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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.
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.
Characterisation of Sodium Acetate Treatment on Acacia pennata Natural Fibres
(2023) Sheeba, Kasirajan Rajam Jaya; Priya, Retnam Krishna; Arunachalam, Krishna Prakash; Avudaiappan, Siva; Maureira-Carsalade, Nelson; Roco-Videla, Angel
The present study concerns the physico-chemical, structural, mechanical and thermal characterization of Acacia pennata, a natural and almost inexpensive fibre, as a potential reinforcement in polymer composites. The effect of treating the fibre with sodium acetate to increase its qualities has been seen through the use of thermogravimetric analysis, scanning electron microscope (SEM) analysis, X-ray diffraction (XRD), mechanical property tester, and Fourier transform infrared spectroscopy (FTIR). According to XRD analysis, the elimination of lignin and wax-like impurities resulted in an increase in the AP fibre's crystalline index (79.73%). The fibre's thermal stability was also discovered to be 365 degrees C. Tensile strength (557.58 MPa) and elongation at break both increased by 2.9% after treatment with sodium acetate. The surface nature and quality of AP fibres improved after sodium acetate treatment. It was confirmed by the reduction of chemical compositions (such as hemicellulose, lignin and pectin). Given its density, the fibre can be suggested as a reinforcement in polymer composites for light-weight applications because its lightweight property will be more useful for composite manufacturing.
Enhancing structural, thermal, and mechanical properties of Acacia pennata natural fibers through benzoyl chloride treatment for construction applications
(2023) Sheeba, K. R. Jaya; Priya, R. Krishna; Arunachalam, Krishna Prakash; Avudaiappan, Siva; Flores, Erick Saavedra; Kozlov, Pavel
In recent years, there has been growing interest in exploring natural fiber reinforced composites as potential alternatives to conventional materials in various structural applications. The aim of this study on Acacia pennata fibers (APFs) and treating them with benzoyl chloride was to explore their potential as reinforcement in construction-related materials. The aim was to investigate the physico-chemical, thermal, and mechanical properties of these fibers to understand their suitability for applications in concrete reinforcement, retrofitting, roofing, and wall panels. By enhancing the understanding of the treated fibers' characteristics, this study contributes to the development of sustainable and high-performance construction materials. The fibers were extracted using both water retting and chemical retting methods. The physico-chemical properties of the fibers were assessed through X-ray diffraction (XRD) analysis, which determined a calculated crystalline index (CI) of 72.14% and a crystalline size of 2.6 nm. Thermo-gravimetric analysis was conducted to evaluate the thermal stability of the APFs, revealing a temperature of 366 degrees C and a maximum degradation temperature of 226.7 degrees C. Mechanical analysis included measurements of the APFs' tensile strength (467.86 MPa), tensile modulus (14.62 GPa), microfibrillar angle (14.79), and elongation at break (3.2%). The findings derived from these analyses suggest that the APFs that underwent treatment exhibit desirable mechanical characteristics, rendering them a viable option for utilization in construction-related materials like reinforcement in concrete, retrofitting, roofing and wall Pannels. This research presents a novel exploration of Acacia pennata fibers (APFs) treated with benzoyl chloride, aiming to establish their potential as reinforcements for construction materials. While natural fiber-reinforced composites have drawn interest, the unique application of APFs in construction and their treatment with benzoyl chloride to enhance properties remain relatively unexplored in the literature. This study fills a significant
Examining the physico-chemical, structural and thermo-mechanical properties of naturally occurring Acacia pennata fibres treated with KMnO₄
(2023) Sheeba, K. R. Jaya; Priya, Retnam Krishna; Arunachalam, Krishna Prakash; Shobana, S.; Avudaiappan, Siva; Flores, Erick Saavedra
Natural fiber is a viable and possible option when looking for a material with high specific strength and high specific modulus that is lightweight, affordable, biodegradable, recyclable, and eco-friendly to reinforce polymer composites. There are many methods in which natural fibres can be incorporated into composite materials. The purpose of this research was to evaluate the physico-chemical, structural, thermal, and mechanical properties of Acacia pennata fibres (APFs). Scanning electron microscopy was used to determine the AP fibers' diameter and surface shape. The crystallinity index (64.47%) was discovered by XRD. The irregular arrangement and rough surface are seen in SEM photos. The findings demonstrated that fiber has high levels of cellulose (55.4%), hemicellulose (13.3%), and low levels of lignin (17.75%), which were determined through chemical analysis and validated by Fourier Transform Infrared Spectroscopy (FTIR). By using FTIR, the functional groups of the isolated AP fibers were examined, and TG analysis was used to look into the thermal degrading behaviour of the fibers treated with potassium permanganate (KMnO4) Due to their low density (520 kg/m(3)) and high cellulose content (55.4%), they have excellent bonding qualities. Additionally, tensile tests were used for mechanical characterisation to assess their tensile strength (685 MPa) and elongation.
Experimental Investigation on Composite Deck Slab Made of Cold-Formed Profiled Steel Sheeting
(2021) Avudaiappan, Siva ; Saavedra Flores, Erick I. ; Araya-Letelier, Gerardo ; Thomas, Walter Jonathan ; Raman, Sudharshan N. ; Murali, Gunasekaran; Amran, Mugahed ; Karelina, Maria ; Fediuk, Roman ; Vatin, Nikolai
An experimental investigation is performed on various cold-formed profiled sheets to study the connection behavior of composite deck slab actions using bolted shear connectors. Various profiles like dovetailed (or) re-entrant profiles, rectangular profiles and trapezoidal profiles are used in the present investigation. This experimental investigation deals with the evaluation of various parameters such as the ultimate load carrying capacity versus deflection, load versus slip, ductility ratio, strain energy and modes of failure in composite slab specimens with varying profiles. From the test results the performance of dovetailed profiled composite slabs' resistance is significantly higher than the other two profiled composite deck slabs.
Experimental investigation on the physical, microstructural, and mechanical properties of hemp limecrete
(2023) Avudaiappan, Siva; Cuello Moreno, Pablo Ignacio; Montoya R, Luis Felipe; Chavez-Delgado, Manuel; Arunachalam, Krishna Prakash; Guindos Bretones, Pablo; Marzialetti B, Teresita; Fernando Parra, Pablo; Saavedra Flores, Erick I; Flores Arrey, Julio Ignacio
Experimental investigations on sustainable mortar containing recycled seashell powder as cement partial replacement
(2024) Ahmed, Saddam M.; Chavez-Delgado, Manuel; Avudaiappan, Siva
Creating sustainable mortar containing recycled seashells is an innovative approach that can contribute to environmental conservation and reduce waste. The use of seashells as a partial replacement for traditional raw materials in mortar can have several benefits, including conservation of natural resources, waste reduction, and improved material properties. The current study uses Marsh Clam seashells after crushing the cleaned seashells into powder. Heated ( up to 600C degrees) and unheated seashells were considered in the experimental investigation. In both batches, a seashell powder (heated and unheated) was replaced with OPC cement in proportions of 6, 9 and 12% in the mixing process. XRD, SEM, EDS and mechanical tests were employed to determine the crystal structure and to provide a comprehensive understanding of the physical, chemical, and structural characteristics of the substance. The study concluded that the calcium carbonate (CaCO3) that is nature chemical form of seashells was turned to calcium oxide (CaO) during the heating process and the resulted product was highly reactive with water, improved microstructural properties of the concrete. It also promotes better particle packing, reduce porosity, and create a denser, more uniform concrete matrix and enhancing the overall performance of the material.
Experimental Study on the Mechanical Properties and Microstructures of Cenosphere Concrete
(2023) Arunachalam, Krishna Prakash; Avudaiappan, Siva; Flores, Erick I. Saavedra; Parra, Pablo Fernando
The most valuable components of coal fly ash are cenospheres. Cenospheres are hollow spherical particles produced during the coal-burning processes. As a result of their excellent characteristics, such as high workability, high heat resistance, low bulk density, and high strength, cenospheres can be used in the manufacturing of lightweight cement concrete. The research efforts and outcomes are to produce long-lasting cement-based lightweight concrete (LWC) composites with good mechanical properties. The novelty of this investigation is to determine the cement concrete strength when silica fume (SF) and cenospheres (CS) were used as a replacement for cement. Throughout the experiments, a consistent substitution of 12% silica fume was incorporated into cement mass. Silica is used as a micro filler and pozzolanic reactant to strengthen concrete. The concrete mixtures were tested to ensure they met the requirements of the lightweight concrete in terms of their mechanical, physical, and durability qualities. According to the findings, lightweight concrete standards were met, and environmental sustainability was improved with the use of these mix proportions. Concrete specimen's self-weight decreases by 35% with 30% cenosphere as a replacement. The micrograph shows the lack of portlandite is filled by mullite and other alumino silicates from the cenosphere. In order to achieve sustainability in concrete manufacturing, these mixtures can be suggested for the making of structural LWC that makes use of a large volume of industrial waste while conserving cement and natural resources.
Improving concrete underground mining pavements performance through the synergic effect of silica fume, nanosilica, and polypropylene fibers
(2021) Brescia-Norambuena, Leonardo; Gonzalez, Marcelo; Avudaiappan, Siva; Saavedra Flores, Erick, I; Grasley, Zachary
Concrete pavements for underground mining are in service under very aggressive exposure conditions (heavy loads and chemical attacks), which reduce their service life and affect mining productivity. Aiming to improve the concrete's performance, the combined use of silica fume, nanosilica, and polypropylene fibers was investigated. While each of these materials contributes independently to improving concrete performance, the similar chemistry of nanosilica and silica fume and the considerable workability loss by using each of these materials could negatively impact the concrete properties when used together. Therefore, it is necessary to demonstrate the synergy of using these three materials together, and quantify their relevance in the concrete response. In comparison to the control mix, the concrete mixes with the combined additions showed an average improvement of i) 17% of compressive strength, ii) 23% of splitting strength, and iii) 22% of flexural strength, iv) 200% of the surface resistivity, v) 212% of the abrasion resistance, and vi) 158% of less sulfate expansion. As the numerical modelling of the results indicated a statistically significant interaction between the independent variables, it is proposed that the silica fume, nanosilica, and fibers act synergically, enhancing the underground mining pavements. (C) 2021 Elsevier Ltd. All rights reserved.
Innovative use of copper mine tailing as an additive in cement mortar
(2023) Arunachalam, Krishna Prakash; Avudaiappan, Siva; Maureira, Nelson; Garcia Filho, Fabio Da Costa; Monteiro, Sergio Neves; Batista, Isabela Devesa; de Azevedo, Afonso R. G.
This research assesses the feasibility of recycling copper mine tailings (CMT) by analyzing the durability and mechanical characteristics of cement mortar using these tailings as filler additives. CMT are mineral wastes generated during the process of mining. In this work, specimens of cement mortar were incorporated with up to 30 wt.% of a CMT. Bulk density, dynamic modulus of elasticity, apparent density, ultrasonic pulse velocity, flexural and compressive strengths tests were evaluated. Total amount of voids, sorptivity, water ab-sorption and chemical resistance tests were also obtained to evaluate the mortar durability. When 10 wt.% CMT was incorporated, overall amount of voids in the mortar was reduced by 20% and mechanical performance was improved by 16% after 28 days. The flexural strength of the mortar was also found to increase, with the 20% wt.% CMT mortar incorporation reaching a flexural strength of 5.89 MPa. Thus represents 16% increase compared to the control 0% CMT strength. The results indicated that there was not a perfect correlation be-tween these results and the mechanical strength results for the 15 and 20 wt.% CMT mortars. In addition, the CMT acts as a protective barrier against harmful chemicals. The results of this research indicate that reusing CMT by incorporating into cement mortar is a feasible method for their recycling. Mortar made with as much as 15 wt.% CMT presented the same strength and durability as mortar with traditional sand and cement. (c) 2023 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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.
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.
Investigating the Mechanical, Thermal, and Crystalline Properties of Raw and Potassium Hydroxide Treated Butea Parviflora Fibers for Green Polymer Composites
(2023) Mohan, Abisha; Priya, Retnam Krishna; Arunachalam, Krishna Prakash; Avudaiappan, Siva; Maureira-Carsalade, Nelson; Roco-Videla, Angel
The only biotic factor that can satisfy the needs of human species are plants. In order to minimize plastic usage and spread an immediate require of environmental awareness, the globe urges for the development of green composite materials. Natural fibers show good renewability and sustainability and are hence utilized as reinforcements in polymer matrix composites. The present work concerns on the usage of Butea parviflora fiber (BP), a green material, for high end applications. The study throws light upon the characterization of raw and potassium hydroxide (KOH)-treated Butea Parviflora plant, where its physical, structural, morphological, mechanical, and thermal properties are analyzed using the powder XRD, FTIR spectroscopy, FESEM micrographs, tensile testing, Tg-DTA, Thermal conductivity, Chemical composition, and CHNS analysis. The density values of untreated and KOH-treated fibers are 1.238 g/cc and 1.340 g/cc, respectively. The crystallinity index of the treated fiber has significantly increased from 83.63% to 86.03%. The cellulose content of the treated fiber also experienced a substantial increase from 58.50% to 60.72%. Treated fibers exhibited a reduction in both hemicelluloses and wax content. Spectroscopic studies registered varying vibrations of functional groups residing on the fibers. SEM images distinguished specific changes on the raw and treated fiber surfaces. The Availability of elements Carbon, Nitrogen, and Hydrogen were analyzed using the CHNS studies. The tensile strength and modulus of treated fibers has risen to 192.97 MPa and 3.46 Gpa, respectively. Thermal conductivity (K) using Lee's disc showed a decrement in the K values of alkalized BP. The activation energy Ea lies between 55.95 and 73.15 kJ/mol. The fibers can withstand a good temperature of up to 240 & DEG;C, presenting that it can be tuned in for making sustainable composites.
Investigation on Properties of Raw and Alkali Treated Novel Cellulosic Root Fibres of Zea Mays for Polymeric Composites
(2023) Kavitha, S. Anne; Priya, R. Krishna; Arunachalam, Krishna Prakash; Avudaiappan, Siva; Maureira-Carsalade, Nelson; Roco-Videla, Angel
Today, new materials based on natural fibres have been emerging day by day to completely eradicate plastics to favour our environmental nature. In this view, the present work is based on the extraction and characterisation of the novel root fibres of the Zea mays (Zm) plant, grown by the hydroponic method. Both the dried untreated and alkali treated root fibres are investigated using a variety of structural, morphological, thermal, elemental and mechanical tests by subjecting both the samples to p-XRD, FT-IR, SEM-EDAX, TGA-DTA, CHNS and tensile strength analyses. Thermal conductivity of the untreated and treated fibres is found using Lee's disc experiment. From p-XRD analysis, the Crystallinity Index, Percentage Crystallinity and Crystallite size of the samples are found. FT-IR studies clarify the different vibrational groups associated with the fibre samples. SEM images show that the surface roughness increases for the chemically treated samples, such that it may be effectively utilised as reinforcement for polymeric composites. The diameter of the fibre samples is found using SEM analysis. According to the EDAX spectrum, Zm fibres in both their raw and processed forms have high levels of Carbon (C) and Oxygen (O). The TGA-DTA tests revealed that the samples of natural fibre have good thermal characteristics. CHNS studies show that Carbon content is high for these samples, which is the characteristic of many natural fibres. Chemical analysis is used to ascertain the prepared samples' chemical makeup. It reveals that both samples have significant amounts of cellulose. The density of the fibres is found to be in the range 0.3-0.6 g/cc, which is much less than any other natural fibre. Therefore, it can be used in light weight applications. From the tensile strength analysis, physical properties such as Young's modulus and micro-fibril angle are determined. The fibres in the roots exhibit a lower tensile strength. Thus, these fibres can be used in powdered form as reinforcement for natural rubber or epoxy composites. After examining all of its properties, it could be reasonably speculated that Zea mays root fibres can be considered as an efficient reinforcement for various matrices to produce attractive bio-composites.
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.
Microstructure and Water Retention Kinetics in Autogenous Cured Self-Compacting Concrete Blends Using Super Absorbent Polymer
(2023) Laila, Lija Rajamony; Karmegam, Aarthi; Avudaiappan, Siva; Flores, Erick I. Saavedra
This research aimed to determine how a super absorbent polymer affects the microstructural characteristics and water retention kinetics of a new composite made by substituting granite pulver (GP) and fly ash (FA) for cement. Understanding the mechanics of water movement is crucial for comprehending the effectiveness of autogenous curing. Several experiments were conducted to analyze the water mitigation kinetics of super absorbent polymer (SAP) in the hydrating cement paste of autogenous cured self-compacting concrete (GP-ACSSC) mixtures. In the first hours following casting, water sorptivity, water retention, and hydration tests were carried out. The effects of various concentrations of SAP and GP, which was utilized as an alternative cement for the production of sustainable concrete that leads to reduction in carbon footprint, on the autogenous cured self-compacting concrete with reference to the abovementioned properties were explored. The investigation showed that releasing the curing water at a young age, even around the beginning of hydration, allowed homogenous and almost immediate distribution of water across the full cured paste volume, which improved the water retention kinetics. Compared to the control mixtures, the addition of SAP up to 0.6% and the substitution of cement with GP up to 15% had favorable impacts on all water kinetics parameters.
Performance evaluation of super absorbent polymer modified cement mortar with nano-silica/GGBS
(2023) Muthalvan, Renuka Senthil; Selvaraj, Loknath; Avudaiappan, Siva; Liseitsev, Yury
Modified cement mortar plays a major role in enhancing the properties of conventional cement mortar such as strength, durability, better adhesion, reduce porosity and shrinkage and improve workability. Certain modifiers, like industrial by-products, can be incorporated into mortars to promote sustainability and reduce environmental impact. The main aim of this study is to develop Super Absorbent Polymer Modified cement mortars with Nano Silica/GGBS. In this study, con-ventional cement mortar blended with Nano Silica and Super Absorbent Polymer (SAP) as one combination then GGBS and SAP blended mortar as another combination was examined to mitigate the negative impact of SAP. Ternary Blended cement mortars prepared with various SAP dosages of 0.25% of cement and 0.5% of cement. Nano-Silica is an additive used in the range of 1%, 1.5%, and 2% of the weight of cement. A combination containing GGBS and SAP, GGBS is a replacement for cement in the range of 15%, 30%, and 45% to the weight of cement. The com-bined effect of altering SAP and Nano-silica/GGBS composition on the mechanical, durability, and microstructural properties were studied using experimental investigation. Peak improvement in the compressive strength of the control mix of 6.52% is noted in the mix combination that contains 0.25% SAP and 15% GGBS replacement. The durability test revealed that the weight loss minimized by 19.58% and strength loss minimized by 36.17% due to acid attack is noted in the combination of GGBS and SAP. Weight loss minimized by 36.17% and strength loss minimized by 22.71% due to sulphate attack is noted in a mix containing GGBS. From experimental investi-gation, 30% & 45% GGBS replacement in place of cement had no significant improvement in mechanical, durability, and microstructural properties compared to 15% GGBS replacement, which optimum obtained in this study to alleviate the negative consequence of SAP when used as an internal curing agent.
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.
Prediction of the mechanical properties of concrete incorporating simultaneous utilization of fine and coarse recycled aggregate
(Pontificia Universidad Católica de Chile. Escuela de Construcción Civil, 2023) Joseph, Herbert Sinduja; Pachiappan, Thamilselvi; Avudaiappan, Siva; Guindos Bretones, Pablo
The mechanical properties of concrete were optimized using response surface methodology (RSM) and fuzzy logic. The aggregate portion of the concrete was replaced with recycled aggregate to address the environmental problems caused by building demolition wastes. The essential key factors that influenced the suitability of recycled aggregate in concrete applications are the compressive strength (CS), flexural strength (FS), and the split tensile strength (STS). The experiments were designed with nine combinations of two input factors (percentage of coarse and fine recycled aggregates) at different levels 30, 60, and 100%. Furthermore, optimization techniques were used to determine the strong correlations between the variables and the mechanical parameters. Such optimization techniques helped to identify the optimistic max-imum strength for replacing 44% coarse and 65% fine recycled aggregate. Using RSM, the maximum strength results were found to be: CS at 7, 28, 56, and 90 days were 23.61, 35.04, 40.02, and 43.63 N/mm2, respectively, FS 3.6 N/mm2 and STS 2.0 N/mm2. The maximum strength parameters were found using fuzzy logic: CS at 7, 28, 56, and 90 days were 23.5, 35.8, 41, and 46.7 N/mm2, respectively, FS 4.13 N/mm2 and STS 1.97 N/mm2. Such optimization can be carried out to lower the material wastage, energy consumption, and expenses for the production.

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