permeability, compressive strength and tensile strength of porous concretes. © 2012 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Influence of silica fume on the strength of betostyrene mixed concrete(2013) Sambo, A.G.; Deepak, T.J.; Mithun, B.M.The main objective of this paper is to determine the influence of silica fume (SF) on betostyrene mix concrete. Extensive experimentation was carried out to determine the influence of SF on the workability, compressive strength and flexural strength of concrete at constant water-binder ratio of 0.40 and SF additive of 0%, 5%, 10%, and 15%. For all mixes, slump test, compaction factor, compressive and flexure strengths were determined at 7, 14 and 28 days. The results showed that the compressive and flexure strengths increased with silica fume incorporation. This study comprehensively produced lightweight concrete and showed a rise in strength as in direct proportionality to the increase in silica fume. Workability fell to a rising amount of silica fume. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.Item Acid, alkali, and chloride resistance of concrete composed of low-carbonated fly ash(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2017) Sahoo, S.; Das, B.B.; Mohammed Mustakim, S.This research investigates the effect of carbonated fly ash inclusion in concrete as partial replacement of cement on the durability performance when exposed to salt, sulfate, and acid solution. The effect of chemical exposure periods (30, 60, 90, and 120 days) on compressive strength and weight of concrete with low volume (25%) replacement of cement was investigated for various water curing ages (28, 56, 90, and 180 days). A comparative assessment with low volume (25% cement replacement) fly ash concrete and control concrete was also conducted. It was observed from the results that low volume carbonated fly ash concrete demonstrated a significant increase in resistance to loss in compressive strength and weight against salt, sulfate, and acid attack. Gray relation-based analysis was performed to determine suitable parameters for simultaneous minimization of strength loss and weight loss under chemical exposure. It can be recommended that, due to its cost-effectiveness, easy processing, and environmental friendly nature, carbonated fly ash can be adopted in construction as a partial replacement of cement in concrete. © 2016 American Society of Civil Engineers.Item Neutron radiation shielding properties of polymer incorporated self compacting concrete mixes(Elsevier Ltd, 2017) Malkapur, S.M.; Divakar, L.; Narasimhan, M.C.; Karkera, N.B.; Goverdhan, P.; Sathian, V.; Prasad, N.K.In this work, the neutron radiation shielding characteristics of a class of novel polymer-incorporated self-compacting concrete (PISCC) mixes are evaluated. Pulverized high density polyethylene (HDPE) material was used, at three different reference volumes, as a partial replacement to river sand in conventional concrete mixes. By such partial replacement of sand with polymer, additional hydrogen contents are incorporated in these concrete mixes and their effect on the neutron radiation shielding properties are studied. It has been observed from the initial set of experiments that there is a definite trend of reductions in the neutron flux and dose transmission factor values in these PISCC mixes vis-à-vis ordinary concrete mix. Also, the fact that quite similar enhanced shielding results are recorded even when reprocessed HDPE material is used in lieu of the virgin HDPE attracts further attention. © 2017 Elsevier LtdItem Experimental and Statistical Evaluations of Strength Properties of Concrete with Iron Ore Tailings as Fine Aggregate(American Society of Civil Engineers (ASCE) onlinejls@asce.org 1801 Alexander Bell DriveGEO Reston VA 20191 Alabama, 2020) Gayana, G.B.; Ram Chandar, R.C.Iron ore tailings (IOT) are the by-products of iron ore beneficiation, and these tailings are disposed of in several tons annually in quarries, landfills, and tailings dams, causing environmental issues. Various researchers have attempted to study the properties of IOT and the use of them in concrete as a building material. The present research aims to investigate the potential use of alccofine, a microfine particle of slag, as a cement replacement and IOT as fine aggregates in concrete. Experimental results indicated that the concrete workability decreased with an increase in the IOT-alccofine content and the maximum compressive strength (CS) obtained was 70.00, 68.67, and 65 MPa respectively at 40%, 30%, and 20% IOT-alccofine dosage for varying water-to-cement (w/c) ratios of 0.35, 0.40, and 0.45 respectively. Similarly, the flexural strength (FS) and splitting tensile strength (STS) increased with an increase in IOT-alccofine content. A statistically fitted multiple regression analysis was performed for all the mechanical properties to evaluate the significant level of concrete containing alccofine and IOT in concrete. These prediction models have high accuracy and low bias and the validation process represented that the equations can perform excellently in predicting the IOT-alccofine concrete properties. © 2019 American Society of Civil Engineers.