Bojan Milovanović

Analysis of Thermal Properties of Cement Paste During Setting and Hardening

An experimental investigation is made in order to study changes of thermal properties of hardening cement paste. Using a hot disc principle for determination of thermal properties, specific heat capacity, effusivity and thermal conductivity are analyzed during first 4 days of hydration. Specific heat capacity value changed only slightly during hydration. Thermal conductivity decreased with the progress of hydration 20% compared to initial value. Hydration process was monitored using ultrasonic pulse velocity (UPV) test. A discussion of results is made taking into account porous nature of cement paste and transformation of liquid and hardened phases i.e. water and clinker minerals, into hardened structure.The motivation for conducted research is improvement of numerical models for calculating temperature changes in mass concrete structures using hydration dependant thermal properties. Also, another field of application could be the quality control of cement based materials.

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.

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.