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    Experimental investigations on performance of concrete incorporating precious slag balls (PS Balls) as fine aggregates
    (Techno Press technop2@chollian.net, 2019) Sharath, S.; Gayana, G.B.; Reddy, K.R.; Ram Chandar, R.C.
    Substitution of natural fine aggregates with industrial by-products like precious slag balls (PS Balls) offers various advantages like technical, economic and environmental which are very important in the present era of sustainability in construction industry. PS balls are manufactured by subjecting steel slag to slag atomizing Technology (SAT) which imparts them the desirable characteristics of fine aggregates. The main objective of this research paper is to assess the feasibility of producing good quality concrete by using PS balls, to identify the potential benefits by their incorporation and to provide solution for increasing their utilization in concrete applications. The study investigates the effect of PS balls as partial replacement of fine aggregates in various percentages (20%, 40%, 60%, 80% and 100%) on mechanical properties of concrete such as compressive strength, splitting tensile strength, and flexural strength. The optimum mix was found to be at 40% replacement of PS balls with maximum strength of 62.89 MPa at 28 days curing. Permeability of concrete was performed and it resulted in a more durable concrete with replacement of PS balls at 40% and 100% as fine aggregates. These two specific values were considered as optimum replacement is 40% and also the maximum possible replacement is 100%. Scanning electron microscope (SEM) analysis was done and it was found that the PS balls in concrete were unaffected and with optimum percentage of PS balls as fine aggregates in concrete resulted in good strength and less cracks. Hence, it is possible to produce good workable concrete with low water to cement ratio and higher strength concrete by incorporating PS balls. © 2019 Techno-Press, Ltd.
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    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.