Ivana Banjad Pečur

Review of Active IR Thermography for Detection and Characterization of Defects in Reinforced Concrete

Active thermography methods enable structural investigations of reinforced concrete elements taking into account many different testing problems. The goal of this review is to provide an overview on the state-of-the-art regarding the use of active infrared thermography (IRT) for detection and characterization of defects in reinforced concrete. The paper will provide the physical background, equipment being used, as well as post-processing methods that are used to analyse sequences of thermograms. This work also presents the fields of applicability of IRT with a focus on the aspects related to reinforced concrete structures, as well as the advantages, limitations and potential sources of errors of IRT employment. Additionally previous non-destructive testing (NDT) studies that employed thermography techniques with natural excitation are briefly presented. A review of the future trends of thermal imaging are also included in this work. It can be concluded that while IRT is a useful tool for the characterisation of defects in the building sector, there is great prospect for the development of more advanced, effective and accurate approaches that will employ a combination of thermography approaches.

Evaluating rebar corrosion damage in RC structures exposed to marine environment using neural network

Data on the effects of the environmental conditions, structure, and properties of concrete onto the degree of damage caused by chloride-induced steel corrosion have been gathered on three concrete structures in an Adriatic marine environment. The damages were classified into six categories based on the type of remedial work necessary. An artificial neural network for feature categorization was used as a tool for classification of the degree of damage. The model was successfully trained and validated for the range of data from investigated bridges. The interactions and sensitivities of the principal parameters were investigated. The model indicates that the exposure and microclimate conditions are rated higher than the porosity, strength, water–cement ratio, cement content, and cement type. The model could be useful for planning the maintenance of investigated structures and design of remedial works.

Residual Mechanical Properties of Concrete Made with Crushed Clay Bricks and Roof Tiles Aggregate after Exposure to High Temperatures

This paper presents the residual mechanical properties of concrete made with crushed bricks and clay roof tile aggregates after exposure to high temperatures. One referent mixture and eight mixtures with different percentages of replacement of natural aggregate by crushed bricks and roof tiles are experimentally tested. The properties of the concrete were measured before and after exposure to 200, 400, 600 and 800 °C. In order to evaluate the basic residual mechanical properties of concrete with crushed bricks and roof tiles after exposure to high temperatures, ultrasonic pulse velocity is used as a non-destructive test method and the results are compared with those of a destructive method for validation. The mixture with the highest percentage of replacement of natural aggregate by crushed brick and roof tile aggregate has the best physical, mechanical, and thermal properties for application of such concrete in precast concrete elements exposed to high temperatures.

The methodology for defect quantification in concrete using IR thermography

AbstractThis paper presents a procedure for detecting and quantifying defects in reinforced concrete structures by using the method of active infrared thermography (IRT). For quantitative analysis, a methodology of thermal stimulation of concrete specimens and post-processing of the gathered data was developed. Presented methodology uses principles of step heating (SH) thermography, pulsed phase (PPT) thermography, principal component thermography (PCT) and correlation operators technique. A short descriptions of the post-processing methods used in the research is also provided in the paper. All three post-processing methods i.e. PPT, PCT and correlation operators technique have shown the possibility to enhance the defect detection in concrete structures in comparison to raw thermograms. According to the data accessible to the authors, in presented research, correlation operators and PCT post-processing techniques are being successfully used for the first time for defect detection within concrete structur...

Comparative full-scale fire performance testing of ETICS systems

U ovom radu prikazano je ispitivanje fasadnih sustava u stvarnoj veličini. Ispitivanje je provedeno s ciljem usporedbe ponašanja ETICS sustava s različitim toplinsko izolacijskim slojem (goriva izolacija, goriva izolacija s protupožarnom barijerom od negorivog materijala, negoriva izolacija) u uvjetima požara. Uzorci su izrađeni i ispitani u skladu s normom BS 8414-1:2002, a provedena su i dodatna mjerenja kako bi se dobili bitni podaci koji omogućuju bolje razumijevanje ponašanja ETICS sustava u požaru.A full-scale test has been performed to determine fire performance of different ETICS systems (combustible insulation, combustible insulation with fire barrier, noncombustible insulation). Test specimens were constructed and tested according to BS 8414-1:2002, while additional measurements were also conducted to obtain valuable information for better understanding of fire performance of systems used. U ovom radu prikazano je ispitivanje fasadnih sustava u stvarnoj velicini. Ispitivanje je provedeno s ciljem usporedbe ponasanja ETICS sustava s razlicitim toplinsko izolacijskim slojem (goriva izolacija, goriva izolacija s protupožarnom barijerom od negorivog materijala, negoriva izolacija) u uvjetima požara. Uzorci su izrađeni i ispitani u skladu s normom BS 8414-1:2002, a provedena su i dodatna mjerenja kako bi se dobili bitni podaci koji omogucuju bolje razumijevanje ponasanja ETICS sustava u požaru.

Usporedba ponašanja različitih ETICS sustava u uvjetima požara ispitivanjem u stvarnoj veličini

U ovom radu prikazano je ispitivanje fasadnih sustava u stvarnoj veličini. Ispitivanje je provedeno s ciljem usporedbe ponašanja ETICS sustava s različitim toplinsko izolacijskim slojem (goriva izolacija, goriva izolacija s protupožarnom barijerom od negorivog materijala, negoriva izolacija) u uvjetima požara. Uzorci su izrađeni i ispitani u skladu s normom BS 8414-1:2002, a provedena su i dodatna mjerenja kako bi se dobili bitni podaci koji omogućuju bolje razumijevanje ponašanja ETICS sustava u požaru.A full-scale test has been performed to determine fire performance of different ETICS systems (combustible insulation, combustible insulation with fire barrier, noncombustible insulation). Test specimens were constructed and tested according to BS 8414-1:2002, while additional measurements were also conducted to obtain valuable information for better understanding of fire performance of systems used. U ovom radu prikazano je ispitivanje fasadnih sustava u stvarnoj velicini. Ispitivanje je provedeno s ciljem usporedbe ponasanja ETICS sustava s razlicitim toplinsko izolacijskim slojem (goriva izolacija, goriva izolacija s protupožarnom barijerom od negorivog materijala, negoriva izolacija) u uvjetima požara. Uzorci su izrađeni i ispitani u skladu s normom BS 8414-1:2002, a provedena su i dodatna mjerenja kako bi se dobili bitni podaci koji omogucuju bolje razumijevanje ponasanja ETICS sustava u požaru.