Department of Civil Engineering
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Item Life-Cycle Assessment of Production of Concrete Using Copper Tailings and Fly Ash as a Partial Replacement of Cement(Springer, 2020-04-18) Singh, Ajit PratapUtilization of anthropogenic wastes in the production of building materials is an utmost necessity in the present-day context. The primary objective of this study is to assess the impact of concrete production on the surrounding environment due to partial replacement of cement with copper tailings and fly ash. In this study, global warming potential (GWP) and emissions resulted due to the production of concrete have been comprehensively quantified using life-cycle assessment (LCA) analysis. While performing the analysis, all important resources (like electrical energy, raw materials used, and water consumption associated with procurement, utilization, maintenance, and recycling to their final disposal) have been considered. The guiding consensus frameworks, nomenclatures, and different available methodologies have been referred from ISO 14040. For concrete, one cubic meter has been taken as a functional unit throughout the study for evaluation and comparing all the parameters. To perform LCA analysis, UMBERTO NXT tool has been used by taking into consideration of input parameters associated with the proportion of raw materials used in the production of concrete (e.g., cement, sand, aggregates, admixtures, fly ash, copper tailings, and water), its storage and transportation, and distribution. The results obtained from the study demonstrates how the utilization of alternative wastes materials is beneficial in the production of concrete while minimizing adverse environmental impact in a sustainable manner.Item Alternative materials for wearing course of concrete pavements: A critical review(Elsiever, 2020-03-10) Singh, Ajit Pratap; Sarkar, Askoke Kumar; Lahoti, MukundThe existing worldwide road length of concrete pavements is significant. Furthermore, concrete pavements have a number of specific applications, even though they are second to asphalt pavements in terms of current popularity. Besides, asphalt is a rapidly depleting resource, which might mean that concrete is the chief material for the future. However, concrete pavements have their drawbacks, such as high construction cost, low tensile strength, and significant contribution to global carbon-di-oxide emissions. The present study aims to address these drawbacks by reviewing the prominent alternative materials that may be utilized to replace cement and/or aggregates in concrete. The potential of alternatives such as coal ash, silica fume, nano-silica, fly ash, slag, and recycled concrete aggregate is investigated. In addition, the effects of adding fibers (as both fiber-reinforced concrete and engineered cementitious composite) to concrete pavements are discussed. This review will also help pavement engineers and researchers to ascertain which combination of materials to use so that mechanical properties better than conventional concrete are achieved. The specific advantages and disadvantages due to various combinations of materials, in several types of concrete pavements such as conventional concrete, roller-compacted concrete, and self-compacting concrete are discussed in detail.Item Utilization potential of fly ash and copper tailings in concrete as partial replacement of cement along with life cycle assessment(Elsiever, 2019-11) Singh, Ajit PratapFly ash (FA) and copper tailings (CT) both are, anthropogenic wastes, spread all over the globe due to rapid growth in thermal power plants and progressive increase in the demand of copper. This study examines the feasibility of combined utilization of FA and CT in concrete as a partial replacement of cement by assessing compressive strength, cost, and environmental impact. Morphology and constituent minerals of FA and CT have been identified to understand the utilization potential. Subsequently, the concrete has been designed for 30 MPa target strength as per IS 10262:2009 for different mix proportions of FA and CT. Improvement (up to 8.27% compared to the control mix) in the compressive strength has been observed at combined replacement of 10% FA and 5% CT. The cost of concrete can also be reduced up to 16% without compromising its compressive strength. The environmental impact assessment of the modified concrete mix proportions has also been performed using life cycle assessment (LCA) as per ISO 14040:2006. Effect of all raw materials, electricity, and water consumption have been considered from their cradle to grave approach. One cubic meter concrete has been taken as a functional unit in LCA. Notable reduction has been observed in the chosen midpoint categories up to 38% in climate change, up to 32.6% in human toxicity, up to 33.6% in ozone depletion, up to 31.9% in agriculture land occupation, water depletion up to 34.3%, fossil depletion up to 34.8%, particulate matter up to 35.4%, and metal depletion up to 25.2%.