Role of red mud as a cementing material in concrete: a comprehensive study on durability behavior

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Role of red mud as a cementing material in concrete: a comprehensive study on durability behavior Chava Venkatesh1 · Ruben Nerella1   · Madduru Sri Rama Chand2 Received: 7 July 2020 / Accepted: 12 September 2020 © Springer Nature Switzerland AG 2020

Abstract Red mud (RM), a semi-solid residual of the alumina refinery process, has higher alkalinity, and its disposal leads to environmental imbalance. To overcome this issue, RM is partially replaced with cement in the range of 0% to 20% at an interval of 5%. The present research work majorly focused on durability and micro-level concrete studies containing pre-calcined (600 °C in 2 h) RM. The tests on red mud concrete, viz. compressive strength, sorptivity test, open porosity test, rapid chloride penetration test, accelerated corrosion test, water absorption test, X-ray diffraction, scanning electron microscope (SEM), and energy-dispersive spectroscope (EDS) analysis, have been conducted to investigate the comprehensive characterization of concrete with RM. From the compressive strength test results, maximum strength was observed at 10% replacement. Open porosity, chloride ions permeability, water absorption, and sorptivity values showed reduction at an increment of RM replacement level. RM concrete offered more corrosion resistance due to high alkalinity, which possessed a pH of more than 12.5. From the micro-level investigations such as SEM and EDS, higher C–S–H gel formation was observed in RM 10% replacement concrete. In the meantime, less number of pores was observed in all RM replaced concrete mixes. Keywords  Accelerated corrosion test · Durability properties · Red mud · Open porosity test · Sorptivity test · XRD

Introduction In the alumina refinery process, raw bauxite ore is treated with concentrated NaOH solution at high pressure; thus, the semi-solid residuals are disposed off from filters, which was considered as “red mud (RM).” In the production of one ton alumina, nearly 1.5 to 2 tons of RM is disposed off, resulting in 140 million tons per annum worldwide [1]. RM, due to the presence of a higher percentage of sodium hydroxides, possesses greater alkalinity, and disposal of such material leads to rigorous ecological issues. At present, alumina industries are following the pond disposal, sea * Ruben Nerella [email protected] Chava Venkatesh [email protected] Madduru Sri Rama Chand [email protected] 1



Civil Engineering, Vignan’s Foundation for Science Technology and Research, Guntur, AP, India



Sree Chaitanya College of Engineering, Karimnagar, Telangana, India

2

disposal, lagooning disposal, and dry stacking methods for disposal of red mud; however, it creates some of the major environmental issues [2–5]. The solution to surmount this problem has been addressed by a few researchers who suggested utilizing the unprocessed or processed red mud as a raw material in various construction industries like brick industries and ceramic-based industries [6–9]. Very few studies were conducted on red mud as supplementary

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