Mestrado em Engenharia Civil
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- ItemOtimização topológica de pisos em treliças mistas tubulares com lajes mistas : análise de custos e emissões de CO2(Universidade Federal do Espírito Santo, 2025-08-22) Silva, Chayana Morgner Gomes da; Calenzani, Adenilcia Fernanda Grobério ; https://orcid.org/0000-0002-0936-9950; http://lattes.cnpq.br/9959808218883879; Alves, Élcio Cassimiro ; https://orcid.org/0000-0001-6971-2645; http://lattes.cnpq.br/6509450210637509; https://orcid.org/0009-0001-5367-2957; http://lattes.cnpq.br/5148699094876758; Melo, Antônio Macário Cartaxo de ; https://orcid.org/0000-0003-0398-4124; http://lattes.cnpq.br/2798137522735300; Silva, André Tenchini da ; https://orcid.org/0000-0003-0925-1159; http://lattes.cnpq.br/7036280752466413The objective of this study is to optimize the costs and CO₂ emissions of composite floor systems supported by composite tubular trusses, with and without concrete filling in the upper chord, considering the effect of vibrations induced by human walking. For the optimization problem, constraints related to the ultimate and service limit states of the composite slabs after concrete curing, and of the composite trusses before and after curing, were implemented. The optimization problem considered twenty-one design variables, including: circular profiles of the lower, upper, and diagonal members of the internal, edge, and main trusses; concrete strength (𝑓𝑐𝑘) of the slab; thickness of the steel deck; thickness of the concrete slab; number of truss panels; truss height; concrete strength (𝑓𝑐𝑘) of the filling in the upper chord of the internal, edge, and main trusses; span between internal trusses; and additional reinforcement. The Particle Swarm Optimization (PSO) algorithm was used to search for the optimal solution. To validate the implemented computational code, comparative analyses were first carried out with problems from the literature to verify the effectiveness of the proposed formulation. Subsequently, a parametric analysis was performed by varying the live loads and spans to identify the most influential factors in the solution. Finally, the effects of considering the comfort limit state of users related to human walking, and the influence of concrete filling in the upper chords of the trusses, were analyzed in the search for the optimal floor solution. It was concluded that concrete filling in the upper chords of the trusses contributes to reducing the number of truss panels and the cross-sectional area of the profiles, resulting in lower emissions and costs compared to full web beams. The analysis of floor vibration effects directly influenced the geometry of the internal and main truss sections, due to the need to provide greater structural stiffness
- ItemOtimização multiobjetivo no projeto de lajes mistas de aço e concreto(Universidade Federal do Espírito Santo, 2025-08-14) Silva, Isabela Oliveira Maia da; Alves, Élcio Cassimiro; https://orcid.org/0000-0001-6971-2645; http://lattes.cnpq.br/6509450210637509; Calenzani, Adenilcia Fernanda Grobério ; https://orcid.org/0000-0002-0936-9950; http://lattes.cnpq.br/9959808218883879; https://orcid.org/0009-0003-0976-9510; http://lattes.cnpq.br/2866501864088026; Dias, João Victor Fragoso; https://orcid.org/0000-0003-1455-1519; http://lattes.cnpq.br/0090215976146284; Kripka, Moacir; https://orcid.org/0000-0002-1997-3414; http://lattes.cnpq.br/7554233520986997The composite steel and concrete slabs have been used as a more economical and sustainable structural alternative since they offer advantages that outweigh other structural systems. Dispensing with formwork and shoring, high construction speed, and reduction in concrete and tensile reinforcement consumption are advantageous features of composite slabs. In this context, the aim of this study is to present the formulation of a multi-objective problem for composite slabs, considering the minimization of CO₂ emissions and final costs, as well as the maximization of load capacity. The design constraints followed the prescriptions of Brazilian standards for both construction and service phases. For the initial phase (before concrete curing), the design consists of verifying the steel formwork supporting the applied loads alone, using the Effective Width Method (EWM) as prescribed by ABNT 14762:2010. For the service phase (after concrete curing), the design was based on ABNT NBR 8800:2024, considering the composite steel system resisting the slab loads. To solve the optimization problem, the MOPSO (Multi-Objective Particle Swarm Optimization) algorithm was used to generate and analyze results through Pareto Fronts. For program validation, a verification of the cataloged slabs was conducted, maintaining their geometric and material properties, and investigating the possibility of loads exceeding those specified in the manufacturer's tables. Solutions were presented that are capable of supporting up to 1.54 times the load indicated by the manufacturer. The formulation was validated using problems from the literature, and an analysis of manufacturer-proposed solutions for different spans was conducted. Additionally, an equation was proposed to relate CO₂ emissions to cost. The results indicate that MOPSO was efficient in finding optimal solutions, yielding results very close to those in the literature using single objective formulations. With the proposed formulation, solutions were achieved with up to 2.4 times the design load proposed in catalogs, and up to 35% lower CO₂ emissions and 30% lower cost due to additional reinforcement. Moreover, solutions were obtained for spans exceeding the maximum limits provided by manufacturers by using concrete with compressive strength greater than 30 MPa. According to the results, the problem constraints are: verification of the steel formwork for bending moments before concrete curing, and verification of the composite section for longitudinal shear after curing
- ItemAvaliação do desempenho de concretos autocicatrizantes produzidos com materiais cimentícios suplementares submetidos à migração de íons cloreto(Universidade Federal do Espírito Santo, 2025-08-14) Rangel, Heitor Antonio Tschaen; Vieira, Geilma Lima; https://orcid.org/0000-0001-6148-3307; http://lattes.cnpq.br/5783172236615493; https://orcid.org/0009-0006-1523-4565; http://lattes.cnpq.br/9038050514244052; Schankoski, Rudiele Aparecida; https://orcid.org/0000-0003-1306-3986; http://lattes.cnpq.br/3391191554375710; Pacheco, Fernanda; https://orcid.org/0000-0003-3455-491X; http://lattes.cnpq.br/1290352347466444The presence of cracks, one of the main pathological manifestations of concrete, promotes the appearance of other pathological manifestations. The self-healing of reinforced concrete, which enables the closure of cracks, is seen as a means to extend the service life of structures, generating economic benefits compared to the costs of rehabilitation. Thus, this study aimed to analyze the self-healing phenomenon in different types of concrete with regard to chloride ion migration, carried out through the test governed by ASTM C1202 (2022). In an attempt to identify the compounds formed during the self-healing process, an X-Ray Diffraction (XRD) test was performed using samples taken after the migration test. Additionally, the electrical resistivity test, governed by ASTM C1876 (2024), was conducted, along with the proposal of a visual tool for internal crack analysis, named Colorimetric Analysis Test for Internal Cracking and Self-Healing of Concrete (EACFAIC). For the evaluation, in addition to intact specimens, two ranges of induced cracking were produced in the studied concretes, which were as follows: 1 – Reference concrete with CP V ARI cement; 2 – Concrete with 10% silica fume replacement; 3 – Concrete with 50% fly ash replacement; 4 – Concrete with 75% blast furnace slag replacement; 5 and 6 – Concrete with crystalline additive in two dosages (1% and 5%). The study observed some degree of self-healing in all types of concrete analyzed. However, the highest performances—both in self-healing capacity and in resistance to chloride ion migration (ASTM C1202 test), were achieved with the mineral replacements. These substitutions significantly reduced the passing charge compared to the reference concrete, by 295.91% (Range 1) and 195.49% (Range 2) for blast furnace slag, 116.95% (Range 1) and 117.45% (Range 2) for silica fume, and 130.76% (Range 1) and 64.35% (Range 2) for fly ash. In the volumetric electrical resistivity test governed by ASTM C1876, the concretes with mineral additions confirmed their superiority over the cement-rich mixtures. In the EACFAIC analysis, internal self-healing was implicitly verified in all concretes, corroborating the other test results. The X-Ray Diffraction test identified two main compounds: silicon oxide, originating from the cement, and calcium carbonate, which confirms the hypothesis of self-healing in all concretes
- ItemAvaliação do desempenho de cimentos Portland com incorporação de escória de ferroníquel moída como material cimentício suplementar para estabilização de solos(Universidade Federal do Espírito Santo, 2025-09-19) Dutra, Felipe Oliveira; Pires, Patrício José Moreira; https://orcid.org/0000-0001-5445-1753; http://lattes.cnpq.br/0913529658589507; Pilar, Ronaldo; https://orcid.org/0000-0002-1906-2071; http://lattes.cnpq.br/6669573444640365; https://orcid.org/0009-0004-7605-7836; http://lattes.cnpq.br/3108409993957100 ; Rebelo, Karla Maria Wingler; https://orcid.org/0000-0001-6972-2528; http://lattes.cnpq.br/6432874252149858 ; Gomes, Guilherme José Cunha; https://orcid.org/0000-0001-9510-4600; http://lattes.cnpq.br/1437609255681568With the growing demand for sustainable pavement engineering solutions, ferronickel slag (FNS) has emerged as a promising substitute for conventional Portland cement clinker. Although FNS exhibits pozzolanic potential, its use in powder form for natural soil stabilization remains underexplored. In this study, laboratory-formulated cements (CFN cements) were produced by partially replacing clinker with milled and sieved FNS powder in varying proportions (e.g., CFN30 = 30% FNS replacement relative to clinker). These binders were evaluated through unconfined compressive strength (UCS), resilient modulus (RM), physicochemical dosage (PC), and Atterberg limit (AL) tests. Two soil types were investigated: red soil (RS; A-6 plastic clay) and purple soil (PS; A-4 silty soil), both stabilized with CFN formulations at a fixed dosage of 7% by dry soil mass. The results revealed a clear inverse linear relationship between clinker replacement level and mechanical performance, as reflected in UCS and RM values. Despite this trend, Tukey’s test (95% confidence) showed that CFN10 and CFN30 were statistically equivalent to Type I cement (ASTM C150), while CFN50 and CFN70 matched the performance of Type IS cement (ASTM C595), except for CFN70 in RS mixtures at 63 days. For RM, all binders performed similarly in RS mixtures, whereas in PS compositions, statistical differences emerged only at 63 days, with CFN30 and CFN50 equivalent to Type I cement and CFN70 to Type IS cement. RS mixtures consistently exhibited superior strength and stiffness compared to PS mixtures, highlighting the influence of soil mineralogy and granulometry. PC dosage confirmed the greater efficiency of RS, requiring only 8% cement for stabilization versus 10% for PS with the same CFN binder. AL results further indicated stronger pozzolanic reactivity in RS-based mixtures. These findings demonstrate the technical viability of FNS powder as a supplementary cementitious material (SCM) for soil stabilization and support its integration into sustainable pavement technologies. This approach aligns with global efforts to reduce clinker consumption, promote circular economy practices, and minimize environmental impacts.
- ItemAvaliação do ciclo de vida da produção de cimento portland com escória granulada de alto-forno(Universidade Federal do Espírito Santo, 2025-09-29) Vieira, Thalya Fortuna; Kulay, Luiz Alexandre; https://orcid.org/0000-0003-1107-1800; http://lattes.cnpq.br/2620449722890209 ; Schankoski, Rudiele Aparecida; https://orcid.org/0000-0003-1306-3986; http://lattes.cnpq.br/3391191554375710; https://orcid.org/0009-0000-2196-4894; http://lattes.cnpq.br/9299328408306728 ; Vieira, Geilma Lima; https://orcid.org/0000-0001-6148-3307; http://lattes.cnpq.br/5783172236615493; Campos, Alex Milton Albergaria; https://orcid.org/0000-0002-2338-4751; http://lattes.cnpq.br/0483146736276629 ; Rodrigues, Thiago Oliveira; https://orcid.org/0000-0002-0207-7752; http://lattes.cnpq.br/1312518668807552The materials used in civil construction, especially Portland cement, have a significant environmental impact. To reduce these negative environmental consequences, replacing natural raw materials with steel byproducts is a technically feasible practice in several segments of this industry. An effective tool for calculating and quantifying these environmental impacts is Life Cycle Assessment (LCA). This master's thesis aims to conduct a comparative study of cements that incorporate granulated blast furnace slag (CP III), analyzing different allocation methods: by mass, by energy, by economic allocation, and even the non-application of the allocation procedure. For comparison, Portland cement without the addition of type V slag (CP V) was used as a reference. The LCA technique was applied to a cradle-to-gate scope of the cement plant, with a reference flow of 1 ton of cement. To construct the inventory, we used primary data (obtained directly from cement and steel mills) and secondary data (from the literature and the Ecoinvent database). Data entry, impact simulations, and uncertainty analysis were performed using SimaPro® software. Sensitivity analyses were conducted with different slag contents incorporated into the cement. Four energy scenarios were also evaluated: wind, hydroelectric, photovoltaic, and the typical Brazilian scenario. At the end of the simulations, it was concluded that CP III cement has better environmental performance than CP V for all impact categories analyzed. In the global warming category, according to the IPCC 2021 method, the impacts of CP III are 70% lower than CP V. Replacing the thermoelectric energy grid with wind energy minimizes CO2 emissions by up to 25%.