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    Combined effect of marine environment and pH on the impedance of reinforced concrete studied by electrochemical impedance spectroscopy
    (Springer, 2019) Goudar, S.K.; Das, B.B.; Arya, S.
    In the present investigation, behavior of OPC and fly ash based concretes were assessed by electrochemical impedance spectroscopy (EIS) technique after exposing the samples to the marine environment in combination with five pH levels (1, 4, 7, 10, and 13). Three different dosages of fly ash (15, 25, and 35%) were used to produce fly ash based concretes. After 90 days of exposure to the aggressive environment, the OPC and fly ash based concretes were tested for impedance analysis and corrosion resistance by electrochemical studies. For the equivalent electrical circuit in EIS study, a total of four electrical circuits were tried for the possible best fit of obtained Nyquist plots. The equivalent electrical circuits proposed by previous researchers failed to provide the best fit for the obtained Nyquist plots. A new equivalent electrical circuit is being proposed in this study which will provide the possible best fit of Nyquist plots when the concrete is being exposed to acidic and alkaline marine environment. It is observed that the pH of the marine environment has a decisive influence on the impedance of reinforced concrete. As the acidity of marine environment reduces to pH 1, the impedance of OPC and fly ash based concrete reduced significantly due to the severe deterioration of concrete composites especially because of acid attack and Cl− ions migration. However, in the case of alkaline nature of the marine environment (pH 13), there was comparably less deterioration of concrete composites which reflected in higher impedance values. The higher dosage of fly ash addition has led to substantial improvement in concrete impedance and also lower corrosion rate. © Springer Nature Singapore Pte Ltd. 2019.
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    Characterization of Mechanical and Microstructural Properties of FA and GGBS-Based Geopolymer Mortar Cured in Ambient Condition
    (Springer, 2021) Prasanna, K.M.; Tamboli, S.; Das, B.B.
    Fly ash-based geopolymer mortars require heat curing to achieve its properties, which limits its practical application at ambient conditions. The present study was aimed to accomplish the need for application of fly ash-based geopolymers for practical viability without any heat curing by inclusion of ground-granulated blast furnace slag (GGBS). The results revealed that inclusion of GGBS as a partial replacement to fly ash (FA) in geopolymer mortar, which is cured in ambient curing condition, can be able to achieve required setting time and compressive strength. Amalgamation of GGBS with class FA as binder in geopolymerization lend a hand to attain compressive strength as well as setting time which is analogous to ordinary Portland cement (OPC). Microstructural properties were studied using scanning electron microscopy. © 2021, Springer Nature Singapore Pte Ltd.
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    Fly ash-reinforced poly(vinyl alcohol) composites
    (Elsevier, 2021) Anandhan, S.; SelvaKumar, S.; Patil, A.G.
    Fly ash (FA) is a waste residue and huge amounts of it have been produced from coal-fired power plants. As a result, it has become a serious issue and there is an urgent need to reduce its accretion as well as improve the safe disposal of FA as it has many toxic constituents including lead, arsenic, and chromium. In an effort to utilize FA, it has been widely used as filler for fabricating polymer composites to improve their performance. Recently, FA-incorporated polymers have received the attention of researchers and industries due to their remarkable properties, such as improved mechanical strength without sacrificing their elasticity, thermal, flame resistance, wettability, resistance to hydrolysis, and possessing excellent dynamic mechanical properties even at low temperatures. In comparison with conventional FA-based polymer composites, those based on surface-modified FA and nanostructured FA (NFA) exhibit superior mechanical and technical properties. The present article reviews various aspects of poly(vinyl alcohol)/FA-based composites. It also focuses on the effect of particle size reduction of FA on the physicochemical properties of poly(vinyl alcohol)/NFA composites. © 2022 Elsevier Inc. All rights reserved.