http://repositorio.ufc.br/handle/riufc/480 Tue, 09 Jun 2026 23:23:00 GMT 2026-06-09T23:23:00Z http://repositorio.ufc.br/handle/riufc/86429 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 Tue, 22 Apr 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86429 2025-04-22T00:00:00Z http://repositorio.ufc.br/handle/riufc/86092 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 Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86092 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/84539 Título: Análise do custo do ciclo de vida das estratégias para manutenção da resistência à derrapagem em pista de pouso e decolagem Autor(es): Carneiro, Rayssa de Sousa Abstract: Maintenance and rehabilitation (M&R) of airport pavements are essential to ensure skid resistance, which directly impacts the safety of landing and takeoff operations. To comply with the guidelines set by the National Civil Aviation Agency (ANAC), airport operators must carry out M&R in a way that optimizes scarce financial resources while maintaining optimal operational safety conditions. In this context, Life-Cycle Cost Analysis (LCCA) provides a rational framework to support M&R decisions, promoting the efficient use of resources. This study aims to evaluate M&R strategies focused on ensuring skid resistance on Brazilian runways, based on LCCA. Three M&R scenarios were compared for three runways with different surface treatments (asphalt concrete, grooved asphalt concrete, and porous friction course), focusing on maintaining skid resistance, as measured by the friction coefficient. The study used predictive models based on historical data to estimate the behavior of the friction coefficient and determine the appropriate timing for interventions on each runway. The economic evaluation using LCCA was carried out through Net Present Value (NPV) analysis, both deterministically and probabilistically, considering direct costs, and was complemented by a cost-effectiveness analysis. A reduction in the friction coefficient was observed in all three runways after the last rehabilitation, indicating surface texture wear and suggesting that isolated rubber removal may not be sufficient, thereby highlighting the need for M&R interventions.The LCCA results showed that preventive maintenance is more advantageous regardless of surface type, as it reduces both costs and their variability, in addition to being more effective in preserving skid resistance. Conversely, performing rehabilitations only when the friction coefficient falls below the minimum threshold results in higher costs and compromises operational safety. The runway with grooved asphalt concrete presented the highest predicted friction coefficient values; however, it incurred higher life-cycle costs. LCCA proved to be effective in the economic evaluation of M&R strategies aimed at ensuring skid resistance, enabling the efficient allocation of financial resources and contributing to pavement durability and operational safety. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/84539 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/84517 Título: Análise da influência dos planos diretores de Fortaleza na localização de armazéns logísticos Autor(es): Brito, Bruno Reges Almeida de Abstract: This dissertation investigates the interaction between urban planning and the distribution of logistics warehouses in the city of Fortaleza, analyzing how urban planning guidelines influence the location of these facilities and contribute to the process of logistics expansion. Rapid population growth in urban areas demands an increasing movement of goods, essential for the daily functioning of cities, making the strategic location of logistics warehouses crucial for the efficiency of urban freight transport (UTC). The premise is that the relocation of warehouses in recent decades is influenced by a lack of coordination between urban planning and logistics systems, as well as guidelines that fail to ensure efficient accessibility to urban freight. Therefore, the research seeks to answer the central question: "How are logistics warehouse locations influenced by urban planning?" by analyzing the guidelines in Fortaleza's master plans and their relationship with warehouse locations, and consequently, accessibility in the context of freight. To this end, a systematic literature review is conducted to consolidate planning guidelines that may affect the distribution of these facilities. Next, we evaluate the application of these guidelines in master plans over time and their impact on warehouse locations. Finally, we seek to characterize changes in urban freight accessibility during the analyzed period, observing variations in observed locations and those proposed in master plans. This research provides valuable insights for integrating urban planning and logistics needs, aiming to optimize warehouse locations and develop more effective land use policies. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/84517 2025-01-01T00:00:00Z