Browsing by Author "Avudaiappan, Siva"

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    Analyzing Influence of Mix Design Constituents on Compressive Strength, Setting Times, and Workability of Geopolymer Mortar and Paste
    (2023) Oyejobi, Damilola; Jameel, Mohammed; Adewuyi, Adekunle; Aina, Samuel; Avudaiappan, Siva; Maureira-Carsalade, Nelson
    Geopolymer concrete and mortar have evolved over the years as potential alternatives for reducing the greenhouse gases associated with cement production. This current research was aimed at investigating the optimum dosage and concentration of sodium hydroxide required to leach out silica and alumina oxides in the fly ash for geopolymerization to take place. Blackish grey fly ash from Morupule, Botswana, was synthesized by varying sodium hydroxide (NaOH) of 98% purity between 8 M and 14 M, respectively. The ratio influence of sodium hydroxide to fly ash in dissolving the oxides was carried out at the values of 0.55, 0.62, and 0.75. The results showed that the workability of the geopolymer mortar and paste decreased with the increase in the ratio of fly ash to alkaline activator. The highest workability was achieved at a ratio of 0.75 : 1. The compressive strength, setting time, and workability of geopolymer mortar and paste can be controlled by adjusting the ratio of fly ash to alkaline activator. A ratio of 1.5 : 1 was found to be the most suitable for achieving high compressive strength, while a ratio of 0.75 : 1 was found to be the most suitable for achieving high workability. Furthermore, the workability values were in the range of 105 to 143 mm, while the ranges of initial and final setting times were found to be between 280-350 and 950-1170 minutes, respectively. This study is significant because no previous study has carried out geopolmerization of the Morupule fly ash as a result of its unique characteristics. These findings have important implications for the development of sustainable construction materials. The main finding was that for optimum reaction to take place, and NaOH/fly ash ratio should be kept at 0.55 and molarity of 12 to avoid leaching of other oxides that might weaken the strength.
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    Biodegradable Green Composites: Effects of Potassium Permanganate (KMnO4) Treatment on Thermal, Mechanical, and Morphological Behavior of Butea Parviflora (BP) Fibers
    (2023) Abisha, M.; Priya, R. Krishna; Arunachalam, Krishna Prakash; Avudaiappan, Siva; Flores, Erick I. Saavedra I.; Parra, Pablo Fernando
    This study emphasizes the importance of utilizing biodegradable material Butea parviflora (BP) fiber for sustainable solutions. BP fiber offers numerous ecological benefits, such as being lightweight, biodegradable, and affordable to recycle. The study examines the effects of potassium permanganate (KMnO4) treatment on BP fiber and analyzes its physical and chemical behavior using various methods, including X-ray Diffraction (XRD) analysis, tensile testing, thermogravimetric analysis, thermal conductivity, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopic (FTIR) analysis. The results demonstrate that BP fiber possesses low density (1.40 g/cc) and high cellulose content (59.4%), which fosters compatibility between the matrix and resin. XRD analysis indicates a high crystallinity index (83.47%) and crystallite size (6.4 nm), showcasing exceptional crystalline behavior. Treated fibers exhibit improved tensile strength (198 MPa) and Young's modulus (4.40 GPa) compared to untreated fibers (tensile strength-92 MPa, tensile modulus-2.16 GPa). The Tg-DTA thermograms reveal the fiber's thermal resistance up to 240 degrees C with a kinetic activation energy between 62.80-63.46 KJ/mol. Additionally, the lowered thermal conductivity (K) from Lee's disc experiment suggests that BP fiber could be used in insulation applications. SEM photographic results display effective surface roughness for composite making, and FTIR studies reveal vibrational variations of cellulosic functional groups, which correlates with increased cellulosic behavior. Overall, the study affirms the potential of BP fiber as a reinforcing material for composite-making while emphasizing the importance of utilizing biodegradable materials for sustainability.
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    Innovative use of micronized biomass silica-GGBS as agro-industrial by-products for the production of a sustainable high-strength geopolymer concrete
    (2023) Jayanthi, V.; Avudaiappan, Siva; Amran, Mugahed; Arunachalam, Krishna Prakash; Qader, Diyar N.; Delgado, Manuel Chavez; Flores, Erick I. Saavedra; Rashid, Raizal S. M.
    Micronized biomass silica (MBS) and ground granulated blast furnace slag (GGBS) are agro-industrial byproducts generated by incinerating of rice husk (grinding in jar mill) and blast fur-naces that used produce iron, respectively. MBS accounts for 20% of the world's total paddy output of 590 million tons. These by-products (MBS and GGBS) have a high concentration of amorphous silica, which is utilized as a mineral additive in concrete. This amorphous silica in-teracts with hydration products, resulting in the formation of additional CSH gel. This improves concrete's strength and durability properties. Therefore, it is proven that inclusion of agro-industrial by-products in concrete helps to promote sustainable and greener development, which in turn reduces carbon footprints and waste that must be disposed of in landfills. There have been few investigations on concrete using MBS and demonstrated the great potential of employing MBS as a cement substitute or additive in normal concrete. Also, the utilization of MBS as partial replace to GGBS in geopolymer concrete (GPC) with different molarity is a novel aspect of this study. However, this study has the aim and limit to develop a high-strength eco-friendly GPC with agro-industrial byproducts (MBS and GGBS) for use in sustainable construction. The impact of incorporating MBS as a partial replacement of GGBS on compressive and split tensile strengths, sorptivity, and chloride permeability was tested up to the age of 28 days. MBS was used to replace GGBS in varying percentages in the preparation of concretes. MBS were used in con-crete at 0%, 10%, 20%, and 30% replacement by weight. It was discovered that a GPC combination containing MBS 20% and the balance GGBS as the binder had the best performance in terms of its strength and durability. The compressive strengths of all GPC mixtures exceeded the intended design strength. The main findings of this study demonstrated clearly that MBS may be employed as a binder in the production of GPC.
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    Innovative Use of Single-Use Face Mask Fibers for the Production of a Sustainable Cement Mortar
    (2023) Avudaiappan, Siva; Cendoya, Patricio; Arunachalam, Krishna Prakash; Maureira-Carsalade, Nelson; Canales, Cristian; Amran, Mugahed; Parra, Pablo F.
    Due to the COVID-19 epidemic, biomedical waste management has overwhelmed both developed and developing nations. It is now a critical issue that has to be addressed with minimal possible adverse impact on the environment. This study introduced a technique of recycling face masks into polypropylene fibers for use in concrete. This proposed recycling process provides complete disinfection of contaminated clinical waste and offers the opportunity to transform the characteristics of an end product. Microfibers manufactured from recycled medical masks were subjected to testing. According to the results, polypropylene is the primary component of this research program. Two batches of concrete were made, one with the inclusion of masks as polypropylene fibers and another that performed as a control mix. The modified mortar was compared to the control mix in split tensile, flexure, compressive strength, and water absorption. Compressive strength was found to be improved by about 17%, and tensile strength to be increased by around 22% when mask fibers were incorporated. This research introduced a novel approach for disposing of waste masks and established the preliminary viability of upcycling trash face masks towards mortar concrete production.
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    Mechanical Behaviour and Impact of Various Fibres Embedded with Eggshell Powder Epoxy Resin Biocomposite
    (2022) Sivakumar, Aburpa Avanachari; Sankarapandian, Sankarasabapathi; Avudaiappan, Siva; Flores, Erick I. Saavedra
    Natural fiber composites are becoming an alternate material to synthetic fiber composites, and the use of eggshell bio-filler has been explored in polymer composites as environmental protection. Jute, coir, and sisal fibers were utilized in this research to make composites out of natural fibers. Polymer composites were made using epoxy resin with different amounts of eggshell powder (ESP) as fillers (2%, 4%, 6%, 8%, and 10% of weight). The mechanical and biodegradability properties of the synthesized composites were investigated. The testing results showed that composites with an optimum percentage of 6% ESP as filler improved mechanical characteristics significantly in all three fiber composites. Among the three fibers, coir fiber with 6% ESP added showed a substantial increase in tensile, flexural, impact, and hardness strength properties by 34.64%, 48.50%, 33.33%, and 35.03%, respectively. In addition, the percentage weight loss of coir fiber composites at 9 weeks is noteworthy in terms of biodegradability testing. As a result, epoxy composites containing eggshell fillers could be employed in applications requiring better tensile, flexural, impact, and hardness strength.
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    Performance of recycled Bakelite plastic waste as eco-friendly aggregate in the concrete beams
    (2023) Mohan, R.; Chakrawarthi, Vijayaprabha; Nagaraju, T. Vamsi; Avudaiappan, Siva; Awolusi, T. F.; Roco-Videla, Angel; Azab, Marc; Kozlov, Pavel
    The use of plastic waste as a partial or complete replacement for coarse aggregate in concrete mixtures has been studied in recent years. However, the quality and quantity of coarse plastic waste particles have been a challenge. This study aims to investigate the mechanical performance of concrete with Bakelite plastic waste as a partial replacement for coarse aggregate. Six different concrete mixtures with various Bakelite dosages, ranging from 0 % to 10 %, were tested. The results indicate that the addition of Bakelite plastic alters the behaviour of the concrete and re-duces compressive and flexural strengths at lower dosages. The inclusion of Bakelite waste in concrete mixtures generally leads to a decrease in compressive and split tensile strength, with the exception of the mixture containing 6 % Bakelite, which showed increased strength. Although there is a slight reduction in flexural strength, Bakelite waste prevents sudden specimen breakage and maintains specimen integrity. The ultimate load capacity of reinforced concrete beams with Bakelite waste is generally lower compared to the control beam, except for the 8 % waste Bakelite beam which demonstrated a similar ultimate load capacity of 60 kN. Although managing Bakelite waste can be difficult because it can lead to the creation of microplastics in landfills over time, utilizing Bakelite waste in concrete can be a sustainable method of waste management. The innovative use of Bakelite waste as a partial replacement for coarse aggregate in concrete offers a sustainable solution to the problem of waste management and addresses the environmental concerns related to the disposal of non-biodegradable plastics. This research provides a practical solution for developing eco-friendly and cost-effective construction materials while promoting sustainable waste management practices.