http://repositorio.ufc.br/handle/riufc/459 2026-07-02T07:44:04Z 2026-07-02T07:44:04Z Ribas, Larissa Virginia da Silva http://repositorio.ufc.br/handle/riufc/86962 2026-06-30T20:28:14Z 2026-01-01T00:00:00Z

Título: Thermochromic functionalization of asphalt mixtures as an urban heat island mitigation strategy: assessing spray-coating performance and microclimatic impacts in a tropical environment Autor(es): Ribas, Larissa Virginia da Silva Abstract: Urban heat has become one of the most critical environmental challenges in contemporary cities. The extensive presence of impervious surfaces, particularly asphalt pavements, intensifies solar absorption and heat storage, significantly contributing to the formation and persistence of urban heat islands (UHIs). Because pavements occupy large portions of urban areas, they constitute a strategic surface for implementing sustainable cooling solutions. In this context, the thermochromic functionalization of asphalt pavements emerges as a promising cool pavement strategy, as it enhances the surface’s capacity to modulate temperature. Thermochromic materials reversibly change color according to temperature, modifying surface albedo and increasing solar reflectance under high thermal conditions. The main objective of this research is to evaluate how the thermochromic capacity of asphalt pavement surfaces, functionalized through a surface spraying technique, influences the formation and mitigation of UHI effects. This dissertation is organized into four main parts. First, a bibliometric analysis followed by a systematic literature review investigates the current scientific panorama of thermochromic asphalt pavements’ functionalization, identifying research trends and knowledge gaps. Second, experimental studies evaluate the effects of thermochromic spray coatings applied to recycled asphalt mixtures on surface texture and cracking resistance. Laboratory analyses include colorimetry, texture characterization, pull-off adhesion tests, accelerated aging, and semi-circular bending (SCB) tests under long-term aging conditions. Third, outdoor experiments assess optical-thermal balance, cooling performance, and durability under environmentalexposure. Finally, a case study simulates the microclimatic impacts of the thermochromic strategy, including pedestrian thermal comfort, in different urban morphologies of a tropical city using computational fluid dynamics (CFD)-based modeling. Results indicate that thermochromic coatings reduce surface temperatures by 5–9 °C during peak solar radiation. The functionalization shows good adhesion, minimal changes in surface texture, and improved cracking resistance in aged specimens with 6% thermochromic content. However, accelerated weathering reveals reductions in solar reflectance over time, highlighting durability challenges. At the urban scale, simulations demonstrate surface temperature reductions of up to 9.6 °C and air temperature reductions of 1.7 °C. Nevertheless, thermal comfort analysis using the universal thermal climate index (UTCI) reveals that lower thermophysical variables do not necessarily result in improved daytime comfort, due to increased mean radiant temperature and the influence of urban canyon geometry. The findings confirm the potential of thermochromic pavements for UHI mitigation, while emphasizing the need for context-sensitive and integrated urban climate strategies. Tipo: Tese

2026-01-01T00:00:00Z 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