Resumo em Inglês:

Concrete is an unavoidable element in modern construction. During concrete production enormous amount of CO2 is emitted which results in global warming. From the point of view of environmental protection, sustainable concrete production should be focused on. An eco-friendly solution to lessen the impact on the environment has been briefed in this article. Ground Granulated Blast furnace Slag (GGBS) and cement kiln dust have been partially replaced with cement. The strength and durability properties of GGBS and cement kiln dust-incorporated concrete were evaluated and presented. The optimal substitution percentage of GGBS and cement kiln dust was reckoned as 15% and 12% respectively. The test results fortified that the replacement of GGBS and cement kiln dust for cement in concrete becomes an eco-friendly solution from the point of view of quality and sustainability.

Resumo em Inglês:

In the present study, Response Surface Methodology model (RSM) and Artificial Neural Network model (ANN) is presented to forecast the ultimate moment capacity of ferrocement using 2 variable process modelling (volume fraction and steel slag replacement). The RSM and ANN model’s outcomes are contrasted with those of other existing models, like plastic analysis, mechnaism approcah, simplified method, group method of data handling, the results shows that ferrocement with steel slag replacement of 25% and chicken mesh volume fraction (Vr) of 4.35% has maximum experimental moment capacity of 253.33 kN-mm and predicted moment capacity using RSM and ANN is 244.70 kNmm and 255.88 kNmm respectively. The adopted ANN have a regression value of 0.9882 and 0.98863 for training and testing respectively. The outcomes of the analysis of variance show that the provided models are very suitable since the p value is less than 0.005, the projected R2 and the adjustable R2 is less than 20%. Moreover, the flexural moment of ferrocement composites is more significantly affected by the Vr. According to the findings of the surface plot, Pareto chart, and regression analysis, the Vr is the most important and crucial factor for the flexural moment of ferrocement composites.

Resumo em Inglês:

Sand mining from riverbeds has been a vital component of the construction industry for decades, providing a fundamental ingredient for concrete production. However, the indiscriminate extraction of sand from riverbeds led to serious environmental issues, like erosion of riverbeds, destruction of aquatic habitats and increased susceptibility to flooding which emphasizes the necessity of finding alternate materials. Recent studies on Weathered Crystalline Rock, a soft upper layer in quarries – often discarded as waste – have shown that WCR-sand could be a viable alternative to fine-aggregates in concrete thereby alleviating the environmental impacts caused by the extraction of natural resources. Five mixes of M65 grade concrete with sand replacement of 5%, 10%, 15% and 20% with WCR-sand were prepared, cured for maximum 90 days and tested for mechanical and durability properties. Results obtained led to the conclusion that WCR-sand can be a partial replacement up to 5% – theoretically and even up to 10% practically – of sand in concrete without affecting the mechanical and durability properties. This could potentially reduce sand-mining and rock-quarrying up-to 5 to 10% which not only helps curb the depletion of natural resources, a major environmental concern today, but aids in managing waste materials from quarrying.

Resumo em Inglês:

This study delves into the utilization of advanced materials to enhance the mechanical characteristics and longevity of concrete structures, with a specific focus on the performance and design of beams composed of light gauge steel hollow sections (LGSHS) filled with steel fiber-reinforced concrete (SFRC) under flexural conditions. SFRC, known for its exceptional fire resistance, emerges as a promising alternative to Ordinary Portland Cement (OPC) in elevating concrete properties. The experimental and numerical findings consistently demonstrated a noteworthy 12% increase in maximum loading capacity, exhibiting a consistent curved trend at the moment against mid-span displacement when employing the composite material. Finite Element Analysis (FEA) modeling was used to scrutinize core concrete failure patterns, residual displacements of external metal during the load-carrying process, and load distribution patterns throughout the structural element. The infusion of SFRC into light gauge steel sections was found to enhance load-carrying capacity, ductility, and toughness. This paper scrutinizes the mechanical properties and structural behavior of LGSHS filled with SFRC, encompassing steel and concrete properties, member geometry, and response to fire exposure. The primary objective is to assess the load-deformation characteristics of rectangular hollow beams formed by concrete-filled steel tubes (CFST) filled with SFRC. The investigation aims to determine load-carrying capacity, strain, deformation capacity, ductility, and failure characteristics under ambient and elevated temperatures.

Resumo em Inglês:

This study investigates the mechanical properties of thermoplastic polyurethane (TPU) composites reinforced with multi-walled carbon nanotubes (MWCNTs) for application in athletic protective gear. The objectives were to (1) systematically evaluate the effects of MWCNT loading level and alignment on the tensile, compressive, hardness, and impact properties; (2) identify an optimal MWCNT content range for balanced enhancements; and (3) explore scalable fabrication methods. MWCNT/TPU composites with 0.5–4 wt% loading were prepared by solution mixing and compression molding. Mechanical testing revealed significant improvements, with 62 MPa tensile strength (+19%), 507 MPa modulus (+23%), and 10% higher impact energy absorption achieved at 1–4 wt% MWCNT. MWCNT alignment further enhanced the properties, while loadings above 2 wt% showed some embrittlement. Microstructural characterization evidenced good MWCNT dispersion and interfacial bonding. The results demonstrate that low MWCNT additions can substantially enhance the strength, stiffness, and impact resistance of TPU. This indicates great potential for developing advanced, lightweight athletic protective equipment like helmets and pads with improved energy absorption and durability. Future work will focus on optimizing composite processing and design for specific gear applications.

Resumo em Português:

RESUMO O bisfenol A (BPA) é utilizado como matéria prima na fabricação do plástico e apresenta-se como um desregulador endócrino. Foi realizado o desenvolvimento e a validação de um método voltamétrico para determinação de BPA e o método foi baseado em sensores descartáveis de carbono modificados com carbon black. A voltametria de onda quadrada foi selecionada para a determinação do BPA em amostras de água mineral, comercializadas em garrafas plásticas, e este método foi validado por meio das figuras de mérito. Observou-se uma resposta linear no intervalo de concentração de 6,10 a 27,4 µmol L–1, com valores de limites de detecção e de quantificação iguais a 0,137 µmol L–1 e 0,416 µmol L–1, respectivamente. O método demonstrou seletividade adequada e boa precisão, com desvios padrão relativos entre 0,59 e 9,89%, estando abaixo do limite indicado para esta faixa de concentração. A estimativa da exatidão, em termos de recuperação média, foi obtida na faixa de 58,16 e 118,79%, estando dentro dos limites estabelecidos por órgãos reguladores. Deste modo, os resultados obtidos neste trabalho são viáveis frente a outros trabalhos já reportados na literatura para a determinação de BPA, apresentando-se como uma alternativa rápida e de baixo custo para o monitoramento deste contaminante.

Resumo em Inglês:

ABSTRACT The bisphenol A (BPA) is a raw material in plastic manufacturing and is known as an endocrine disruptor. The development and validation of a voltammetric method for BPA determination were carried out, based on disposable carbon sensors modified with carbon black. Square-wave voltammetry was selected for BPA determination in mineral water samples, marketed in plastic bottles, and this method was validated using figures of merit. A linear response was observed in the concentration range of 6.10 to 27.4 µmol L–1, with detection and quantification limits values of 0.137 µmol L–1 and 0.416 µmol L–1, respectively. The method demonstrated adequate selectivity and good precision, with relative standard deviations ranging from 0.59 to 9.89%, which were below the indicated limit for this concentration range. Accuracy estimation, in terms of average recovery, ranged from 58.16 to 118.79%, falling within the limits established by regulatory agencies. Thus, the results obtained in this study are viable compared to other studies reported in the literature for BPA determination, presenting themselves as a rapid and cost-effective alternative for monitoring this contaminant.

Resumo em Inglês:

ABSTRACT Emulsified asphalt is commonly used in highway engineering as a binder for interlayer bonding, slurry seals, micro-surfacing, and cold recycled asphalt mixtures. Its storage stability is a common technical challenge in the field. The preparation process of emulsified asphalt significantly impacts its storage stability. This paper examines the effects of emulsion pH, asphalt temperature, and shearing time on the storage stability of emulsified asphalt and the particle size of asphalt droplets. The morphological evolution of asphalt droplets was observed using fluorescence microscopy, and the principles of emulsion sedimentation were elucidated. Based on this, the optimal preparation conditions for emulsified asphalt were determined using response surface methodology. The results indicate that emulsion pH, asphalt temperature, and shearing time significantly affect the particle size of emulsified asphalt droplets and their storage stability. Emulsified asphalts with a larger number of droplets and smaller particle sizes exhibit superior storage stability. Furthermore, the correlation between the D50 particle size of asphalt droplets and the storage stability of emulsified asphalt is stronger than that of D10 and D90, making D50 a more suitable indicator for predicting and assessing the storage stability of emulsified asphalt. Finally, the response surface optimization identified the optimal preparation conditions for emulsified asphalt as an emulsion pH of 3.2, an asphalt temperature of 137.3°C, and a shearing time of 74 seconds.

Resumo em Português:

RESUMO O setor da construção civil desempenha um papel fundamental no desenvolvimento social, mas é responsável pelo consumo de recursos naturais e energéticos do mundo. Portanto, as pesquisas buscam incorporar resíduos na produção de materiais, alinhando-se com metas globais de redução das emissões de CO2, descarte em aterros sanitários e extração dos recursos. Entre os resíduos industrias, destaca-se o resíduo proveniente do processo de lapidação do vidro (RLV), pouco explorado na literatura e com taxas significativas de descarte em aterros. Assim, esta pesquisa tem como objetivo avaliar as propriedades de argamassas com incorporação de RLV, em substituição parcial ao cimento Portland e ao agregado, por meio de uma investigação abrangente das propriedades do material produzido. Os materiais componentes das misturas e as argamassas foram caracterizados de acordo com as prescrições normativas. Os dados obtidos foram analisados por meio da metodologia de análise de variância (ANOVA) e teste de Tukey. Os resultados mostraram que o RLV influenciou no índice de consistência, na massa específica real e na aderência à tração das argamassas, reduziu a absorção de água, absorção por capilaridade e retração. Quanto à resistência à compressão, observou-se que até 10% pelo RLV, em substituição ao cimento, não compromete esta propriedade, havendo aumento relativo de resistência, quando em substituição à areia. Já para a durabilidade, houve uma melhoria nesta propriedade. Conclui-se que a utilização de RLV, em substituição parcial ao cimento Portland e ao agregado miúdo, na produção de argamassas é uma alternativa técnica, pois apresentou desempenho que possibilita seu uso, e atende aos princípios do desenvolvimento sustentável, os quais apresentam alternativas capazes de contribuir para a economia de energia e recursos naturais.

Resumo em Inglês:

ABSTRACT The construction sector plays a fundamental role in social development, but is responsible for the consumption of the world’s natural and energy resources. Therefore, research seeks to incorporate waste into the production of materials, aligning with global goals for reducing CO2 emissions, disposal in landfills and resource extraction. Among industrial waste, waste from the glass cutting process (GCW) stands out, little explored in the literature and with significant rates of disposal in landfills. Therefore, this research aims to evaluate the properties of mortars incorporating GCW, as a partial replacement for Portland cement and aggregate, through a comprehensive investigation of the properties of the material produced. The materials that make up the mixtures and mortars were characterized in accordance with regulatory requirements. The data obtained were analyzed using the analysis of variance (ANOVA) methodology and Tukey test. The results showed that the GCW influenced the consistency index, the specific gravity and the tensile bond strength of the mortars, reducing water absorption, capillary absorption and shrinkage. As for compressive strength, it was observed that up to 10% by GCW, replacing cement, does not compromise this property, with a relative increase in strength when replacing sand. As for durability, there was an improvement in this property. It is concluded that the use of GCW, in partial replacement of Portland cement and fine aggregate, in the production of mortars is a technical alternative, as it presented performance that enables its use, and meets the principles of sustainable development, which present capable alternatives to contribute to saving energy and natural resources.

Resumo em Inglês:

The study aims to optimize machining parameters for turning SAE 8822 Alloy steel under green machining (without coolant), using a CNC turning machine with a carbide tool. The controlled factors are spindle speed (A), feed rate (B), and depth of cut (C), with roughness (Ra) as the response variable. The experimental runs are conducted using an L9 Orthogonal Array (OA). Orthogonal arrays are used to efficiently explore the parameter space with a relatively small number of experimental runs while maintaining statistical validity. The impact of the machining parameters on the roughness is interpreted using Analysis of Variance (ANOVA). ANOVA is a statistical technique that helps identify the significance of each parameter and their interactions on the response variable. The result indicated that variation of A between 1500 rpm to 2000 rpm resulted in a significant increase in Ra. Similarly, the effect of B and C contributed towards huge variations in Ra. The optimal values of 1500 rpm for A, 0.5 mm/rev for B, and 1 mm for C are identified as the most favorable combination for achieving the desired Ra. Achieving a minimum Ra of 0.04 microns indicate a very high-quality surface, which may be desirable in precision engineering applications. The analysis shows that the C and B have the highest influence followed by A on Ra.

Resumo em Português:

ABSTRACT Population growth and the high demand for the use of wood already consolidated on the market have caused a high demand for forestry resources. This factor motivated the search for other species with properties that satisfy everyday needs in industrial applications. The research aims to characterize the physical-mechanical properties of Anthocleista grandiflora wood. Samples were taken to determine the properties of the three trunks’ base, middle, and top regions at 38, 43, and 47-year-old. Physical (density, moisture content, and volumetric increase) and mechanical tests (flexural strength, elasticity resistance, shear strength, and Janka hardness) were used to characterize the material. The results confirmed that the lowest average moisture content was presented at the base of 38-year-old trees, with values varying from 12.2 to 13.3% in the heartwood and sapwood regions. For density, the base of 47-year-old trees obtained the highest values, with a variation of 434.3–477.3 kg m–3 in the heartwood and sapwood regions. Mechanical flexural strength tests demonstrated that the highest value for the modulus of rupture was 63 MPa, indicated by samples taken from the heartwood of 43-year-old trees. The results show that A. Grandiflora wood can be used for various value-added purposes (construction, furniture, and other equipment).

Resumo em Inglês:

ABSTRACT For structural strengthening and retrofitting, advanced composite materials like carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) are frequently utilized. Applications in civil engineering require a thorough understanding of the behaviour and response of such materials. To forecast the stress-strain behaviour, the current research focuses on the numerical simulation of CFRP and GFRP-reinforced concrete specimens. ABAQUS was used to model a concrete specimen using the C3D8R solid element. The material modeling has considered the nonlinear compression behaviour of concrete and the linear elastic compression behaviour of CFRP/GFRP. The research examined gains in load-carrying capacity compared to concrete of normal strength and confined to unconfined strengths. The validity of numerical simulation has been confirmed through comparison with published experimental results. Additionally, the impact of the number of layers is carefully examined. Additionally, a comparison of the stress-strain characteristics of specimens enhanced with GFRP and CFRP has been conducted.

Resumo em Inglês:

Abstract In this work, the microstructure evolution and mechanical properties of 6201 aluminum alloy during multi-directional forging (MDF) and solution-aging were systematically studied. In the MDF process, the deformation of 6201 aluminum alloy was not uniform, and the increase of forging passes can effectively improve the inhomogeneity. With the increase of forging passes, the alloy changed from dynamic recovery to dynamic recrystallization, the grains in the center were refined obviously, and the anisotropy of microstructure was eliminated. After 9 passes of MDF followed by the solution-aging, the re-dissolution and re-precipitation behavior of the second phases significantly improved the mechanical properties of the alloy. The tensile strength, yield strength, elongation and conductivity of the alloy were 257 MPa, 139 MPa, 16.1%, 51.6% IACS, respectively, 55.8%, 73.8%, 3.4% and 10.5% higher than that of the as-cast alloy. At the same time, the average grain size of the alloy was decreased to 133 μm, 50.9% lower than that of the initial one.

Resumo em Inglês:

abstract This study presents an innovative crude oil heating technology by introducing environmentally friendly solar energy into the petroleum industry. By integrating novel combination methods into traditional crude oil heating systems, a versatile and efficient crude oil heating system has been formed. The system was implemented in a refinery and its thermodynamic and economic performance was analyzed. The thermodynamic analysis, employing the exergy analysis method, reveals that among the considered parameters, compressor pressure ratio and Rankine cycle fluid flow rate exert the most significant influence on system efficiency. Overall, the system achieves energy efficiency, exergy efficiency, and waste heat recovery efficiency of 75.99%, 74.13%, and 31.21%, respectively. Within the system, solar collectors, TES tank, and compressor exhibit the highest exergy destruction rates, while pumps demonstrate the lowest exergy destruction rate. The economic analysis, using the annualized cost method, revealed that electricity prices have a significant impact on the economic performance of the system. The variation in system economic parameters is related to the annualized operating cost of the system. The system generates a net annual benefit of 0.591 million US$, with a 4.124-year investment return period. Moreover, Sensitivity analysis explores various factors affecting the crude oil heating system’s performance.

Resumo em Inglês:

Abstract Due to collapse of buildings, the earthquakes in India and other countries have resulted in the death of people and damage to property. While it is impossible to prevent earthquakes, it is possible to lessen the damage they cause to existing structures by taking the necessary measures. It becomes crucial to perform an assessment first, then identify the weak members, and finally, carry out the necessary strengthening. Using pushover analysis, this study aims to evaluate the existing R.C. building in Zone-III. The analysis research shows the building’s performance levels, component behaviour, failure mechanism, and hinge formation. Externally wrapped GFRP sheets were used to strengthen the existing member’s deficiency.

Resumo em Português:

RESUMO Este trabalho visa analisar a evolução morfológica de uma liga comercial de alumínio A332 produzida via lingotamento contínuo convencional durante o processo de tixoconformação. A caracterização da transição sólido-líquido, ou seja, as temperaturas de trabalho correspondentes as frações sólidas de 77%, 67% e 52% foram determinadas via ensaios de análise térmica de calorimetria diferencial de varredura (DSC), na sequência a liga foi reaquecida até as temperaturas de trabalho e mantidas pelos tempos de tratamento de 0 s, 30 s e 90 s. Por meio da metalografia convencional observou-se o aumento no seu tamanho durante a manutenção da liga à faixa semissólida para o tempo de 90 s de tratamento sendo o principal mecanismo para essa alteração o fenômeno de ostwald ripening seguido por coalescência. Tem-se que a menor fração sólida proporcionou maiores valores de tamanho de glóbulos primários e de grãos, porém apresentou baixos valores de viscosidade aparente em torno de 105 Pa.s devido a menor presença de fase sólida na estrutura da liga e consequentemente menor resistência ao escoamento. Este baixo valor de viscosidade aparente torna a liga propícia a ser utilizada como matéria-prima nos processos de tixoconformação.

Resumo em Inglês:

ABSTRACT This work aims to analyze the morphological evolution of the commercial A332 aluminum alloy produced via direct casting during the thixoforming process. The characterization of the solid-liquid transition, that is, the working temperatures corresponding to the solid fractions of 77%, 67% and 52% were determined via differential scanning calorimetry (DSC) tests, then the alloy was reheated until the temperature of and maintained for 0 s, 30 s and 90 s treatment times. Through conventional metallography, an increase in the size was observed during the maintenance of the alloy to the semi-solid band for the time of 90 s of treatment being the main mechanism for this change is the phenomenon of ostwald ripening followed by coalescence. It is known that the smallest solid fraction provided higher values of size of primary globules and grains, however, it presented low values of apparent viscosity around 105 Pa.s due to the lower presence of solid phase in the alloy structure and consequently less resistance to flow. This value low apparent viscosity makes the alloy suitable for used as a raw material in thixoforming processes.

Resumo em Inglês:

ABSTRACT This study examines the effects of using crushed Printed Circuit Board (PCB) (also known as E-waste aggregate) in concrete as a partial substitute for regular coarse aggregate (NCA). M25 grade concrete was utilized. After substituting 0%, 10%, and 15% of the natural coarse aggregates with E-waste aggregate, three combinations were still complete. Verified examples continue to focus on strength attributes, after which long-lasting characteristics such as aquatic concentration, thermal expansion, and abrasion encounter tests were carried out. Test results proved that when the replacement percentage of Electronic waste aggregate was higher significant reduction in strength properties was noticed. It is container remains credited to the reality that incorporation of E-waste aggregate slows down the hydration process that would lead to a significant loss in strength. However, it was observed that mix made with 10% and 15% E-waste aggregate shows better resistance against durability properties than control mix concrete. It was also observed that utmost care should be taken for maintaining proper workability and removal of toxic substances in E-waste aggregate for better forte and toughness properties.

Resumo em Inglês:

The microstructure, mechanical properties, and heat treatment process relationships of 45MnVS non-tempered steel were investigated. Different grain sizes and tissue ratios were obtained after heating and holding at 950, 1050, and 1150 °C for 30 min, respectively, and cooling at different cooling conditions and cooling rates. As the austenitizing temperature increased, the grain size and the elongation and section shrinkage of the experimental steels decreased. At the same time, the content of ferrite and pearlite in the tissue gradually decreases, the content of sorbite and troostite rises, and the strength and hardness of the experimental steel increase. With the increase of cold speed, ferrite’s content decreases, sorbite and troostite’s content increases, and strength and hardness increase. The original austenite grain size also influences the tissue ratio. As the austenite grain refines, the ferrite transformation temperature increases during cooling and the ferrite content in the tissue rises after cooling.

Resumo em Português:

RESUMO O uso de Concreto Leve com Pérolas de EPS (CLEPE) em lajes estruturais surge como uma alternativa economicamente atrativa para reduzir o peso próprio das estruturas de concreto armado. Contudo, a modificação da massa estrutural e a substituição do agregado graúdo convencional pelo EPS impactam diretamente as propriedades dinâmicas da estrutura. Neste contexto, o objetivo deste estudo é investigar a influência da substituição do Concreto Convencional (CC) pelo CLEPE nas propriedades dinâmicas da estrutura, considerando o impacto da diminuição significativa de massa e rigidez do material. Para a determinação dos parâmetros dinâmicos, como frequências naturais, deformações modais e fatores de amortecimento, foram realizados experimentos em corpos de prova cilíndricos e lajes retangulares, empregando métodos de análise modal estocástica e ensaio dinâmico de resposta acústica. Os resultados revelam clareza nas deformações modais e uma aproximação satisfatória entre as frequências naturais experimentais e numéricas. Em relação ao fator de amortecimento, observou-se que para o CLEPE, este parâmetro é ligeiramente superior ao do CC, sugerindo uma integridade estrutural adequada das lajes. Com base nos resultados obtidos, conclui-se que, para análises individuais de elementos de CLEPE sem fissuras, é recomendável adotar um valor médio para o fator de amortecimento de 0,5%, que se mostrou superior ao valor médio correspondente ao CC ensaiado, sem fissuras, de 0,4%. No entanto, para análises estruturais globais, os valores teóricos convencionais são mais apropriados. Embora a pesquisa forneça resultados sobre o comportamento dinâmico de lajes de CLEPE, ressalta-se a necessidade de estudos adicionais em condições de fissuração para uma compreensão mais abrangente do material em situações realistas.

Resumo em Inglês:

ABSTRACT The use of Lightweight Concrete with EPS Beads (LCBE) in structural slabs emerges as an economically attractive alternative to reduce the self-weight of reinforced concrete structures. However, the modification of the structural mass and the substitution of conventional coarse aggregate by EPS directly impact the dynamic properties of the structure. In this context, the objective of this study is to investigate the influence of replacing Conventional Concrete (CC) with LCBE on the dynamic properties of the structure, considering the significant decrease in mass and stiffness of the material. For the determination of dynamic parameters such as natural frequencies, modal deformations, and damping factors, experiments were conducted on cylindrical specimens and rectangular slabs using stochastic modal analysis methods and dynamic acoustic response tests. The results reveal clarity in modal deformations and a satisfactory approximation between experimental and numerical natural frequencies. Regarding the damping factor, it was observed that for LCBE, this parameter is slightly higher than that of CC, suggesting adequate structural integrity of the slabs. Based on the obtained results, it is concluded that for individual analyses of crack-free LCBE elements, it is recommended to adopt an average value for the damping factor of 0.5%, which proved to be higher than the corresponding average value for crack-free CC tested, of 0.4%. However, for global structural analyses, conventional theoretical values are more appropriate. Although the research provides results on the dynamic behavior of LCBE slabs, the need for additional studies under cracking conditions is emphasized for a more comprehensive understanding of the material in realistic situations.

Resumo em Inglês:

ABSTRACT Coal gangue occupies substantial land resources. Using coal gangue as reinforcement fill material is an effective utilization method. The characteristics of the soil-reinforcement interface influence the safety and stability. Large-scale direct shear tests were conducted to study the interface characteristics of coal gangue with polypropylene woven geotextile, welded steel-plastic geogrid, and high-density polyethylene uniaxial geogrid. The tests revealed that the shear stress-shear displacement relationship is nonlinear and positively correlated with normal stress, with the breakage of burnt coal gangue particles observed during the process. The maximum shear stress and shear strength index of the interface for the three geosynthetics reinforced coal gangue are in the order of uniaxial high-density polyethylene (HDPE) geogrid showing the highest reinforcement strength, followed by the welded steel-plastic geogrid, with the polypropylene woven geotextile having the lowest strength. After HDPE geogrid reinforcement, interface friction angle slightly changes, but cohesion significantly increases, with an increase of 1156.9%. Considering the interface interactions, among the three geosynthetic materials, HDPE geogrid exhibits the most effective reinforcement effect on coal gangue, followed by the welded steel-plastic geogrid. The geotextile shows the least effectiveness in reinforcing burnt coal gangue. For reinforced coal gangue projects, HDPE geogrid is recommended as the reinforcing material.

Resumo em Inglês:

ABSTRACT This study assessed the properties of particleboard produced from the replacement of urea formaldehyde with cassava starch. Cassava starch (CS) and urea-formaldehyde (UF) were mixed at percentages of 100/0, 90/10, 70/30, 50/50, and 0/100, respectively. The mixture was added to the wood particles at 15% adhesive content based on the weight of oven-dried particles. Particleboards of sizes 20 mm × 300 mm × 300 mm and a targeted density of 600 kg m–3 were manufactured by hot-pressing at 170 °C, compacting pressure 3.5 MPa for 8 min. Physical and mechanical properties (density, thickness swelling, water absorption, static bending, and hardness) were tested. The physical and mechanical properties also increased in the highest proportions of UF. Comparatively, manufactured with 50% CS + 50% UF, it performed better in all the evaluated properties. Thus, it could adopt the latter mixed ratio in the industry to reduce the quantity and cost of UF and its environmental emissions. The results obtained were adequate and in conformity with international standards. Hence, it could mix cassava starch and urea formaldehyde adhesives in different ratios to get desirable properties. It is possible to conclude that cassava starch could be considered a sustainable alternative adhesive.

Resumo em Português:

RESUMO O objetivo deste trabalho foi avaliar a tixoconformabilidade da liga Al4Si2.5Cu sob duas diferentes rotas de produção: técnica via refino de grão e via agitação eletromagnética, abrangendo desde a obtenção da liga até sua caracterização microestrutural e mecânica após o processo de tixoforjamento em uma prensa excêntrica mecânica. A liga foi submetida a tratamentos térmicos de globularização que promovem a globularização das partículas de fase primária pelos tempos de 0s e 210s na fração sólida de 45% e na sequencia tixoforjada. Os ensaios de tixoforjamento mostraram que a força necessária de fechamento da matriz é praticamente constante, independentemente do tempo de globularização, ficando em torno de 70 kN, utilizando menos de um terço da capacidade da prensa. Com relação a sua morfologia para ambas as rotas de produção, a mesma apresentou morfologia globular para ambos os tempos de tratamento térmico. As peças tixoforjadas apresentaram boa conformabilidade preenchendo toda a matriz e reproduzindo sua geometria, além de apresentar boas propriedades mecânicas nos ensaios de tração, ou seja, o valor limite de resistência à tração principalmente quando utilizado a rota de produção via agitação eletromagnética apresentou valores próximos a 200 MPa. Demonstrando que a liga torna-se propicia aos processos de tixoconformação.

Resumo em Inglês:

ABSTRACT The objective of this work was to evaluate the thixoformability of the Al4Si2.5Cu alloy under two different production routes: the techniques via grain refining and via electromagnetic stirring, ranging from obtaining the alloy to its microstructural and mechanical characterization after the thixoforging process in a mechanical eccentric press. The alloy was subjected to globularization heat treatments promoting the globularization of the primary phase particles for 0s and 210s in the 45% solid fraction and the thixoforged sequence. The thixoforging tests showed that the necessary force to close the die is practically constant, regardless of the globularization time, remaining around 70 kN, using less than a third of the press capacity. Regarding its morphology for both production routes, it presented a globular morphology for both heat treatment times. The thixoforged parts showed good formability, filling the entire matrix and reproducing its geometry, in addition to presenting good mechanical properties through tensile tests, that is, the limit value of tensile strength, especially when using the production route via electromagnetic stirring, presented values close to at 200 MPa. It demonstrates that the alloy becomes suitable for thixoforming processes.

Resumo em Inglês:

ABSTRACT Mineral flotation is a wet concentration operation that has a differentiating effect dependent on the surface properties of the minerals. Water quality is integral to the phosphate ore flotation, since the presence of certain ions in the solution can compromise the effectiveness of the operation. The objective of this study was to compare the effectiveness of phosphate ore flotation (dispersed air) before and after effluent treatment using coagulation, flocculation and dissolved air flotation (DAF) techniques. The mineral flotation tests were performed for new water (NW) and three effluents tailing dams (TD), simulated effluent with high concentrations of calcium and magnesium ions (SE) and simulated effluent after DAF treatment (SEDAF). The simulated effluent underwent two stages of aggregation followed by DAF for cation removal. The results showed that the proposed technique removed 91.6% of magnesium and 66.4% of calcium from the original simulated effluent (SE). The SEDAF presented better average values of mass recovery, content, and recovery of P2O5, confirming the effectiveness of the removing ions suggested as deleterious for mineral flotation. The flotation performance of the DAF-treated effluent was comparable to that of new water. This study underscores the significance of water quality management in optimizing mineral flotation processes.

Resumo em Inglês:

ABSTRACT The AA 3104 aluminum alloy is widely used as packaging for food storage. However, the package fabrication causes wear to the cutting knife and stamping tools. The objective of this work was to evaluate the wear resistance of the 1020 steel applied in tools for molding and cutting operations of AA 3104, with and without surface treatment, comparing two techniques of wear tests. The samples of 1020 steel were treated by plasma nitriding and DLC film deposition. All samples were tested by a microwear test by fixed ball (MWT). Also, a prototype of the tools machine was developed to simulate the wear between 1020 steel against AA 3104 that occurs in service, whose wear result was analyzed by the moiré optical technique by phase-shifting (DWT). It was observed that the treated samples increased the wear resistance compared to the base material (BM), indicating an increase in the cutting tool lifetime. The DLC film treatment presented greater wear resistance than the nitriding treatment. The microwear test presented the wear volume behavior similar to the behavior of the prototype of wear test, showing that the MWT can be used to study the wear phenomenon with good relationship with the practice, the DWT can indicate the wear behavior of the material in service and the moiré technique can be efficiently used to determine a wear behavior in the designed wear test.

Resumo em Inglês:

ABSTRACT Many dilapidated civil constructions have been demolished as a result of the necessity for rehabilitation and the effective use of the land that is available. The build-up of waste materials from destroyed concrete strains landfills and adds to the environmental load, making development initiatives unfeasible. Superplasticizers can be used to improve the mechanical characteristics of concrete, which is one way to address this problem. The objective of this work is to assess how a superplasticizer affects the mechanical characteristics of concrete made using recycled aggregate. In order to make concrete specimens, several replacement ratios of fresh natural aggregates with recycled stone and brick aggregates were tested, ranging from 0% to 100%. After applying the superplasticizer to 50% of the concrete specimens, the water content of the concrete mixtures decreased by 15%. The outcomes of the tests show that adding superplasticizers to recycled aggregate concrete improves its mechanical qualities. The mechanical performance of the concrete was found to be unaffected by the addition of superplasticizer, even when recovered stone and brick aggregates replace 50% and 25% of the fresh, natural coarse aggregates, respectively.

Resumo em Inglês:

Abstract In this study, first of all, single jersey fabric scraps knitted from Ne 30/1 (19.7 Tex) cotton yarns were obtained. These scraps were recycled in the rag puller machine without mixing with any other products. Yarn production from recycled fibers was made by open-end spinning machine and Ne 30/1 yarns were systematically produced again. By comparing the test results of the initial state of the yarns and the test results after the recycling process, the impacts of the recycling process of the single jersey fabric knitted from Ne 30/1 cotton yarns on the yarn performance properties were presented objectively. Yarn unevenness of the recycled yarns increased due to the decrease in fiber lengths due to the damage given to the fibers during mechanical recycling.

Resumo em Inglês:

ABSTRACT This extensive research project investigates the innovative use of electronic plastic waste, referred to as e-plastic, as an additional component in the production of concrete. This transition from an informal sector to a more structured and regulated system is vital not only for addressing the growing problem of E-waste but also for environmental preservation. To accomplish this goal, the study collected and employed waste E-plastic particles obtained from obsolete electronic devices. The research primarily concentrated on conducting a comprehensive analysis of the mechanical, durability properties and micro properties (XRD) of concrete specimens containing varying proportions of waste E-plastic, ranging from 4% to 24%. Additionally, the study introduced a modification by substituting a portion of the cement with fly ash, amounting to 10% of the total weight, with the aim of improving the overall characteristics and performance of the E-plastic-infused concrete. These experiments were carried out to gain a more holistic understanding of the concrete’s behavior, encompassing both its structural integrity and overall performance characteristics. This research significantly enhances the concrete’s workability, mechanical strength, and durability properties.

Resumo em Português:

RESUMO Embalagens cartonadas pós-consumo têm potencial para serem utilizadas como matéria-prima na fabricação de novos produtos. Esta pesquisa analisou o desempenho da substituição parcial de agregado miúdo por Resíduos de Embalagens Cartonadas em Pó (RECP) no desenvolvimento de argamassas por meio da coleta, preparo e moagem de embalagens cartonadas, bem como a caracterização de matérias-primas. Foram definidas composições de referência e experimentais, seguidas da execução de testes tecnológicos e análise dos resultados. Técnicas de Fluorescência de Raios X (XRF) e Microscopia Eletrônica de Varredura (MEV) foram utilizadas para caracterizar o subproduto, RECP, por meio de análise química. Foi adotada uma relação de referência de 1:6 entre o volume de cimento e agregado miúdo no traço de referência, enquanto as Composições Experimentais foram determinadas com substituições de 5%, 10% e 15% do volume de agregado por RECP. Estas composições foram moldadas e testadas utilizando cinco corpos de prova cilíndricos por composição. O material produzido apresentou consistência dentro dos parâmetros normativos. As resistências das três composições com reposição ficaram na faixa de 7,57 MPa, 6,52 MPa e 6,07 MPa, respectivamente. A absorção de água por imersão apresentou resultados satisfatórios. A análise por MEV das superfícies fraturadas revelou a presença de espaços vazios e microfissuras nas amostras com maiores percentuais de RECP.

Resumo em Inglês:

ABSTRACT Post-consumer carton packaging has the potential to be utilized as raw material in the manufacturing of new products. This research analyzed the performance of partially replacing fine aggregate with Powdered Carton Packaging Waste (PCPW) in mortar development through of collection, preparation, and milling of carton packaging, as well as the characterization of raw materials. Reference and experimental compositions were defined, followed by the execution of technological tests and analysis of the results. X-Ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) were used to characterize the by-product, PCPW, through chemical analysis. A reference ratio of 1:6 between the volume of cement and fine aggregate was adopted, while Experimental Compositions were determined with substitutions of 5%, 10%, and 15% of the aggregate volume with PCPW. These compositions were molded and tested using five cylindrical specimens per composition. The produced material exhibited consistency within normative parameters. The strengths of the three compositions with replacement fell within the range of 7.57 MPa, 6.52 MPa, and 6.07 MPa, respectively. Water Absorption by Immersion showed satisfactory results. SEM analysis of the fractured surfaces revealed the presence of empty spaces and microfissures in the samples with the highest percentages of PCPW.

Resumo em Inglês:

ABSTRACTIn this study, the mortars utilized in the restoration projects need to be compatible with the conventional materials that were first used in these structures, both in terms of their mechanical and physiochemical qualities. Here, varying proportions of tufa stone powder – 37 and 42 percent by weight of the mixture, are used to partially replace the fine aggregate mixed mortars for repairs (M1, M2). In order to compare the performance of the third type of mortar (M3) with the tufa stone-based combinations, it was used in addition to the previously made mortars (M1, M2). The three types of mortars were thoroughly evaluated by examining their mechanical properties and durability qualities in conjunction with the tufa stone. The prepared mortar M2, out of all the mortars tested, which had a higher percentage of tufa stone powder substitution and a lower binder content, performed the worst mechanically, according to the data. The compressive and flexural strength of M2 mortar mix is 1.12 MPa and 0.72 MPa tested at 28 days. Similarly, the UPV, shear strength and shear interface for the M2 mortar mix is 0.71 MPa, 0.52 MPa and 1208 m/s at 60 days respectively. This implies that in comparison to the traditional tufa masonry, this specific mortar is less compact and more flexible. The created mortar (M2) has similar thermal qualities and is long-lasting like tufa stone found in historical sites.

Resumo em Inglês:

Abstract Grain boundaries are fundamental in the mechanical behavior of ultrafine grain materials, especially coincidence site lattice grain boundaries (CSL-GB). This research aims to identify the influence of CSL-GB on the hardness and electrical conductivity of a CuCrZr alloy subjected to rotary swaging after having undergone severe plastic deformation via equal channel angular pressing and aging. Vickers hardness was evaluated, and electrical conductivity was measured using the 4-point technique. The average grain size and CSL-GB distribution were identified using backscattered electron diffraction. Dislocation density was measured via X-ray diffraction. At the end of the swaging processing of CuCrZr alloy with preexistent ultrafine grains, the dislocation density ceases to be the significant influencer parameter on the modification of properties, and the grain boundaries pass to be more impacting. The reduction of CSL-GB and the concomitant increase in high-angle grain boundaries can decrease hardness and electrical conductivity.

Resumo em Inglês:

ABSTRACT The construction of shield machines will confront complex geological types, to solve the safety problem caused by the material toughness of plastic drainage boards (also known as PVD) during shield tunneling, a new type of shield machine cutter for breaking plastic drainage board is proposed in this paper. Firstly, a mechanical model of the interaction between the cutter and the material is established, calculation analysis and comparison are carried out. Then, the cutting ability of the new cutter on drainage board under different conditions is tested, and corresponding experimental data are obtained, verifying the advantage of the new cutter proposed in this paper. The finite element analysis software LS-DYNA is used for simulation and based on a plastic drainage board cutting project in Singapore, an experiment platform for shield machine cutter to break plastic drainage board is designed to conduct experiments. This work will provide technical guidance for the material cutting engineering of actual drainage boards.

Resumo em Português:

RESUMO No setor automotivo as ligas de alumínio têm se destacado por sua atraente combinação entre resistência/peso, entre outras características. As ligas da série 5XXX tem seu ganho de resistência mecânica através de processos de deformação a frio, e as propriedades mecânicas das ligas de alumínio estão diretamente relacionadas à sua composição e ao processo de fabricação utilizado em sua manufatura. Um dos requisitos para otimizar as operações de conformação mecânica é o controle da microestrutura e textura. Neste trabalho, as ligas AA 5052 e AA 5050C, produzidas por Fundição Direta (Direct Chill – DC), e Fundição Contínua de Chapas (Twin Roll Caster – TRC), respectivamente, passaram por caracterização mecânica via ensaio de tração (com corpos de provas extraídos a 0, 45 e 90° da direção de laminação) e caracterização estrutural e textura ao longo da espessura de chapas. Foram detectadas inclusões de alumina (Al2O3) e precipitados intermetálicos de Al3Fe juntos à matriz metálica e ambas as ligas apresentam as componentes cobre (112)[111¯], latão (“Brass”) {110}<112>, cubo (001)[010¯] e Goss {110}<001>, ao longo da espessura. A liga AA 5052 apresentou valores de coeficiente de anisotropia planar e normal superiores aos da liga AA 5050C, como também as propriedades mecânicas medidas em tração uniaxial.

Resumo em Inglês:

ABSTRACT In the automotive sector, aluminum alloys have stood out for their attractive combination of strength-to-weight ratio, among other characteristics. The 5XXX series alloys mechanical properties are related to their composition and the manufacturing process used, gaining most of their mechanical strength through cold deformation processes. One of the requirements to optimize mechanical forming operations is the microstructure and texture control. In this study, AA 5052 and AA 5050C alloys, produced by Direct Chill (DC) casting and Twin Roll Caster (TRC), respectively, underwent mechanical characterization through tensile testing (with specimens extracted at 0, 45, and 90° from the rolling direction); and microstructural and texture characterization across the thickness of the sheets. Alumina (Al2O3) inclusions and intermetallic precipitates of Al3Fe were detected along the metallic matrix of both alloys, exhibiting components of copper (112)[111¯], brass {110}<112>, cube (001)[010¯], and Goss {110}<001> throughout the thickness. AA 5052 alloy showed higher planar and normal anisotropy values than AA 5050C alloy, as well as mechanical properties measured in uniaxial tension.

Resumo em Inglês:

abstract The switched reluctance motor (SRM) plays a significant role in many industrial applications. Among the various topologies of SRM, modified segmented rotor SRM (MSRSRM) overcomes the shortfalls of conventional SRM. From an application perspective, the analysis of electromagnetic and thermal aspects of segmented rotor SRM becomes crucial. In the present work, the thermal analysis for modified segmented rotor SRM used in cooling fan applications is detailed. The effect of temperature rises in the different parts of the machine due to electromagnetic losses is identified by using the finite element software package ANSYS. External fin-based convective cooling strategy is adopted and analysed for the MSRSRM proposed in the present work. Choosing the suitable fin material and arrangements of fins play a crucial role in the effective thermal management of the MSRSRM. Three different Aluminium (Al) Metal Matrix Composites (MMC) based fins are considered for this analysis. In addition, the optimum number of fins and their thickness are also identified using thermal analysis. The results revealed that the Al/Diamond MMC-based fins are more effective compared with other fin materials. Also, the axial type-thin fin (1mm) arrangement yields better results compared with other fin arrangements.

Resumo em Português:

RESUMO A ampla adoção de aço galvanizado no segmento industrial, como a indústria automotiva, baseia-se em ótimas propriedades em conferir durabilidade aos produtos manufaturados, além de reduzir impactos ambientais e custos na cadeia produtiva, evitando-se corrosão e conferindo maior vida útil devido a camada protetora de zinco. Porém, essa camada quando submetida a processo de soldagem implica potenciais defeitos devido à evaporação de vapor de zinco e fragilidade do metal líquido durante a soldagem, com potencial geração de porosidade, falta de penetração ou fusão. Em última instância, esses defeitos podem trazer impactos significativos na redução de propriedades mecânicas, trincas e fraturas nas juntas soldadas. Neste trabalho, essas implicações são analisadas através das características microestruturais e propriedades mecânicas de juntas soldadas com aço galvanizado ZAR230 pelos processos de soldagem GMAW e FCAW, avaliando-se fatores mais amplamente modificados em escala industrial nessa técnica de soldagem: o tipo de metal de adição, sendo ele arame sólido ou tubulares – autoprotegido com proteção gasosa e sem proteção gasosa, e o tipo de gás de proteção (com misturas de 92% Ar + 8% CO2, e 95% Ar + 5% O2). Utilizando-se de técnicas de microscopia ótica de varredura, metalografia, ensaios de tração e microdureza, os resultados apontam que todas as condições testadas possuem propriedades mecânicas de dureza e tração aceitáveis, com variação de presença de defeitos, inclusões e aspecto de cordão, sendo a melhor combinação a de uso do arame sólido com mistura 92% Ar + 8% CO2.

Resumo em Inglês:

ABSTRACT The wide adoption of galvanized steel in the industrial segment, such as the automotive industry, is based on excellent properties in providing durability and weight reduction to manufactured products, in addition to reducing environmental impacts and costs in the production chain, avoiding corrosion, and providing longer lifecycle useful due to the protective zinc layer. However, this layer when submitted to the welding process implies potential defects due to evaporation of zinc vapor and fragility of the liquid metal during welding, with potential generation of porosity, lack of penetration or melting. Ultimately, these defects can significantly impact the reduction of mechanical properties, cracks, and fractures in welded joints. In this work these implications are analyzed through the microstructural characteristics of joints welded with ZAR230 galvanized steel by the GMAW and FCAW welding processes, evaluating the mostly common factors that are modified on an industrial scale in this welding technique: the type of filler metal, whether solid wire or tubular – self-protected with gas protection and without gas protection, and the type of protection gas (with mixtures of 92% Ar + 8% CO2, 80% Ar + 20% CO2 and 95% Ar + 5% O2). Using scanning optical microscopy techniques, metallography, tensile tests and microhardness, the results indicate that all tested conditions have acceptable mechanical properties of hardness and traction, with variation in the presence of defects, inclusions and welding bead, with the best combination being the use of solid wire with mixture 92% Ar + 8% CO2.

Resumo em Inglês:

ABSTRACT Cenosphere is a captivating material in the realm of cementitious materials. Its unique properties, such as being superfine, spherical, and hollow, make it a suitable additive in concrete. Fine cenosphere particles can efficiently bridge the gap among the cement particles. This increases the density and reduces porosity, thereby enhancing the performance of the concrete. The experimental results suggest that incorporating cenosphere up to 15% can lead to notable improvements in the properties of the concrete. This optimal content ensures the enhancements without detriment to the other significant characteristics of concrete. In the present scenario, cenospheres offer a sustainable solution for enlightening the characteristics of cement paste and reducing the environmental footprint of waste accumulation.

Resumo em Inglês:

ABSTRACT The study encompasses various infrastructural amenities such as railways, roads, ports, bridges, tunnels, power plants, hospitals, municipal buildings, and other public-use facilities, which are essential for every country’s economic growth. Recognizing the challenges faced by governments in independently providing all infrastructure components, Public Private Partnerships [PPPs] have emerged as a cooperative approach between the public and private sectors. This paper explores the risks, delays, key success factors, contractor selection, and best value selection models in construction project management. In addition, the paper emphasizes the challenges that governments need to address in order to ensure the efficient functioning of the BOT (Built Operate Transfer) network. The challenges in establishing an efficient BOT network are highlighted, and a decision-support system using the .Net framework is developed to aid in the prequalification and rating of BOT marketers. The purpose of this system is to provide the best value to the public procurer by employing regression analysis to rate bidders/applicants and utilizing a composite programming method based on relative weighting.

Resumo em Inglês:

ABSTRACT To address the issue of corrosive wear resulting from the addition of desulphurization wastewater into the wet slag removal system, this study investigated the corrosive wear behavior of chain steel (specifically 17NiCrMo6 steel) in desulphurization wastewater with varying chloride concentrations. Weight loss, micro-phase characterization, and electrochemical testing methods were employed for analysis. The findings indicate that as the chloride concentration increases, the weight loss rates for both pure corrosion and corrosive wear exhibit a pattern of initial increase, followed by a decrease, and then another increase. This trend can be attributed to the fact that as the chloride concentration rises, the corrosion products become denser, thereby increasing the difficulty of the corrosion reaction.

Resumo em Inglês:

ABSTRACT Many of the existing reinforced concrete structures throughout the world are in urgent need of rehabilitation, repair, or reconstruction. Because of deterioration due to various factors like corrosion, lack of detailing the failure of bonding between beam, column joints, accidental fire, loss of strength, deflection, etc. Use of externally bonded FRP for strengthening the structures has received considerable attention in recent years. This study exclusively focuses on assessing the load-carrying capacity of fire-damaged Cement and Geopolymer Concrete structural elements wrapped with BFRP laminates. And the scope of this study is expected to provide cost-effective and retrofit solutions that can be implemented in the concrete industry. The slab specimens were subjected to temperatures of 200, 400, 600 and 800°C for a period of 1, 2, and 3 hours followed by retrofitting with BFRP laminate. The results showed that the ultimate load-carrying capacity of both cement and geopolymer concrete slabs increased when exposed to 200ºC for 1 hour. However, beyond this point, the capacity started to decrease. Nevertheless, a decline in ultimate load capacity was noted for higher temperature ranges and prolonged fire exposure durations. The application of Basalt FRP wrapping to the soffit of slabs led to an 80% increase in the ultimate load capacity of both cement and geopolymer concrete slabs that had been damaged by fire. The analysis of test data led to the conclusion that retrofitting with Basalt FRP Laminates achieved a strengthening effect on the fire-damaged cement and geopolymer concrete slabs.

Resumo em Inglês:

ABSTRACT Since fiber-reinforced polymer (FRP) composites are superior to traditional steel reinforcements, they are widely used in advanced concrete technology. By using a combination of fibres and FRP strengthening techniques, RC beams can have increased strength and ductility. The kind, arrangement, composition, and strengthening method of the fibres in FRP composites in reinforced concrete beams regulate their total strength. Shear deficient specimens were strengthened by using glass and basalt fibre wrapping. Twelve beams were fabricated and tested under the static and cyclic loads. The main objective of the study is to obtain compressive and flexural behaviour from the shear deficient RC beams. This study evaluates the performance of Reinforced Concrete (RC) beams enhanced in shear using basalt fibre and glass fibre. After curing the beams were wrapped with fibres other than the conventional. All the 12 beams were tested under the same loading condition with the four point loading. The shear deficient RC beams do not have required shear reinforcement and hence they fail by shear first. FRP strengthening in the shear zones can increase the shear strength of the beams and hence these strengthened beams fail in flexure first or sometimes as flexure-shear failure.

Resumo em Inglês:

ABSTRACT Fire is considered one of the most serious potential risks for buildings and structures, as was demonstrated in the 9/11 twin tower failure. If a structure is damaged by fire, it is necessary to investigate the cause of the fire and evaluate the reusability of the damaged structure. Concrete structures often collapse in fire due to material degradation and thermal expansion. Geopolymer concrete has the potential to reduce carbon emission globally and lead to sustainable development to form an important contributor towards environmentally sustainable construction and building products industry. It proposed to be a more eco-friendly replacement to Portland cement. The experimental results of Cement and Geopolymer concrete slabs subjected to high temperatures are presented in this study. This study exclusively focuses on assessing the load-carrying capacity of fire-damaged Cement and Geopolymer Concrete structural elements. The slab specimens were subjected to temperatures of 200, 400, 600 and 800°C for a period of 1, 2, and 3 hours. The results showed that the ultimate load-carrying capacity of both cement and geopolymer concrete slabs increased when exposed to 200ºC for 1 hour. However, beyond this point, the capacity started to decrease. Nevertheless, a decline in ultimate load capacity was noted for higher temperature ranges and prolonged fire exposure durations. When exposed to high temperature, the chemical composition and physical structure of the geopolymer concrete change considerably.

Resumo em Inglês:

ABSTRACT Eco friendly manner fly ash management and utilization is the need of the hour and one of the possible ways of using it is by fabrication of interlocking bricks out of it. This research focus on the development of interlocking brick machine and bricks manufactured is tested for dimension stability, water absorption, compressibility strength and efflorescence test. The machine setup was successfully fabricated and used for production of interlocking flyash bricks. The setup mainly consists of machine structure, hydraulic system and pan mixer. Two varieties of interlocking bricks were produced with the size of 12” × 6” × 5” and 12” × 8” × 5”. Based on the results of the test the interlocking bricks are found suitable for better replacement of the ordinary bricks.

Resumo em Português:

RESUMO O Brasil se destaca como um dos maiores produtores de minérios do mundo. No entanto, essa atividade tão importante economicamente também acarreta danos significativos ao meio ambiente. O problema da disposição dos rejeitos de mineração em barragens ganhou grande repercussão após os desastres em Mariana, em 2015, e Brumadinho, em 2019, que evidenciou a necessidade de encontrar um novo uso para esses materiais. A pesquisa teve como principal objetivo avaliar a adição de rejeitos de minério de ferro em materiais utilizados nas camadas de pavimentos rodoviários, na produção de solo-cimento. Os resultados dos ensaios mecânicos mostraram que é tecnicamente viável adicionar rejeito de minério de ferro nas misturas de solo-cimento, sendo que, para camada de base, foi encontrado o teor mínimo de 6% de cimento, e de 5% e 4% para a camada de sub-base. Isso indica que o rejeito pode ser uma excelente alternativa para reduzir o consumo de cimento. Além disso, essa incorporação poderia reduzir o consumo de recursos naturais, oferecer um destino alternativo para os rejeitos de mineração e até mesmo diminuir os custos das obras de pavimentação. Com essa pesquisa, busca-se uma solução inteligente e sustentável para os impactos causados pelos rejeitos de mineração no Brasil.

Resumo em Inglês:

ABSTRACT Brazil stands out as one of the largest mineral producers in the world. However, this economically important activity also causes significant damage to the environment. The disposal of mining waste in dams gained great repercussions after the disasters in Mariana, in 2015, and Brumadinho, in 2019, that the need to find a new use for these materials arose. The main objective of the research was to evaluate the addition of iron ore waste to materials used in the base and sub-base layers of road pavements. The results of the mechanical tests demonstrated that it is technically feasible to introduce iron ore waste into the soil-cement mixtures used in the base and sub-base layers. It was found that a minimum of 6% cement in soil-cement mixtures for the base layer, and 5% and 4% for the sub-base layer, are sufficient for the addition of waste. This indicates that waste can be an excellent alternative to reduce cement consumption. This incorporation could reduce the consumption of natural resources, offer an alternative destination for mining waste and even reduce the costs of paving works. With this research, we seek an intelligent and sustainable solution to the impacts caused by mining tailings in Brazil.

Resumo em Inglês:

Abstract The potential of Portland Slag Cement (PSC) may increase mechanical strength and longevity, its application in concrete is becoming more and more popular. PSC-concrete qualities are examined in this work, with a particular emphasis on microstructure, strength, and durability. Compressive, split tensile, flexural, and modulus of elasticity tests were conducted using different curing techniques. The outcomes were contrasted with formulations of regular Portland cement (OPC). At various curing times, tests for durability such as porosity, acid resistance, sorptivity, water absorption, and chloride penetration were carried out. PSC-related microstructure alterations were examined using sophisticated methods including SEM and XRD. Results show that PSC enhances concrete performance over the short and long terms, especially in abrasive settings. Microstructural research reveals that the effect of slag is responsible for improved pozzolanic reactions, decreased porosity, and refined pore structure. The potential of PSC to improve the lifetime and durability of concrete is highlighted by this study.

Resumo em Inglês:

ABSTRACT In the aeronautical industry, 2024 aluminum alloys are widely used due to their excellent mechanical resistance and low specific mass. However, pitting formation is usual for these metal surfaces in certain corrosive environments, requiring treatment methods to protect them. Polypyrrole is a conductive polymer that has been studied for the protection of oxidizable metals against corrosion, as a viable alternative to toxic compounds. In this context, this study aims to investigate the performance of polypyrrole bilayers, electrodeposited in aqueous medium to protect 2024 aluminum alloy against corrosion. Potentiodynamic polarization curves, in corrosive chloride medium, indicated that the corrosion potential values were shifted towards the more positive values for the aluminum surfaces coated with polypyrrole films in relation to the surface of the metal just polished, indicating anodic protection. Furthermore, the Tafel curves indicated that the anodic current densities were lower for the polypyrrole bilayer electrodeposited in phosphoric acid and dodecylbenzenesulfonic acid, respectively. The morphology of the surfaces was investigated by Scanning Electron Microscopy and indicated that the bilayers were compact and homogeneous and that they were not damaged even after three days of immersion in chloride medium, indicating that the polymeric film can protect the metal against corrosion.

Resumo em Inglês:

ABSTRACT In the aeronautical industry, 2024 aluminum alloys are widely used due to their excellent mechanical resistance and low specific mass. However, pitting formation is usual for these metal surfaces in certain corrosive environments, requiring treatment methods to protect them. Polypyrrole is a conductive polymer that has been studied for the protection of oxidizable metals against corrosion, as a viable alternative to toxic compounds. In this context, this study aims to investigate the performance of polypyrrole bilayers, electrodeposited in aqueous medium to protect 2024 aluminum alloy against corrosion. Potentiodynamic polarization curves, in corrosive chloride medium, indicated that the corrosion potential values were shifted towards the more positive values for the aluminum surfaces coated with polypyrrole films in relation to the surface of the metal just polished, indicating anodic protection. Furthermore, the Tafel curves indicated that the anodic current densities were lower for the polypyrrole bilayer electrodeposited in phosphoric acid and dodecylbenzenesulfonic acid, respectively. The morphology of the surfaces was investigated by Scanning Electron Microscopy and indicated that the bilayers were compact and homogeneous and that they were not damaged even after three days of immersion in chloride medium, indicating that the polymeric film can protect the metal against corrosion.

Resumo em Inglês:

Abstract Self healing concrete structures have been considered in recent decades due to their potential to repair cracks in an efficient manner. The current study considers three different biomaterials namely Bacillus subtilis, Bacillus Flexus and Bacillus Licheniformis to be mixed with concrete at fresh state to evaluate compression strength after 7, 14 and 21 days of curing in water medium. The cracked specimens are further allowed to cure in open atmosphere for 12 days to evaluate crack healing and post healed compression strength. Taguchi full factorial experimental design has been adopted for conducting experimental trials and experimental results has been analysed using signal to noise ratio method, desirability function analysis through Mini tab 17.0. In case of initial compression strength, Bacillus subtilis mixed concrete cube specimen cured for 7 days exhibited lowest value of 70 MPa and attained 260% (252 MPa) improvement when cured for 21 days, but opposite trend is observed for final compression strength. The optimum biomaterial and curing duration for pre and post compression strength has been determined using decision tree algorithm. The recommended combination of input factors and significant influencing factor identified from both the analysis methods are in good agreement.

Resumo em Português:

RESUMO A resistência à compressão do concreto (fck) geralmente é estimulada pelo ensaio de compressão axial, sendo os métodos não destrutivos apontados como segunda opção. O objetivo do estudo é avaliar a qualidade do concreto através de ensaios ultrassônicos e esclerométricos, correlacionando-os ao método de compressão axial. Foram realizados 60 corpos de prova de concreto com idades de 7, 14 e 28 dias. Os resultados dos ensaios de ultrassom apresentaram maior dispersão para 7 dias de idade, possivelmente devido ao seu estágio inicial de cura. Com o avanço da cura, a precisão do ensaio de ultrassom melhorou significativamente, especialmente aos 28 dias. Pode-se afirmar, com 95% de confiança, que resultados de velocidade de propagação de onda acima de 4550 m/s representam resistência à compressão característica superiores a 25 MPa e resistência média superior a 30 MPa. No ensaio de esclerometria, os resultados indicaram resistências superiores às obtidas no ensaio de compressão axial. Para resultados de resistência característica à compressão esclerométrica superior a 38 MPa, os resultados do fckk esperados são de 25 MPa, com 95% de confiança. Concluiu-se que os resultados deste estudo apontam para a existência de uma correlação eficaz entre a resistência à compressão obtida nos ensaios distintos.

Resumo em Inglês:

ABSTRACT Concrete compressive strength (fck) is generally estimated by the axial compression test, with non-destructive methods considered as a second option. The objective of the study is to evaluate the quality of concrete through ultrasonic and sclerometric tests, correlating them with the axial compression method. 60 concrete specimens aged 7, 14 and 28 days were made. The results of the ultrasound tests showed greater dispersion for 7 days of age, possibly due to its initial stage of healing. As healing progressed, the accuracy of the ultrasound assay improved significantly, especially at 28 days. It can be stated, with 95% confidence, that for wave propagation speed results above 4550 m/s, they represent characteristic compressive strength greater than 25 MPa and average resistance greater than 30 MPa. In the sclerometry test, the results indicated higher characteristic resistances than those obtained in the axial compression test. For sclerometric compression strength results greater than 38 MPa, the expected fck results are 25 MPa, with 95% confidence. It was concluded that the results of this study point to the existence of an effective correlation between the compressive strength obtained in the different tests.

Resumo em Inglês:

ABSTRACT This paper evaluates the mechanical behavior of nanocarbon modified asphalt binder. The nanocarbon was produced by a pyrolysis process of lignin. Three samples of asphalt binder were used as base for modification, a Pen 30/45, a Pen 50/70, and a SBS-polymer-modified 55/75. Different conditions of temperature, stirring speed, and modification time periods were evaluated to identify the best operational conditions. The characterization of nanocarbon was performed by different methodologies. Performance tests were conducted in a dynamic shear rheometer (DSR) to determine dynamic shear modulus, phase angle, and parameters of the Linear Amplitude Sweep test (LAS) and Multiple Stress Creep and Recovery test (MSCR) on the modified and unmodified asphalt samples. Furthermore, tests were performed in a bending beam rheometer (BBR) to measure the flexural creep stiffness and m-value at low temperatures, as well as the ∆Tc parameter. The samples were submitted to short- and long-term aging, and then master curves were constructed from frequency sweep dynamical shear tests. The results indicated that small amounts (0.02% to 0.05%, w/w) of nanocarbon adopted in the research were enough to improve rutting, fatigue, and aging resistance. Finally, the results also revealed that the modified asphalt 55/75 was better homogenized with the nanocarbon than the neat asphalt cements 30/45 and 50/70.

Resumo em Inglês:

This study delves into the impact of Pseudomonas Aeruginosa bacterial additives on Conventional Concrete (CC) mixes. Four concrete blends (M1-M4) with varying bacterial cell concentrations 104, 105 and 106 underwent comprehensive analysis to evaluate their strength, durability, workability, and porosity across different curing periods. The research uncovered a consistent enhancement in mechanical properties as bacterial concentrations increased. Notably, compressive, split tensile, and flexural strengths exhibited significant improvements with elevated bacterial cell concentrations, attributed to enhanced cement hydration and mineral precipitation facilitated by bacterial activity. Impact strength tests showcased an enhanced resistance to cracking under impact loads, indicative of improved toughness in bacterial-incorporated mixes. Moreover, porosity tests revealed diminished porosity levels with bacterial incorporation, implying the gradual densification of the concrete structure over time. These findings highlight the promising potential of bacterial concrete for generating high-performance and sustainable construction materials. By harnessing bacterial bio-mineralization capabilities, the construction industry may unlock avenues to enhance concrete properties while simultaneously mitigating environmental impact.

Resumo em Inglês:

Steel and cement production emits CO2, spurring research for alternatives. Concrete materials are studied for shortages and enhancement. Construction, especially steel structures, will grow, but costs and shortages loom. Developing countries face steel scarcity and higher costs. Researchers explore natural or synthetic fiber replacements for steel, with bamboo showing promise. This study examines bamboo, with and without epoxy coating, as a steel substitute. Bamboo can replace steel in small or non-critical structures. The article explores bamboo's properties and behavior in reinforced concrete. Treating bamboo is vital for bond strength and flexural behavior under static loads. Three coatings are tested: natural, epoxy-coated, and epoxy with sand-coated bamboo. Twelve slab specimens are tested per Indian standards against steel-reinforced concrete slabs. The study evaluates bond strength, flexural behavior, and crack resistance using ultrasonic pulse velocity tests. Epoxy and sand-coated bamboo show significant improvement in bond strength, flexural performance, and concrete quality.

Resumo em Inglês:

ABSTRACT Recent years have seen a rise in both concrete costs and environmental impact. M-sand containing coconut and jute fibers was used in traditional concrete. This study explores the potential of eco-friendly coir and jute fibers as a sustainable alternative to conventional fiber reinforcement in concrete production. The coconut and jute-fiber concretes are made using a set percentage (0.5%) of the volume’s total weight of concrete. 18 cube and 18 prism specimens in total are cast and evaluated. Each type of fibre reinforced concrete specimens such as Jute fibre reinforced concrete mix (CMJF) and coconut fibre concrete mix (CMCF) contains 0.5% of the volume’s total weight of the concrete mixture. This consistency was maintained to guarantee a fair comparison among the different mix designs. The two crucial strengths of compressive and flexural force are investigated and their ratios are also evaluated. In the design mix constantly M sand was taken. The three mix designs were traditional M-sand concrete, M-sand concrete with jute fiber and M-sand concrete with coconut fiber. In this study, native river sand is fully substituted with M sand and no chemical admixture is added. The mechanical properties of compressive and flexural strength tests were checked with mean and standard deviation. The coconut-fiber M-sand concrete has reached its utmost compressive and flexural strengths of 19.3% and 24.8% respectively. With coconut fiber M-sand concrete, the ratio of compressive to flexural strengths is at its highest, 0.31.

Resumo em Inglês:

ABSTRACT The usage of by-products stems from industry offers a promising avenue for promoting clean production, waste minimization, and reducing greenhouse gas emissions, thus fostering environmental sustainability. This study delves into the performance evaluation of palm oil fuel ash (POFA) in concrete, aiming to assess its impact on strength, flowability, durability, and microstructure. The findings indicate that incorporating POFA into concrete mixes, up to a 12% dosage enhances compressive, flexural, and splitting tensile strengths. However, higher POFA content leads to decreased workability. Notably, the study divulges a significant control over chloride ingress with the addition of POFA, suggesting its potential to mitigate degradation in aggressive environments. Microstructural analysis of the specimens further highlights the promising role of POFA in enhancing concrete performance under adverse conditions, affirming its viability as a sustainable alternative in construction materials.

Resumo em Inglês:

ABSTRACT In this work, the evolution and formation of the amorphous phase during the preparation of amorphous Co67Si23B10 (at.%) powder by mechanical alloying (MA) under an argon atmosphere were studied. The grinding time of 15 h had a profound effect on the phase transformation, microstructure, morphology development, and thermal and magnetic behavior of the powders. These effects were studied by X-ray diffraction (XRD), EDX scanning electron microscopy (SEM), thermal analysis (TGA/DTA), N2 texture analysis (BET/BJH) and, magnetic measurements (VSM). The results show that the evolution of the amorphous phase in the early stage of milling consists of nanocrystalline α-Co2B and β-Co2Si phases, which are diluted and coexist with the amorphous phase. After 15 hours of ball milling, the amorphous phase became the main phase with a proportion of 98.1%, which is relatively high compared to the 1.9% of the nanocrystalline phases α-Co2B and β-Co2Si. The results obtained indicate that amorphization develops with higher thermal stability than a small fraction of the nanocrystalline phase diluted in the amorphous phase. This behavior suggests the presence of the amorphous phase coexisting with the nanocrystalline phase in a small fraction with overlapping crystallization and recrystallization at a temperature of around 924.42°C.

Resumo em Inglês:

This study explores the use of commonly utilized materials (sulphoaluminate cement, fly ash, expanding agent) in the creation of three inorganic coatings (C-coating, F-coating, E-coating) to improve the interlayer bonding properties of 3D printed mortar. The mechanical properties of mortar with/without coating were characterized by compressive test and flexural test. The bonding properties of the coatings were assessed through splitting tests and micron indentation tests. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to analyze the characteristics of hydration products and pore structure. The findings demonstrate that both F-coating and E-coating significantly enhance the mechanical properties of 3D printed mortar. Specifically, F-coating led to a 42% increase in flexural strength and a 71% increase in bond strength. The XRD and SEM analyses revealed that the fly ash contained in F-coating has a pozzolanic effect by reducing the content of Ca(OH)2 (CH), promoting the formation of calcium silicate hydrate (C-S-H) gel, and enhancing microscopic morphology. The expansion agent contained in the E-coating could significantly increase the content of AFt, and the needle-like AFt plays a good bonding performance between the interfaces. In this manuscript, two kinds of cheap and easy-to-obtain interlayer coatings for 3D printing mortar are found.

Resumo em Português:

RESUMO A madeira é um material amplamente utilizado em estruturas desde tempos antigos, porém, devido ser um material orgânico, suas propriedades possuem grande variação, o que pode impactar no desempenho estrutural. O reforço com compósitos de polímeros reforçados com fibras (FRP), especialmente pela técnica NSM, oferece melhorias significativas nas propriedades mecânicas das estruturas de madeira. Alguns estudos visam avaliar o efeito da utilização de diferentes fibras, bem como diferentes disposições das barras na seção transversal. Ainda assim, a contribuição estrutural obtida ao adotar diferentes tipos de fibras como reforço em vigas de madeira e a utilização de barras nas faces inferior e superior da seção transversal da viga ainda não foi amplamente avaliada. Este estudo teve como objetivo investigar o impacto da adição de barras na região comprimida e do tipo de fibra na rigidez e capacidade de carga de vigas de madeira. Para isso, foi realizado um estudo paramétrico por meio de simulação numérica em um software de análise por elementos finitos. Os resultados obtidos permitiram concluir que uma taxa de reforço de 1% permitiu aumentar a capacidade resistente da viga em até 14,25%, similar ao obtido em outros estudos com maiores taxas de reforço, porém com outras disposições das barras. As barras de CFRP proporcionaram os melhores resultados, seguidas das barras de GFRP e BFRP respectivamente.

Resumo em Inglês:

ABSTRACT Timber is a material that has been widely used in structures since ancient times, but because it is an organic material, its properties vary greatly, which can have an impact on structural performance. Strengthening with fiber-reinforced polymer (FRP) composites, especially using the NSM technique, offers significant improvements in the mechanical properties of timber structures. Some studies have evaluated the effect of using different fibers, as well as different arrangements of the bars in the cross-section. Even so, the structural contribution obtained by adopting different types of fibers as strengthening in timber beams and using bars in the lower and upper faces of the beam cross-section has not yet been widely evaluated. The aim of this study was to investigate the impact of adding bars in the compressed region and the type of fiber on the stiffness and load capacity of timber beams. To this end, a parametric study was carried out using numerical simulation in finite element analysis software. The results showed that a strengthening rate of 1% increased the beam's load-bearing capacity by up to 14.25%, similar to that obtained in other studies with higher strengthening rates, but with different bar arrangements. CFRP bars provided the best results, followed by GFRP and BFRP bars respectively.

Resumo em Português:

RESUMO A fosfatização é um tratamento de superfícies metálicas muito utilizado no meio industrial pois proporciona maior aderência do filme de tinta ao substrato metálico e maior eficiência na inibição da corrosão. Os agentes condicionantes no processo de fosfatização contribuem para a redução do tempo de obtenção da camada de fosfato e favorecem o refinamento dos cristais formados. Comercialmente, o agente condicionante mais utilizado é a base de sais de titânio, no entanto, é possível que outros compostos, possam ser uma alternativa na otimização do processo industrial. Portanto, com o intuito de reduzir o tempo e a temperatura do processo de fosfatização, esse trabalho tem por objetivo verificar o desempenho do uso do agente condicionante a base de fosfato de zinco na obtenção da camada fosfatizada, quanto à resistência à corrosão, em comparação ao condicionador à base de titânio. Para tanto, amostras de aço carbono SAE 1010 foram desengraxadas e jateadas, imersas por 1 minuto na solução condicionante (titânio ou fosfato de zinco) e fosfatizadas com solução comercial de fosfato de zinco tricatiônico em diferentes temperaturas (40 e 50°C) e tempos de imersão (2, 3 e 4 minutos). As massas depositadas dos revestimentos de fosfato foram medidas e os revestimentos caracterizados por microscopia eletrônica de varredura (MEV), por meio de ensaios eletroquímicos de potencial de circuito aberto e polarização potenciodinâmica. Os resultados mostraram que a maior cobertura do substrato, com a formação de camadas mais densas melhora o desempenho anticorrosivo das amostras fosfatizadas com ambos condicionadores. Para o condicionador a base de titânio, as condições ótimas de fosfatização foram de 3 min a 50°C, enquanto para o condicionador de fosfato de zinco, foram de 2 min a 40°C. Portanto, indica-se para uso comercial a imersão em condicionador a base de fosfato de zinco, seguido de fosfatização por 2 min a 40°C.

Resumo em Inglês:

ABSTRACT Phosphating is a metallic surface treatment widely used in the industrial environment as it provides greater adhesion of the paint film to the metallic substrate and greater efficiency in inhibiting corrosion. The conditioning agents in the phosphating process contribute to reducing the time to obtain the phosphate layer and favor the refinement of the formed crystals. Commercially, the most used conditioning agent is based on titanium salts, however, it is possible that other compounds may be an alternative in optimizing the industrial process. Therefore, with the aim of reducing the time and temperature of the phosphating process, this work aims to verify the performance of using the conditioning agent based on zinc phosphate in obtaining the phosphatized layer, in terms of corrosion resistance, in comparison with to the titanium-based conditioner. For this purpose, SAE 1010 carbon steel samples were degreased and sandblasted, immersed for 1 minute in the conditioning solution (titanium or zinc phosphate) and phosphated with a commercial solution of tricationic zinc phosphate at different temperatures (40 and 50°C) and immersion times (2, 3 and 4 minutes). The deposited masses of the phosphate coatings were measured and the coatings characterized by scanning electron microscopy (SEM), through electrochemical tests of open circuit potential and potentiodynamic polarization. The results showed that the greater coverage of the substrate, with the formation of denser layers, improves the anticorrosive performance of samples phosphated with both conditioners. For the titanium-based conditioner, the optimal phosphating conditions were 3 min at 50°C, while for the zinc phosphate conditioner, they were 2 min at 40°C. Therefore, for commercial use, immersion in a zinc phosphate-based conditioner is indicated, followed by phosphating for 2 min at 40°C.

Resumo em Inglês:

ABSTRACT The study investigates the possibility of using solid waste as an ecologically beneficial method in the manufacturing of concrete. It looks at the effects of replacing cement with glass powder at percentages ranging from 0% to 30% and a continuous 10% micro-silica replacement. The research evaluates a number of characteristics, including as resistance to freeze/thaw cycles, surface water absorption, capillary water absorption, tensile strength, bending strength, and workability. The results show that adding glass powder to concrete improves its fresh characteristics and workability. However, using glass powder in place of 30% cement results in a little loss of mechanical characteristics. In contrast to other mix designs, the concrete mixes containing 22.5% glass powder exhibit the highest increases in tensile, flexural, and compressive strengths (16.99, 23.53, and 17.65%, respectively). Concretes including 30% glass powder outperform the control design even if the strength criteria are somewhat reduced.

Resumo em Inglês:

Abstract Composite CST with lightweight concrete as infill for three light concrete grades such as M20 to M40 with different loading conditions. The optimal solutions as standard concrete and natural aggregate, waste material from the quarry are collected and added for replacement of natural sand in construction. While causing the experiment, cost and time will be extended, and the structural lightweight concrete mixes attain these can be designed. In present study, lightweight concrete materials are used to prepare the concrete mix with different proportion by replacement of quarry dust instead of sand and analysed the mechanical and other properties using machine learning techniques. The materials used in the present study were cured at the interval of 7 and 28 days, to train the Neural Network (NN) with Hidden layer neuron (HLN) maximization process Modified Krill Herd Optimization (MKHO) model used and these are initially considered. All the ideal results in the planned system demonstrate how the achieved mistake values among the different trail mixes and the predicted value of various mix proportion are obtained as zero and equivalent to zero. Based on the present study results, optimal model exactness is around 98.78% with other machine learning models.