Revista ALCONPAT

RA V14 N3, Message from the Editor in Chief (September – December, 2024)

Pedro Castro Borges — 2024-09-01

LATIN AMERICAN JOURNAL OF QUALITY CONTROL, PATHOLOGY AND CONSTRUCTION RECOVERY

http://www.revistaalconpat.org

It is a source of satisfaction and joy for the ALCONPAT Journal team to see the third issue of our fourteenth year published.

The objective of the Revista ALCONPAT (RA) is the publication of citable production (basic or applied research, and reviews), documentary research and case studies, related to the themes of our association, i.e. quality control, pathology and recovery of constructions.

In this V14 N3 of the Alconpat Journal, the Editorial Committee is pleased to have as Guest Editors Doctors Roberto Christ (President of Alconpat Brazil) and Enio Pazini (President of Alconpat International), who have done an excellent job in the selection, evaluation and approval of the works that appear in this issue. These works responded to the call for best works sent to the Brazilian Congress of Construction Pathology (CBPat 2024) under the theme of "Strategies, methods, materials and technology to confer durability and sustainability to concrete infrastructure".

We are confident that the articles in this issue will be an important reference for those readers involved in issues of evaluation and characterization of materials, elements and structures. We thank the authors participating in this issue for their willingness and effort to submit quality articles and meet the established deadlines.

Fourteen years after starting operations, our performance as Alconpat Journal was finally rewarded with our inclusion in one of the two best indexes for journals such as Elsevier's Scopus. We already have a modest impact factor (0.3), which I am sure will increase thanks to you, our readers, and the quality of our articles. Our membership in Scopus has its historic beginning on December 29, 2022, the date on which we received approval from Elsevier. We hope during 2025, when we will celebrate 15 years of being on the air, to apply to Journal Citation Reports, which is the index with the highest international coverage and quality. These are reasons for celebration for our community that has made a scientific investment in our journal waiting for moments like this. Congratulations to all.

By the Editorial Board

Pedro Castro Borges

Editor in Chief

Comparison of mechanical behavior of slabs reinforced with GFRP and steel

Roberto Christ — 2024-09-01

The objective of this study is to evaluate the mechanical behavior of GRFP in massive concrete slabs. The use of glass fiber reinforced polymer (GFRP) rebars in construction design has been an alternative technique to provide more durable structures. However, there is a need to evaluate the behavior of GFRP reinforced slabs under flexure and to compare the service state (SS) and ultimate service state (USS) of the loaded element. Thus, reinforced concrete slabs of varying thicknesses were constructed with steel and GFRP rebars. Results show that the applied load for maximum span deflection of the GFRP slab under SS was 50% lower than for the one with steel reinforcement. The maximum span deflection of the GFRP slab under USS was also 282% larger than for steel rebars reinforcement.

Behavior prediction of reinforced concrete beams shear strengthened with CFRP

Palloma Borges Soares — 2024-09-01

This work presents the computational modeling of reinforced concrete beams, strengthened to shear with carbon fiber-reinforced polymers (CFRP), using the finite element method (FEM) and the customized ANSYS software, version 19.2. It is important to emphasize that contact elements and bilinear cohesive zone models provided by ANSYS were used to model the concrete-reinforcement interface. These models were used to identify the modes of premature failure caused by the debonding of the reinforcement, which causes poor use of the CFRP's resistance properties. The structural elements used in this analysis were twelve simply supported reinforced concrete beams, without and with shear reinforcement using CFRP, which were experimentally tested by Khalifa (1999). From the analysis of the results, it was observed that the developed numerical models were able to accurately predict the behavior of the simulated beams, both in terms of load-displacement, as well as the load and rupture mode of the beams.

Formation of incipient anodes in localized mortar repairs with the addition of rice husk silica

Igor Rossi Remenche — 2024-09-01

The objective of this work was to investigate how incipient anodes can be detected and monitored in localized repair areas using mortars with added rice husk silica. Three repair conditions were tested on prismatic specimens: without repair, with repair without rice husk silica addition, and with rice husk silica addition in the mortar. Corrosion potential and electrical resistivity tests were conducted. The corrosion potential test showed no variation along the bar, while the electrical resistivity test showed varied values depending on the repaired and non-repaired zones. It was concluded that adding rice husk silica to the mortar made the corrosion potential more electronegative due to the greater difference in electrical resistivity compared to the substrate, contributing to the formation of incipient anodes.

Experimental analysis of the tensile behavior of concrete reinforced with Brazilian glass textile

Joici Rizzo — 2024-09-01

In this study, the mechanical behavior of concrete structures reinforced with one and two layers of the Brazilian glass textile “AR-360” was verified through direct tensile tests. The analysis of the mechanical behavior of the structures was performed with stress-strain curves, evaluating the transition points of the formed stages, rupture mode, rupture stress and strain, as well as an analysis comparing experimental results with analytics. Regarding the results, there was a structural inability of the pieces reinforced with a layer of glass textile. In the samples in which reinforcement with two layers of the aforementioned material was evaluated, the three stages present in the stress-strain curves were correctly identified, as predicted in the literature for the structures evaluated.

Crack detection in buildings using the YOLO v8 network

Weiglas Soriano Ribeiro — 2024-09-01

The objective of this study is to develop and apply deep neural networks for the automation of crack detection in buildings. The methodology involved training the YOLO v8 network with images collected from the internet, aiming to identify and locate cracks in real time. The model obtained 80% accuracy in validation with images not used in training, despite performance limitations in Google Collab. These limitations included restrictions on the execution environment, and the model is specific to cracks. The originality of the tool lies in its relevance for the automated detection of cracks, with the potential to extend to other pathological manifestations. It is concluded that the application of deep neural networks offers an efficient solution for the identification of problems in buildings.

Pathological manifestations in a historic building: post-fire scenario at Casarão dos Fabricantes

Maria Helena C. M. Bezerra — 2024-09-01

The objective of this study is to document the pathological manifestations of the Casarão dos Fabricantes, one of the oldest buildings in Fortaleza, which was severely damaged by a major fire in 2020. Despite its historical significance, there are no records detailing the condition of the building either before or after the fire. The internal walls and two facades were the only construction elements that were not destroyed by the fire. The survey of the pathological manifestations was conducted by visual assessment and infrared thermography, revealing different degradation processes across the evaluated structures and providing a systematic view of the extent of the damage to the building. Mapping this damage provided an integrated approach, offering a scientific basis to support the restoration process.

Mapping building facades using panoramic images captured by Unmanned Aerial Vehicle (UAV)

Marcelo Bordinhão — 2024-09-01

This work aims to verify the building pathologies of DTIC’s building front (Diretoria de Tecnologia da Informação e Comunicação at Federal University of Pampa – Alegrete/RS, Brazil) by using an Unmanned Aerial Vehicle (UAV). The study was conducted before and six months after its maintenance. Images and inspection records were used to elaborate the Damage Maps and the Grid Method for pathologies quantifications. The comparison of the Damage Maps before and after maintenance has revealed that the intervention (paint) was not efficient, since it has disguised temporarily the anomalies without correcting them. The use of UAV proved to be a good tool for building inspections, providing effective diagnosis, time-saving and security for the operator without working at height.

Fundamentally understanding carbonation-induced corrosion of steel in environmentally friendly concretes

Cristhiana Albert — 2024-09-01

Reducing greenhouse gas emissions in concrete production is crucial to achieve sustainability goals. One of the primary solutions is employing environmentally friendly cements with lower clinker content, such as those containing supplementary cementitious materials. However, concretes produced with some of these cements are vulnerable to fast carbonation, which raises durability concerns regarding corrosion of the steel reinforcement. While traditional approaches focus on preventing concrete carbonation and corrosion initiation, evidence shows that corrosion rates of steel in carbonated concrete do not necessarily compromise durability. In this context, the fundamental understanding of the kinetics of carbonation-induced corrosion must be improved, considering the role of the concrete pore solution, pore structure, and moisture content, as discussed in this paper. Open questions and promising approaches to clarify them are also discussed. Based on this knowledge, corrosion propagation can be properly included in the service life design of reinforced concrete structures, reconciling the goals for both sustainable and durable structures.