http://repositorio.ufc.br/handle/riufc/81526 Sun, 12 Apr 2026 04:13:23 GMT 2026-04-12T04:13:23Z http://repositorio.ufc.br/handle/riufc/85434 Título: Avaliação das propriedades eletromecânicas de compósitos cimentícios à base de MWCNTs, CFs e EPS para aplicação em sensoriamento Autor(es): Araújo, Antônio José Cruz de Abstract: Concrete structures are widely used due to their durability, but they are subject to degradation, which compromises their integrity. In this context, self-sensing cementitious composites, obtained through the incorporation of electrically conductive additions such as carbon fibers (CFs) and carbon nanotubes (CNTs), emerge as an alternative for structural monitoring due to their piezoresistive properties. In light of this, the present study aimed to develop lightweight self-sensing cementitious composites based on multi-walled carbon nanotubes (MWCNTs), CFs, and expanded polystyrene (EPS) for sensing applications. To evaluate the behavior of the produced mortars, tests were carried out for workability, water absorption, void index, and density, ultrasonic pulse velocity, compressive strength, and electromechanical performance. Initially, a pilot study was conducted to investigate the isolated effects of different concentrations of CFs (0.10%, 0.20%, 0.50%, and 1.00%) and EPS (20% and 30%), in addition to the incorporation of 0.2% MWCNTs. Mortars produced with MWCNTs showed good electromechanical results but exhibited an 8.95% reduction in compressive strength, indicating agglomeration. Among the mortars with CFs, the 0.1% content showed the best results, with a compressive strength of 55.58 MPa and a favorable electromechanical response. For EPS, the 30% content caused a significant reduction in compressive strength of 51.30%, while the other parameters remained close to those observed for the 20% content. Based on the mixtures that presented the best compressive strength and piezoresistive behavior in the pilot study, the optimal contents for multicomponent composites were defined (20% EPS, 0.1% CFs, and 0.2% MWCNTs), leading to the production of combinations such as EPS + MWCNTs, EPS + CFs, and EPS + MWCNTs + CFs. Among the multicomponent mortars, the EPS + CFs combination showed the best performance, with the most standardized electromechanical response, a compressive strength of 37.68 MPa, and lower electrical resistivity compared to mortars with a single addition. In general, with the replacement of fine aggregate by EPS, no significant variations in resistivity were observed in response to cyclic loading, indicating that the greater deformations typical of EPS-based composites, although they may promote closer contact between carbonaceous additions, do not necessarily increase the sensitivity of the resulting composite. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85434 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85426 Título: Gestão da manutenção e mitigação de riscos em sistemas de proteção contra incêndio em edificações históricas por meio de BIM/FM e estruturação sistêmica da informação Autor(es): Bessa, Maycon Handerson de Oliveira Abstract: This dissertation proposes and validates an integrated methodology based on Historic Building Information Modeling (HBIM) and Facility Management (FM) to support maintenance management and risk mitigation of fire protection systems in historic buildings. The approach is oriented toward systemic information structuring, automation of maintenance processes, and decision support in operational and emergency contexts, considering the technical, constructive, and heritage-related constraints inherent to this type of built asset. The methodology was applied through a case study conducted at the José de Alencar Theatre, comprising on-site technical assessment, definition of operation and maintenance-oriented information requirements, development of a system-oriented and simplified HBIM model, semantic enrichment of building elements, structuring of maintenance plans, and automated integration of maintenance data within the modeling environment. In addition, an asset information structure centered on systems and operational loops was developed and integrated with a relational database and a visualization environment, enabling the analysis of functional interdependencies and the simulation of failure scenarios in fire detection and suppression systems. The results demonstrate the feasibility of a lean digital model, achieving a significant reduction in model complexity and data volume without compromising the information requirements necessary for operation and maintenance. The organization of assets according to functional taxonomy and operational loops enabled the identification of impact zones and enhanced response capability in critical situations. The main contributions include the development of the F2SM framework, the adoption of a maintenance-oriented strategy for decoupling geometry and information, and the proposal of systemic information structuring as a foundation for maintenance management and risk mitigation in historic buildings. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85426 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85272 Título: Blocos de concreto para vedação termicamente eficientes com resíduo de poliestireno extrudado (xps): Desenvolvimento e transferência tecnológica Autor(es): Almeida Neto, Orismildes Gomes de Abstract: The increasing generation of plastic waste and the need for more thermally and environmentally efficient construction solutions have driven research on the incorporation of polymeric materials into cementitious matrices. In this context, this study aimed to develop and evaluate concrete masonry blocks with partial volumetric replacement of coarse aggregate by extruded polystyrene (XPS) waste, analyzing their physical, mechanical, and thermal performance, as well as their potential for social application. Initially, a pilot phase was conducted with different volumetric replacement levels of coarse aggregate by XPS (25%, 30%, 35%, and 40%), in addition to a reference mixture without waste incorporation. The produced concretes were evaluated in terms of apparent density, oven-dry density, compressive strength, and ultrasonic pulse velocity. Based on the obtained results, the 35% replacement level was selected for the full-scale production phase. In the subsequent stage, concrete blocks were produced and subjected to compressive strength testing and thermal performance evaluation. Thermal analysis was carried out through experimental tests with temperature monitoring over time and estimation of apparent thermal conductivity, comparing the 35% XPS mixture with the reference mixture. Complementary thermal properties, such as specific heat, were also determined to improve the understanding of the material's thermal behavior. The results indicated a significant reduction in density with XPS incorporation, demonstrating increased material lightness. A decrease in thermal conductivity compared to conventional concrete was also observed, indicating improved thermal performance while maintaining compressive strength compatible with non-load-bearing masonry requirements, according to applicable standards. Finally, technology transfer actions were conducted within a local community, including training and demonstration of the production process. These activities indicated technical compatibility of the constructive method with the community context and potential for social application, although continuous production still depends on operational structuring and organizational development. Overall, the study demonstrates that the use of XPS waste in the production of concrete masonry blocks constitutes a technically feasible alternative, thermally more efficient than conventional material, and with potential environmental and social contributions. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85272 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85129 Título: Uma abordagem baseada em dados para a predição da resistência ao cisalhamento de vigas de concreto armado reforçadas com EB-FRP Autor(es): Freire, Francisco Lucas de Oliveira Abstract: The use of Fiber-Reinforced Polymer (FRP) has become established as a promising solution for strengthening concrete structures due to its remarkable properties, such as durability, lightweight, corrosion resistance, and speed of installation. However, the application of this material faces challenges as it is a relatively recent method, particularly regarding shear strengthening, design optimization, and the development of accurate models for strength prediction. In this context, recent publications on the use of machine learning have demonstrated the potential to overcome these hurdles, although limitations such as the scarcity of reference data and the need for robust models that capture the complexity of real structural behavior still exist. Given this background, this study aimed to propose strength prediction models for externally bonded FRP-strengthened reinforced concrete beams using linear regression models and artificial neural networks (ANN). As fundamental stages of the research, a comprehensive database was constructed from experimental studies, covering various strengthening scenarios. Through statistical analysis, dimensionality reduction was performed, identifying the most significant physical parameters and developing multiple linear regression mathematical models for shear strength prediction. Furthermore, employing machine learning techniques, an ANN was developed along with the optimization of the base model's hyperparameters. The best-performing linear model presented a mean absolute error up to 66.97% lower than international codes, with a coefficient of determination (R²) of 0.74. In the hyperparameter optimization and regularization stage of the base ANN model, predictive models were obtained with performance significantly superior to existing standards, reaching an R² in the order of 0.90. The application of LASSO regularization resulted in a model with maximum generalization capacity and physical consistency, achieving an R² of 0.92 during blind testing. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85129 2026-01-01T00:00:00Z