http://repositorio.ufc.br/handle/riufc/459 2026-06-15T13:52:30Z 2026-06-15T13:52:30Z Sombra Junior, Adriano Jorge http://repositorio.ufc.br/handle/riufc/86429 2026-05-22T17:43:08Z 2025-04-22T00:00:00Z

Título: Avaliação do uso de geopolímeros para a melhoria de propriedades mecânicas de subcamadas de pavimentos Autor(es): Sombra Junior, Adriano Jorge Abstract: The high demand for natural materials in road construction, combined with the fact that soils from borrow pits near construction sites do not always possess suitable mechanical properties, makes it necessary to stabilize these materials for use in pavement sublayers. Portland cement and lime are the binders commonly used in the chemical stabilization of soils. However, in addition to their high cost, their manufacturing processes cause environmental damage due to the intensive consumption of natural resources and the high emission of greenhouse gases. In this context, geopolymeric materials emerge as a sustainable alternative for chemical stabilization. These materials incorporate industrial waste and by-products in their composition and exhibit cementitious characteristics capable of improving the mechanical properties of soils. Within this framework, the main objective of this study is to investigate, through chemical, physical, and mechanical tests, the feasibility of synthesizing and applying geopolymers in pavement sublayers to improve soil mechanical properties. The main challenge of the research was the synthesis of geopolymers using fly ash (F), BSSF-type steel aggregate (Baosteel Slag Short Flow), and petroleum coke powder (C). To assess the improvement in the soil's mechanical properties, the unconfined compressive strength (UCS) test was used as a preliminary analysis of the technique's viability. The precursors were selected, treated to remove soluble salts, and then binary material combinations were defined, which were subjected to alkaline activation, microstructural characterization, and application to a clayey soil. The stabilization process involved the molding of 600 specimens using miniature equipment, of which 528 were used for UCS analysis with both dry and wet curing at 7, 14, 21, and 28 days, and 72 for investigating shrinkage and expansion effects. The results showed that soils stabilized with geopolymers at different precursor dosages exhibited strength gains. The UCS gain was gradual and showed satisfactory values under air-curing conditions, with the best results obtained using petroleum coke powder. The study developed here highlights the potential of geopolymers produced with alternative materials to improve soil properties for application in pavement sublayers, as well as reduce the environmental impacts associated with road construction. Tipo: Dissertação

2025-04-22T00:00:00Z Silva, Webert Brasil Cirilo da http://repositorio.ufc.br/handle/riufc/86397 2026-05-20T20:11:54Z 2026-01-01T00:00:00Z

Título: Analysis of the mechanical and environmental performance of concrete interlocking block pavement with by-products from the construction industry and waste from coconuts Autor(es): Silva, Webert Brasil Cirilo da Abstract: Urban road pavements made of concrete paving blocks (PB) and granular layers, such as base and sub-base, using industrial waste, are an improving sustainability goal for low to intermediate traffic areas due to the lack of helpful disposal of by-product generation. Then, this Dissertation aims to evaluate, by an innovative approach, the mechanical and environmental performance of concrete interlocking block pavement (CIBP) with by-products from the construction industry (construction and demolition waste – CDW) and waste from coconuts (coconut fibers – CF) for urban roads. Furthermore, a Life Cycle Cost Analysis (LCCA) was proposed for CIBP’s maintenance and reliability strategies. As this Dissertation was divided into four articles, a review paper was done first to compare CIBP skills with asphalt pavement (AP) for light-traffic urban roads. Regarding the second article, eighteen mixes for rectangular PB were used in Portugal with three water/cement ratios of 0.63, 0.73 and 0.83, CDW replacement rates of 50% and 75% by aggregate weight, and a CF adding percentage of 0.1% by concrete weight. Concerning the results, the CDW replacement of 75% by aggregate weight, CF adding of 0.1% and water/cement ratio of 0.73 were factors for providing PB for low-trafficked road pavements. About the third and fourth articles, a 175 m2–CIBP was built in Brazil with five experimental sections (S1, S2, S3, S4 and S5), four mixes for unistein PB with a CDW dust replacement rate of 50% by stone dust weight, and a CF dust adding percentage of 0.05% by concrete weight. Furthermore, eight granular mixtures made from non-plastic materials for base and sub-base layers were utilized with a CDW replacement rate of 100% and a CF adding percentage of 0.1% by mix weight. Regarding the third article, the air and surface temperatures from CIBP’s sections S1 to S5 were lower than the asphalt concrete from section S0. Furthermore, the CIBP construction stages showed average concentrations of particulate matter and carbon dioxide below the specifications. Concerning the fourth article, the CDW replacement of 50% by stone dust and CF adding of 0.05% were factors for concrete mixtures presented PB approved in specifications for water absorption and abrasion resistance tests. Also, the compressive and tensile strains from experimental CIBP in Brazil were lower than experimental AP in Portugal. About the LCCA on CIBP’s sections, S4 with CF and CDW materials showed costs lower than S2, S3 and S5 in 2045. These findings highlighted construction and coconut by-products for PB and sublayers as an alternative for the CIBP’s mechanical, environmental and economic feasibility. Tipo: Tese

2026-01-01T00:00:00Z Matos, André Luis Barcelos http://repositorio.ufc.br/handle/riufc/86092 2026-04-29T19:54:33Z 2026-01-01T00:00:00Z

Título: Fatores intervenientes no comportamento de motociclistas quanto à velocidade: um estudo sob a ótica da teoria do comportamento planejado estendida Autor(es): Matos, André Luis Barcelos Abstract: The intensive use of motorcycles has increased traffic fatality rates, especially in countries such as Brazil. Among the risk factors, speed choice stands out. Understanding the elements that influence this decision is essential for planning road safety actions. This study aims to identify the factors influencing motorcyclists' intention to comply with speed limits, using the Extended Theory of Planned Behavior (TPB). A risk perception construct was included to reflect motorcyclists’ intuitive judgments about the consequences of speeding. Furthermore, the influence of gender and motorcycle use in the TPB framework was also investigated. To this end, the Motorcyclist Speed Compliance Questionnaire (MSCQ) was developed, based on the study of salient local beliefs and applied to a sample of 358 motorcyclists in Fortaleza City, Brazil. The consolidated psychometric instrument was used to test a set of hypotheses using Structural Equation Models. The results showed the strong effect of perceived behavioral control and attitude on the intention to comply with speed, as well as the central role of risk perception on attitude and perceived behavioral control. It also appears that, at least for the Fortaleza city scenario, peer influence plays an indirect role in motorcyclists speed compliance. Based on the hypothesis testing and the final TPB/SEM analysis, several safety interventions were recommended. Tipo: Dissertação

2026-01-01T00:00:00Z Maia, Camila Lima http://repositorio.ufc.br/handle/riufc/85740 2026-04-10T11:46:12Z 2026-02-25T00:00:00Z

Título: Método integrado de análise econômica e ambiental do ciclo de vida de pavimentos aeroportuários brasileiros para apoio à tomada de decisão em manutenção e reabilitação Autor(es): Maia, Camila Lima Abstract: The growing demand for safety and operational efficiency in airports reinforces the need for more sustainable and economically efficient solutions for airport pavement management. In this context, Life-Cycle Cost Analysis (LCCA) emerges as a tool to support rational decision-making over time, allowing the evaluation of costs associated with different maintenance and rehabilitation (M&R) strategies. However, many LCCA studies focus primarily on functional parameters, such as the Pavement Condition Index (PCI), without incorporating indicators related to skid resistance, which are essential for the safety of landing and takeoff operations. In addition, LCCA does not incorporate the environmental impacts associated with M&R interventions. Given this context, this study aimed to develop an integrated economic and environmental analysis method for the design period of Brazilian airport pavements, combining Life-Cycle Cost Analysis (LCCA) and Life-Cycle Assessment (LCA), while considering functional, structural, and skid resistance parameters. Data from a Brazilian runway, provided by the National Civil Aviation Agency, covering the period from 2014 to 2023, were used, including PCI, friction coefficient, macrotexture, and the Cumulative Damage Factor (CDF), obtained using the FAARFIELD 2.1.1 software. Prediction models were developed in Python, using Gated Recurrent Unit (GRU) recurrent neural networks for the friction coefficient and macrotexture, and a deterioration rate model for PCI. The combination of performance predictions with the structural analysis performed in FAARFIELD 2.1.1 allowed the identification of M&R needs and the simulation of different intervention scenarios for time horizons of 20, 30, and 40 years through decision trees. The proposed method integrated both financial and environmental costs. The environmental impacts were estimated through an LCA conducted in the SimaPro Demo software, using the ReCiPe Midpoint (H) method, considering a functional unit of 1 m2 of runway, followed by the monetization of CO2 equivalent emissions. Additionally, a sensitivity analysis was carried out considering different discount rates. The friction coefficient and macrotexture models presented satisfactory performance, although the accuracy of the macrotexture model decreased for higher values. Preventive maintenance proved to be the most advantageous alternative in short-term horizons, reducing the Net Present Value (NPV) of M&R costs and postponing high-cost corrective interventions. However, in longer horizons, environmental impacts increased due to the recurrence of delayed corrective interventions, making the NPV of environmental costs more sensitive to the accumulation of emissions over time. Nevertheless, the NPV of total costs remained lower in the scenario prioritizing preventive maintenance, demonstrating its economic robustness. The sensitivity analysis of the discount rate showed that, over a 20-year horizon, the total NPV presented low variation, while over 30 years the difference between discount rates was moderate. Over a 40- year horizon, delayed costs—particularly environmental costs—made the total NPV more sensitive to variations in the discount rate. Overall, the proposed method demonstrates strong potential to support decision-making in defining M&R strategies. By integrating functional performance, skid resistance, structural behavior, and environmental impacts, this research contributes to more efficient and sustainable airport pavement management practices, aligned with the increasing demands for operational safety and economic rationality in Brazilian airports. Tipo: Tese

2026-02-25T00:00:00Z