Mestrado em Engenharia Civil
URI Permanente para esta coleção
Nível: Mestrado Acadêmico
Ano de início:
Conceito atual na CAPES:
Ato normativo:
Periodicidade de seleção:
Área(s) de concentração:
Url do curso:
Navegar
Submissões Recentes
- ItemDurabilidade de concretos com incorporação de escória de Ferroníquel como material cimentício suplementar : migração de íons cloreto, carbonatação e análise microestrutural(Universidade Federal do Espírito Santo, 2026-02-26) Quinquim, Thiago Almeida; Sakata, Rafael Dors; https://orcid.org/0000-0002-7022-3846; https://lattes.cnpq.br/3547547454752538; Pilar, Ronaldo; https://orcid.org/0000-0002-1906-2071; https://lattes.cnpq.br/6669573444640365; https://orcid.org/0009-0000-5606-241X; https://lattes.cnpq.br/9143527494194512; Vieira, Geilma Lima; https://orcid.org/0000-0001-6148-3307; https://lattes.cnpq.br/5783172236615493; Araújo, Geórgia Serafim; https://orcid.org/0000-0002-2029-6334; https://lattes.cnpq.br/4707150428037806; Medeiros, Marcelo Henrique Farias de; https://orcid.org/0000-0003-3112-9715; https://lattes.cnpq.br/2049752365695485Partial replacement of Portland cement with supplementary cementitious materials (SCMs) is a consistent strategy to enhance the sustainability of the construction sector by reducing the clinker factor and its environmental impacts, especially when these materials are regionally available. This study investigated the technical feasibility of incorporating ground ferronickel slag (FNS) as an SCM in concrete, evaluating mechanical performance, durability indicators, and microstructural evidence. The mixtures were produced with a constant water-to-binder ratio and different replacement levels (including a reference mixture and a composition with inert limestone filler). Performance was assessed through compressive strength, chloride transport tests (passed charge and migration coefficient), electrical resistivity, volume of permeable voids, and accelerated carbonation. The interpretation of the results was supported at the microstructural level by synchrotron X-ray diffraction with quantitative refinement and thermogravimetric analysis, enabling relationships between composition/mineralogy and hydration evolution to be established. FNS, characterized by a low Ca/Si ratio and a considerable siliceous amorphous fraction, exhibited predominantly late pozzolanic reactivity, consuming Ca(OH)2 and forming additional C–S–H, which promoted matrix densification. At later ages, a consistent reduction in ionic transport and volume of permeable voids were observed, accompanied by increased electrical resistivity, indicating greater resistance to chloride ingress. However, high replacement levels increased vulnerability to carbonation, mainly at early ages, attributed to clinker dilution and reduced alkaline reserve, although late age densification partially mitigated this effect. Overall, replacement levels around 30% provided the best balance between mechanical performance, durability gains, and carbonation resistance.
- ItemAnálise de pilares mistos retangulares preenchidos submetidos à flexo-compressão : proposição de equações e ferramenta computacional(Universidade Federal do Espírito Santo, 2025-12-09) Miranda, Glaubert Araujo; Ferreira, Walnório Graça ; https://orcid.org/0000-0002-2079-6048; https://lattes.cnpq.br/9453786966994911; Calenzani, Adenilcia Fernanda Grobério ; https://orcid.org/0000-0002-0936-9950; https://lattes.cnpq.br/9959808218883879; https://orcid.org/0000-0002-0810-7318; https://lattes.cnpq.br/3705408452006714; Oliveira, Romilde Almeida de ; https://orcid.org/0000-0002-6786-9080; https://lattes.cnpq.br/9272579827887449; Rossi, Alexandre ; https://orcid.org/0000-0001-9590-1554; https://lattes.cnpq.br/3946998323160911Contemporary construction increasingly demands structural designs employing slender columns, aiming to optimize architectural space and reduce material consumption while maintaining safety and structural efficiency. Among the available solutions, composite columns with concrete-filled rectangular sections stand out as an efficient and economical alternative, especially when combined with high-strength steel and concrete. The design of these columns is based on the provisions of ABNT NBR 8800:2024, which presents simplified models for the flexural–compression verification of compact, semicompact, and slender sections. However, the standard does not provide expressions for determining the neutral axis position in semicompact and slender sections, nor for calculating the moments corresponding to the onset of compressive plastification in semicompact sections or the initiation of yielding in the tension flange of slender sections, which limits its practical application. In this study, a computational tool was developed in MATLAB for verifying concrete-filled rectangular composite columns subjected to flexural–compression, based on the design models of ABNT NBR 8800:2024. As a central contribution of the research, mathematical formulations are proposed to determine the neutral axis position and the moments associated with the initial stages of plastification and yielding in semicompact and slender sections, respectively. The tool enables automated generation of M–N interaction curves, facilitating the analysis of the structural behavior of these columns and helping to address existing gaps in the standard. To assess the adherence of normative methods to actual behavior, 37 experimental tests of rectangular concrete-filled steel tube columns reported in the literature were processed using the developed tool and evaluated according to ABNT NBR 8800:2024 and AISC 360-22. The results showed that, for compact sections, Model II of ABNT NBR 8800:2024 provided the best estimates, with mean ratios of normalized-to-ultimate moments (!!"#$%/!&,) ranging from 0.80 to 0.87. For semicompact and slender sections, Model III of ABNT NBR 8800:2024 and Method IV of AISC 360-22 yielded the most consistent—though conservative—predictions, highlighting the increase in conservatism of these models as both the sectional slenderness and steel strength increase
- ItemAnálises de dados de curvas de calibrações do papel filtro (sucção) e aplicações de redes neurais artificiais na estimativa da umidade obtida pela técnica TDR em solos não saturados(Universidade Federal do Espírito Santo, 2026-02-06) Santos, Nelson de Carvalho; Hisatugu, Wilian Hiroshi; https://orcid.org/0000-0001-8333-0539; http://lattes.cnpq.br/6597878238749014; Bicalho, Kátia Vanessa; https://orcid.org/0000-0002-2157-7322; http://lattes.cnpq.br/9639299365620025; https://orcid.org/0000-0003-1510-6759; http://lattes.cnpq.br/6900473115467465; Silva, Maristela Gomes da; https://orcid.org/0000-0002-7104-1972; http://lattes.cnpq.br/4450263733589061; Ferreira, Silvio Romero de Melo; https://orcid.org/0000-0002-5760-1494; http://lattes.cnpq.br/8035357058902261Soil water content (θv) and suction are variables that influence the hydraulic and mechanical behavior of unsaturated soils (US). However, direct measurements of these quantities may be costly and operationally limited, motivating the use of indirect methods, such as Time Domain Reflectometry (TDR), for estimating θv, and the filter paper method (FPM), for estimating matric or total suction. In this context, this dissertation aimed to analyze and compare the performance of artificial neural networks (ANNs) and regression equations in the calibration of TDR for estimating soil water content, as well as to evaluate the performance of bilinear and exponential calibration curves of the FPM, based on experimental data available in the literature, in estimating matric suction in different US. For TDR, a database was compiled from the literature aiming at calibration through regression equations and ANNs, considering as input variables the apparent dielectric constant (Ka), dry bulk density (BD), organic matter content (OM), and clay content (% clay). For the FPM, bilinear and exponential calibrations reported in the literature were evaluated, considering initially air-dried filter paper and the wetting contact path. The results indicated, for TDR, superior performance of ANNs compared to regression equations, with higher coefficients of determination (R2) and lower errors, expressed by the root mean square error (RMSE) and mean absolute error (MAE), in addition to better generalization capacity when applied to external datasets. It was observed that the exclusive use of Ka is insufficient to adequately represent the variability of θv, and the best-performing architectures were those combining Ka with BD, OM, and clay content, with emphasis on ANN12-6, which presented the best overall performance and behavior close to the ideal 1:1 condition for different soil types. For the FPM, bilinear calibrations generally remained within normative tolerances; however, they showed greater variability and performance loss under high suction regimes, especially in soils with higher fine fractions. Among exponential calibrations, better overall performance was observed, with estimates predominantly within confidence intervals. Overall, it is concluded that the appropriate selection of calibration approaches and input variables is essential to reduce uncertainties in estimating θv and suction in unsaturated soils, highlighting the superior performance of ANN-based approaches and exponential FPM calibrations.
- ItemEstabilização de solos com escória de ferroníquel e cimento portland: propriedades físicas, mecânicas, químicas e mineralógicas em aplicações de pavimentação(Universidade Federal do Espírito Santo, 2025-09-25) Botelho, Catarina Vieira; Pilar, Ronaldo; https://orcid.org/0000-0002-1906-2071 ; http://lattes.cnpq.br/6669573444640365; Pires,Patrício José Moreira ; https://orcid.org/0000-0001-5445-1753; http://lattes.cnpq.br/0913529658589507; https://orcid.org/0009-0003-7363-8988; http://lattes.cnpq.br/5450612057103403; Almeida, Guilherme Bravo de Oliveira; https://orcid.org/0000-0002-7447-9646; http://lattes.cnpq.br/4641090392417950; Alledi, Carla Therezinha Dalvi Borjaille ; https://orcid.org/0000-0002-8429-731X ; http://lattes.cnpq.br/4542859765962073This dissertation evaluates the technical feasibility of using ferronickel slag (FeNi) as a stabilizing agent and gradation corrector in two soils: a sandy soil (SL) and a silty fine soil (SR), with the aim of application in pavement layers. Mixtures with 30% and 60% FeNi, with and without 3% cement (CPIII and CFN50), were studied. The experimental program encompassed physical characterization (particle size distribution, specific gravity, organic matter content, Atterberg limits), chemical characterization (pH and cation exchange capacity), mineralogical characterization (XRF and XRD), and mechanical testing (compaction, California Bearing Ratio and swelling, as well as resilient modulus), with curing periods of 7 and 63 days. Results showed that FeNi is distinctly granular and of high density, shifting the mixtures towards a framework-controlled behavior and reducing plasticity, especially at 60% replacement. The SUCS, AASHTO and MCT classifications confirmed the trend toward more sandy materials. In compaction, the maximum dry unit weight increased, while the optimum moisture content decreased or remained stable with FeNi incorporation. The CBR increased significantly in SL mixtures with 3% cement, qualifying them as base course material, whereas pure SL and SL with FeNi but without cement met the requirements for subbase. In SR, relevant improvements occurred with FeNi, with or without 3% cement, placing the mixtures in the subbase category. Swelling remained very low in FeNi mixtures, complying with DNIT specifications. The resilient modulus increased with confining stress; in SR, the gain was governed by FeNi while cement had a secondary role, whereas in SL, cement was decisive and FeNi additionally contributed to the granular response. According to DNIT specifications, only SR+60%FeNi, with or without 3% cement, simultaneously met all requirements for subbase; considering only CBR and swelling, several SL formulations satisfied the base course criteria. It is concluded that FeNi is technically feasible as a component for base and subbase layers, with best performance at 60% content and in combination with low cement dosages, contributing to the valorization of by-products and to circular economy practices in pavement engineering.
- ItemAnálise da autocicatrização de diferentes tipos de concretos com vistas à durabilidade, por meio do ensaio de migração acelerada de íons cloreto(Universidade Federal do Espírito Santo, 2025-09-30) Paigel, Gabriel Agrisi; Vieira, Geilma Lima; https://orcid.org/0000-0001-6148-3307; http://lattes.cnpq.br/5783172236615493; https://orcid.org/0009-0001-0380-6275; http://lattes.cnpq.br/1550296610058631; Araújo, Georgia Serafim; https://orcid.org/0000-0002-2029-6334; http://lattes.cnpq.br/4707150428037806; Zuchetti, Laís; https://orcid.org/0000-0001-9328-3350; http://lattes.cnpq.br/This study evaluates the phenomenon of self-healing in concrete with mineral additions and a crystalline admixture to understand its impact on durability, especially in aggressive conditions like those exposed to chloride ions. Mix designs with ground granulated blast-furnace slag, fly ash, a crystalline admixture, and a reference mix with high-early-strength Portland cement were analyzed in both uncracked and cracked samples, with crack widths less than 0.2 mm and between 0.3 and 0.4 mm. The methodology included chloride migration tests (NT BUILD 492), electrical resistivity measurements, stereoscopic microscopy, and, as a complement, X-ray diffraction (XRD) analyses to verify the ability of these materials to resist the penetration of deleterious agents and promote crack sealing. The results indicated that all materials showed some degree of visible self-healing. Concrete with blast-furnace slag stood out for its high resistance to chloride penetration, with a reduction of about 40% in penetration depth compared to the concrete with the crystalline admixture, in addition to showing higher electrical resistivity. In terms of self-healing, the concretes with fly ash and the crystalline admixture showed the best performance, while the slag demonstrated an intermediate behavior. The combined analysis of microscopy and XRD confirmed the formation of calcium carbonate (CaCO₃) as the main sealing product. The statistical analysis showed that the concrete's composition significantly influences its resistance to chloride penetration, while the crack width, within the studied ranges, did not have a relevant impact on the healing capacity. It is concluded that the use of mineral additions and specific admixtures is an effective strategy for producing more durable, resilient, and sustainable concrete.