Search

Your search keyword '"Radeka, Miroslava"' showing total 40 results
Start Over Author "Radeka, Miroslava"
40 results on '"Radeka, Miroslava"'

1. Effects of soft water attack on Portland and natural zeolite blended cements

Author

Milović Tiana, Rudić Ognjen, Furgan Saeeda Omran, Radeka Miroslava, Malešev Mirjana, Radonjanin Vlastimir, Baloš Sebastian, and Laban Mirjana

Subjects
ca-clinoptilolite, compressive strength, deionised water, ftir spectroscopy, leaching, xrd analysis, Chemical engineering, TP155-156, Chemical industries, HD9650-9663
Abstract

The durability of concrete infrastructure is related to the properties of the applied concrete and the effects of the aggressive external environment on it. When concrete is directly exposed to soft water, the leaching of calcium ions from hardened cement or cement-based pastes occurs, causing reduction in strength and further deterioration of the concrete structure. This paper presents the experimental results of soft water attack effects on phase composition and compressive strength of blended cement pastes, when cement is replaced with 0, 10, 20 and 30% of natural zeolite. In order to simulate soft water attack in laboratory conditions, paste specimens were exposed to leaching in deionised water up to 180 days. The evaluation of the changes in phase composition (ettringite, portlandite, calcium silicate hydrate gel) due to calcium ion leaching was made based on X-ray diffraction analysis, Fourier-transform infrared spectroscopy and paste compressive strength tests. The presence of portlandite and ettringite after 180 days of exposure to deionised water indicates that leaching did not influence the stability of the hydration products in blended cement pastes. Moreover, blended cement paste with 10% of natural zeolite had a higher compressive strength than the reference one.

Published
2021
Full Text
View/download PDF

3. Hydration process and compressive strength of cement pastes containing natural zeolite

Author

Radeka Miroslava, Milović Tiana, Malešev Mirjana, Radonjanin Vlastimir, and Laban Mirjana

Subjects
natural zeolite, cement paste, hydration products, xrd, ftir, mercury intrusion porosimetry, compressive strength, Engineering (General). Civil engineering (General), TA1-2040
Abstract

This paper presents the results of the study examining the effect of natural zeolite from Igroš, Serbia, on the hydration and compressive strength of Portland cement based pastes, in which a part of cement has been replaced by natural zeolite. The experimental part comprises three stages. In the first stage, the chemical composition of natural zeolite and the textural properties of both natural zeolite and Portland cement have been examined. In the second stage, Portland cement based pastes incorporating 0%, 10%, 20% and 30% per weight of natural zeolite have been prepared and cured for 28 and 60 days. Finally, mineralogical properties and compressive strength of pastes have been examined. The products of hydration and relative changes of portlandite consumption throughout hydration process (28 and 60 days) have been studied by the means of X-ray diffraction and Fourier transform infrared spectroscopy. Additionally, mercury intrusion porosimetry has been used to characterise pore structure.

Published
2016
Full Text
View/download PDF

4. Construction products performances and basic requirements for fire safety of facades in energy rehabilitation of buildings

Author

Laban Mirjana Đ., Radonjanin Vlastimir S., Malešev Mirjana M., and Radeka Miroslava M.

Subjects
buiding renewal, building materials, facades, fire safety, Engineering (General). Civil engineering (General), TA1-2040
Abstract

Construction product means any product or kit which is produced and placed on the market for incorporation in a permanent manner in construction works, or parts thereof, and the performance of which has an effect on the performance of the construction works with respect to the basic requirements for construction works. Safety in case of fire and Energy economy and heat retention represent two among seven basic requirements which building has to meet according to contemporary technical rules on planning and construction. Performances of external walls building materials (particularly reaction to fire) could significantly affect to fire spread on the façade and other building parts. Therefore, façade shaping and materialization in building renewal process, has to meet the fire safety requirement, as well as the energy requirement. Brief survey of fire protection regulations development in Serbia is presented in the paper. Preventive measures for fire risk reduction in building façade energy renewal are proposed according to contemporary fire safety requirements.

Published
2015
Full Text
View/download PDF

6. Determination of the photocatalytic activity of TiO2 coatings on clay roofing tile substrates methylene blue as model pollutant

Author

Skapin Andrea S., Petrović Snežana B., Radeka Miroslava M., Lončar Eva S., Ranogajec Jonjaua G., and Rudić Ognjen Lj.

Subjects
TiO2 coatings, clay roofing tile, photocatalytic activity, Technology (General), T1-995
Abstract

The photocatalytically active mesoporous coatings, based on titanium dioxide sols (Degussa), of the fired clay roofing tiles substrate were prepared by using poly(ethylene glycol) (PEG) M-600 and M-4000, as the structure directing agents. The coatings were deposited using spray technique followed by thermal treatment. Photocatalytic activity of the TiO2 coatings was evaluated by aqueous solution of methylene blue as model dye, deposited on the top of the coatings, after irradiation with UV light. The results were compared with the photocatalytic efficiency of some commercial self-cleaning products (clay roofing tiles, glass). The newly design coatings showed an interesting decolourisation performance (over 30 % after 24 h). It appeared that the procedure of photocatalytic activity determination, in the case of porous substrates, should be renewed by a preadsorption process.

Published
2009
Full Text
View/download PDF

8. Uticaj primene prirodnog zeolita na trajnost reparaturnih cementnih maltera

Author

Radeka, Miroslava, Malešev, Mirjana, Radonjanin, Vlastimir, Ilić, Biljana, Kukaras, Danijel, Lukić, Ivan, Milović, Tiana, Radeka, Miroslava, Malešev, Mirjana, Radonjanin, Vlastimir, Ilić, Biljana, Kukaras, Danijel, Lukić, Ivan, and Milović, Tiana

Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja mogućnosti primene prirodnog zeolita iz Srbije, za zamenu dela cementa u cementnim malterima, i mogućnost primene datih maltera kao reparaturnih nekonstrukcijskih i/ili konstrukcijskih materijala. Kako bi se preciznije odredili produkti pucolanske reakcije, urađeno je ispitivanje faznog sastava očvrslih pasta. Na očvrslim malterima ispitani su: čvrstoća pri pritisku, kapilarno upijanje vode, izluživanje, prianjanje za betonsku podlogu, kao i svojstva trajnosti. Postavljeni ciljevi su ispunjeni, a rezultati ispitivanja su pokazali da malteri koji sadrže do 20% prirodnog zeolita kao mineralnog dodatka, ispunjavaju uslove za konstrukcijski reparaturni malter prema EN 1504-3., The dissertation presents the results of own experimental research of the possibility of using natural zeolite from Serbia, for a partial replacement of the cement in cement mortars, and the possibility of using these mortars as nonstructural and/or structural repair materials. The phase composition of hardened cement pastes was examined for a more precise determination of pozzolanic reaction products. The following properties of hardened mortars were tested and analyzed: compressive strength, capillary water absorption, leaching, bond strength, as well as durability. The set goals were met, and the test results showed that mortars containing up to 20% of natural zeolite as a mineral additive meet the requirements for structural repair mortar according to EN 1504-3.

Published
2021

10. Agricultural biomass ash in civil engineering - from energy to sustainable development

Author

Barišić, Ivana, Netinger Grubeša, Ivanka, Dokšanović, Tihomir, Draganić, Hrvoje, Malešev, Mirjana, Šupić, Slobodan, Radeka, Miroslava, and Radonjanin, Vlastimir

Subjects
Biomaterials, Environment, New and advanced materials, Sustainable development, agricultural biomass ash, energy, civil engineering, sustainable development
Abstract

Every year in the world millions of tons of harvest residues are generated, such as corn stalks and corn cob blanks, wheat, soy and rice straw, sunflowers and rice husk. Those harvest residues can be used as a replacement for fossil fuels and represent a renewable energy source. Ash, which is generated by the combustion of harvest residues, is usually deposited in landfills, causing environment pollution and potential human health risks. Such a state is a consequence of non-existent bio-ash management and the absence of pollution control. In order to promote biomass as an energy source, available quantities of agricultural biomass in Croatia and Serbia are presented. Heating power of various harvest residues is determined and compared to the heating power of standard energy sources. The possibilities of using biomass ash as waste material in the building industry are outlined. Different kind of biomass ashes can be successfully used to replace cement in mortars and concrete and have a positive influence on geotechnical properties of soil. Preliminary results of ash application suggest that these ashes exhibit the potential for use in the building industry, but due to differences in their characteristics, each of them needs to be investigated in more detail.

Published
2019

12. This title is unavailable for guests, please login to see more information.

Author

Radeka, Miroslava, Martinov, Milan, Malešev, Mirjana, Radonjanin, Vlastimir, Markov, Siniša, Grdić, Zoran, Maoduš, Nikola, Radeka, Miroslava, Martinov, Milan, Malešev, Mirjana, Radonjanin, Vlastimir, Markov, Siniša, Grdić, Zoran, and Maoduš, Nikola

Abstract

Istraživanje u okviru doktorske disertacije obuhvata analizu mogućnosti proizvodnje i primene biokompozitnih termoizolacionih ploča zasnovanih na nusproizvodima poljoprivredne proizvodnje i micelijuma gljive bukovače kao vezivnog sredstva. Ciljevi istraživanja su razvoj metode za proizvodnju biokompozitnih termoizolacionih materijala i utvrđivanje morfoloških, fizičko-hemijskih, mehaničkih i higrotermičkih svojstava biokompozita. U skladu sa rezultatima istraživanja i zaključcima da je moguće proizvesti i koristiti biokompozitni termoizolacioni materijal zasnovan na biomasi i micelijumu gljiva izvedena je analiza energetske efikasnosti i životnog ciklusa materijala. Rezultati istraživanja predstavljaju značajnu polaznu osnovu za proizvodnju i dalje unapređenje biokompozitnih termoizolacionih materijala u građevinarstvu, sa pozitivnom ocenom micelijuma gljiva kao vezivnog sredstva., Research in the thesis is focused on development and utilisation of biocomposite thermal insulation panels based on agricultural biomass and oyster mushroom mycelium as a binding agent. The goals of the research are development of production method of biocomposite thermal insulation panels and determination of morphological, physical-chemical, mechanical and hygrothermal properties of the biocomposite. Energy efficiency and life cycle assessment were conducted in accordance with the research results and conclusions that it is possible to manufacture and use the biocomposite thermal insulation panels based on biomass and mushroom mycelium. The research results represent significant starting point for manufacturing and further improvement of biocomposite thermal insulation panels used in civil engineering and confirm the use of mycelium as a binding agent.

Published
2019

13. Primena pepela nastalog sagorevanjem žetvenih ostataka kao mineralnog dodatka u cementnim kompozitima

Author

Radonjanin, Vlastimir, Malešev, Mirjana, Radeka, Miroslava, Stanisavljević, Nemanja, Netinger-Grubeša, Ivanka, Šupić, Slobodan, Radonjanin, Vlastimir, Malešev, Mirjana, Radeka, Miroslava, Stanisavljević, Nemanja, Netinger-Grubeša, Ivanka, and Šupić, Slobodan

Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja mogućnosti primjene biopepela, nastalog sagorjevanjem žetvenih ostataka, kao mineralnog dodatka u cementnim kompozitima: malterima i betonima. Istraživanje je zasnovano na komparativnoj analizi 27 vrsta maltera u kojima je varirana vrsta biopepela i vrsta sitnozrnog agregata i 12 vrsta betona koje se razlikuju u vrsti veziva i u krupnom agregatu. Na očvrslom malteru su ispitani: konzistencija, čvrstoća pri pritisku i kapilarno upijanje vode, a na očvrslom betonu ispitivani su kapilarno upijanje vode, skupljanje pri sušenju, čvrstoća pri pritisku, dinamički modul elastičnosti, otpornost na habanje, vodonepropustljivost i čvrstoća na savijanje. Istaknuto je da se primjenom biopepela kao zamjene dijela cementa mogu dobiti konstrukcijski malteri i betoni, odnosno betoni sa zadovoljavajućim fizičkim i mehaničkim karakteristikama., The dissertation presents the results of an own experimental research on the possibility of using biomass ash as a mineral additive in cement composites: mortar and concrete. The research is based on a comparative analysis of 27 types of mortars in which the type of biomass ash and the type of fine-grained aggregate were varied, as well as 12 types of concrete that differ in the type of binder and coarse aggregate. Following properties were tested on hardened mortars: consistency, compressive strength and capillary water absorption, and on hardened concrete: capillary water absorption, drying shrinkage, compressive strength, dinamic modulus of elasticity, wear resistance, waterpermeability and flexural strength. It was pointed out that biomass ash can be used as a replacement of a part of cement, thereby obtaining satisfactory physical and mechanical characteristics.

Published
2019

14. Развој и примена биокомпозитног плочастог термоизолационог материјала на бази биомасе и мицелијума гљива

Author

Radeka, Miroslava, Martinov, Milan, Malešev, Mirjana, Radonjanin, Vlastimir, Markov, Siniša, Grdić, Zoran, Radeka, Miroslava, Martinov, Milan, Malešev, Mirjana, Radonjanin, Vlastimir, Markov, Siniša, and Grdić, Zoran

Abstract

Истраживање у оквиру докторске дисертације обухвата анализу могућности производње и примене биокомпозитних термоизолационих плоча заснованих на нуспроизводима пољопривредне производње и мицелијума гљиве буковаче као везивног средства. Циљеви истраживања су развој методе за производњу биокомпозитних термоизолационих материјала и утврђивање морфолошких, физичко-хемијских, механичких и хигротермичких својстава биокомпозита. У складу са резултатима истраживања и закључцима да је могуће произвести и користити биокомпозитни термоизолациони материјал заснован на биомаси и мицелијуму гљива изведена је анализа енергетске ефикасности и животног циклуса материјала. Резултати истраживања представљају значајну полазну основу за производњу и даље унапређење биокомпозитних термоизолационих материјала у грађевинарству, са позитивном оценом мицелијума гљива као везивног средства., Istraživanje u okviru doktorske disertacije obuhvata analizu mogućnosti proizvodnje i primene biokompozitnih termoizolacionih ploča zasnovanih na nusproizvodima poljoprivredne proizvodnje i micelijuma gljive bukovače kao vezivnog sredstva. Ciljevi istraživanja su razvoj metode za proizvodnju biokompozitnih termoizolacionih materijala i utvrđivanje morfoloških, fizičko-hemijskih, mehaničkih i higrotermičkih svojstava biokompozita. U skladu sa rezultatima istraživanja i zaključcima da je moguće proizvesti i koristiti biokompozitni termoizolacioni materijal zasnovan na biomasi i micelijumu gljiva izvedena je analiza energetske efikasnosti i životnog ciklusa materijala. Rezultati istraživanja predstavljaju značajnu polaznu osnovu za proizvodnju i dalje unapređenje biokompozitnih termoizolacionih materijala u građevinarstvu, sa pozitivnom ocenom micelijuma gljiva kao vezivnog sredstva., Research in the thesis is focused on development and utilisation of biocomposite thermal insulation panels based on agricultural biomass and oyster mushroom mycelium as a binding agent. The goals of the research are development of production method of biocomposite thermal insulation panels and determination of morphological, physical-chemical, mechanical and hygrothermal properties of the biocomposite. Energy efficiency and life cycle assessment were conducted in accordance with the research results and conclusions that it is possible to manufacture and use the biocomposite thermal insulation panels based on biomass and mushroom mycelium. The research results represent significant starting point for manufacturing and further improvement of biocomposite thermal insulation panels used in civil engineering and confirm the use of mycelium as a binding agent.

Published
2019

17. Sulfatna otpornost betona na bazi recikliranog agregata

Author

Malešev, Mirjana, Radeka, Miroslava, Radonjanin, Vlastimir, Topličić-Ćurčić, Gordana, Grdić, Zoran, Bulatović, Vesna, Malešev, Mirjana, Radeka, Miroslava, Radonjanin, Vlastimir, Topličić-Ćurčić, Gordana, Grdić, Zoran, and Bulatović, Vesna

Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja sulfatne otpornosti betona sa recikliranim agregatom. Istraživanje je zasnovano na komparativnoj analizi dve grupe betona koje se razlikuju u krupnom agregatu, a u okviru kojih su varirani dve vrste cementa i dva vodocementna faktora. Sulfatna otpornost je proveravana nakon 3 i 6 meseci boravka u 5% Na2SO4 i u 5% MgSO4. Na očvrslom betonu ispitivani su kapilarno upijanje vode, promena dužine uzoraka, čvrstoća pri pritisku i urađene su mikrostrukturne analize: MIP, SEM, BSE/EDS, XRD i FTIR. Istaknuto je da se primenom krupnog agregata od recikliranog betona i veziva odgovarajućeg mineraloškog sastava mogu dobiti konstrukcijski betoni, odnosno betoni sa zadovoljavajućim mehaničkim karakteristikama, ali i sa zadovoljavajućom trajnošću sa aspekta sulfatne korozije., This paper presents the experimental research results of the sulphate resistance of concrete with recycled aggregate. The research is based on a comparative analysis of two groups of concrete that differ in coarse aggregate types. Within these two concrete groups, two types of cement of the same class and two water/cement ratios have been varied. Sulphate resistance was examined after 3 and 6 months of immersion in 5% Na2SO4 and 5% MgSO4. Capillary water absorption, sample length change and compressive strength were studied in hardened concrete and the following microstructural analyzes were performed: MIP, SEM, BSE/EDS, XRD and FTIR. It has been found that structural concrete with apppropriate mechanical properties as well as with satisfactory durability from the aspect of sulphate corrosion can be obtained by combination of a coarse recycled concrete aggregate and a binder of an appropriate mineralogical composition.

Published
2017

18. Uticaj termički i mehanohemijski aktivirane kaolinske gline na mehanička svojstva i strukturu cementnih kompozita

Author

Ilić, Biljana, Radonjanin, Vlastimir, Malešev, Mirjana, Grdić, Zoran, Radeka, Miroslava, Mitrović, Aleksandra, Ilić, Biljana, Ilić, Biljana, Radonjanin, Vlastimir, Malešev, Mirjana, Grdić, Zoran, Radeka, Miroslava, Mitrović, Aleksandra, and Ilić, Biljana

Abstract

Predmet ovog istraživanja je razvoj nove generacije mineralnih dodataka, dobijenih termičkom i mehanohemijskom aktivacijom kaolinske gline i ispitivanje svojstava kompozita, u kojima je deo portland cementa zamenjen dobijenim pucolanskim materijalima, metakaolinom i amorfnim kaolinom, za različite režime nege. Rezultati su pokazali da su termička i mehanohemijska aktivacija kaolinske gline jednako pogodne metode za dobijanje pucolanskih materijala. Pozitivni efekti na čvrstoće pri pritisku postižu se primenom do 30 % metakaolina u kompozitima pri normalnom režimu nege, a uz dodatno mlevenje, sadržaj metakaolina se može povećati do 40 %, uz dodatak CH. Amorfni kaolin se može primeniti u kompozitima, sa stepenom zamene portland cementa do 10 %, pri normalnom i autoklaviranom režimu nege., The subject of this research is development of a new generation of mineral admixtures, obtained by thermal and mechanochemical activation of kaolin clay, and testing of the properties of the cement based composites, where a part of the portland cement is replaced by pozzolanic materials, metakaolin and amorphous kaolin, for different curing conditions. The results showed that thermal and mechanochemical activation of kaolin clay were equally suitable for obtaining pozzolanic materials. Positive effects on the compressive strength could be achieved by using up to 30 % of MK, and with additional grinding after thermal activation, content of MK could be increased up to 40 %, with the addition of CH, under the normal curing conditions. Amorphous kaolin could be used in composites with a cement replacement level of 10 %, under the normal and autoclave curing conditions.

Published
2016

19. Uticaj termički i mehanohemijski aktivirane kaolinske gline na mehanička svojstva i strukturu cementnih kompozita

Author

Radonjanin, Vlastimir, Malešev, Mirjana, Grdić, Zoran, Radeka, Miroslava, Mitrović, Aleksandra, Ilić, Biljana, Radonjanin, Vlastimir, Malešev, Mirjana, Grdić, Zoran, Radeka, Miroslava, Mitrović, Aleksandra, and Ilić, Biljana

Abstract

Predmet ovog istraživanja je razvoj nove generacije mineralnih dodataka, dobijenih termičkom i mehanohemijskom aktivacijom kaolinske gline i ispitivanje svojstava kompozita, u kojima je deo portland cementa zamenjen dobijenim pucolanskim materijalima, metakaolinom i amorfnim kaolinom, za različite režime nege. Rezultati su pokazali da su termička i mehanohemijska aktivacija kaolinske gline jednako pogodne metode za dobijanje pucolanskih materijala. Pozitivni efekti na čvrstoće pri pritisku postižu se primenom do 30 % metakaolina u kompozitima pri normalnom režimu nege, a uz dodatno mlevenje, sadržaj metakaolina se može povećati do 40 %, uz dodatak CH. Amorfni kaolin se može primeniti u kompozitima, sa stepenom zamene portland cementa do 10 %, pri normalnom i autoklaviranom režimu nege., The subject of this research is development of a new generation of mineral admixtures, obtained by thermal and mechanochemical activation of kaolin clay, and testing of the properties of the cement based composites, where a part of the portland cement is replaced by pozzolanic materials, metakaolin and amorphous kaolin, for different curing conditions. The results showed that thermal and mechanochemical activation of kaolin clay were equally suitable for obtaining pozzolanic materials. Positive effects on the compressive strength could be achieved by using up to 30 % of MK, and with additional grinding after thermal activation, content of MK could be increased up to 40 %, with the addition of CH, under the normal curing conditions. Amorphous kaolin could be used in composites with a cement replacement level of 10 %, under the normal and autoclave curing conditions.

Published
2016

21. Characterization of the substrates from two cultural-heritage sites and a preparation of model substrates: Karakterizacija gradbenih materialov iz dveh objektov kulturne dediščine in priprava modelnih materialov

Author

Ducman, Vilma, Kramar, Sabina, Radeka, Miroslava, Ranogajec, Jonjaua, Velkavrh, Edo, and Vucetic, Snezana

Abstract

In this study the microstructural characteristics of the materials selected from two cultural-heritage sites (the Dornava Manor, Slovenia, and the Bač Fortress, Serbia) and of the model samples - the control and aged ones - were investigated. The samples were characterized by means of mercury intrusion porosimetry (MIP) and total-specific-area analysis (BET). A good agreement was achieved between the samples of the brick and mortar from the Bač Fortress,or the samples of the natural stone and render from the Dornava Manor, and the corresponding model samples. Prispevek obravnava mikrostrukturne lastnosti izbranih materialov iz dveh objektov kulturne dediščine (dvorec Dornava v Sloveniji in trdnjava Bač v Srbiji) ter modelnih materialov - kontrolnih in staranih. Vzorce smo preiskali z živosrebrno porozimetrijo in plinsko sorpcijo. Med vzorci iz objektov kulturne dediščine in modelnimi vzorci smo dosegli dobro ujemanje, tako v primeru opeke in malte s trdnjave Bač kot naravnega kamna in ometa z dvorca Dornava.

Published
2014

22. Strength and microstructural analysis of concrete incorporating ash from sunflower seed shells combustion.

Author

Grubeša, Ivanka N., Radeka, Miroslava, Malešev, Mirjana, Radonjanin, Vlastimir, Gojević, Anita, and Siddique, Rafat

Subjects
*SUNFLOWER seeds, *FLY ash, *COMPRESSIVE strength, *CONSTRUCTION materials, *CONCRETE construction
Abstract

The aim of the study involves determining the added value of shells of sunflower seeds ash (SSA) as a mineral admixture in concrete and the effects/mechanisms through which it affects the concrete microstructure. The chemical effect of this type of ash was estimated by examining its chemical composition, pozzolanic activity index, and SEM investigation while its physical effect was observed at the level of concrete with ash incorporated. Four concrete mixtures with different shares of cement replacement by ash were prepared (0, 5, 7.5, and 10%). The water to binder ratio was 0.5, and binder content 400 kg/m3 in all mixtures. The properties of fresh and hardened concrete with ash incorporated were compared with the corresponding properties of the reference concrete. The results indicate that SSA achieved all the known possible effects of mineral admixtures; filler effect, heterogonous nucleation effect, dilution effect, and a certain degree of chemical effect. However, replacing more than 5% of cement mass with SSA will adversely affect mechanical properties of concrete. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

24. Komparativna analiza osnovnih svojstava konstrukcijskih betona spravljenih sa različitim vrstama lakih agregata

Author

Malešev, Mirjana, Radonjanin, Vlastimir, Radeka, Miroslava, Trivunić, Milan, Ignjatović, Ivan, Malešev, Mirjana, Radonjanin, Vlastimir, Radeka, Miroslava, Trivunić, Milan, and Ignjatović, Ivan

Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja na osnovu kojih je izvršena komparativna analiza uticaja različitih vrsta lakih agregata i vrste i količine cementa na osnovna fizičko-mehanička svojstva lakoagregatnih betona. Takođe, analizirana je i mogućnost zamene dela cementa mineralnim dodacima u cilju smanjenja negativnih uticaja proizvodnje betona na životnu sredinu. Rezultati su pokazali da je primenom svih analiziranih vrsta agregata moguće dobiti konstrukcijski lakoagregatni beton, čak i sa manjim količinama cementa, odnosno sa zamenom dela cementa mineralnim dodacima, kao i da je moguće uspostaviti pouzdane korelacione veze između pojedinih svojstava betona i primenjenih komponentnih materijala., In dissertation are presented results of own experimental research of a comparative analysis of the impact of different types of lightweight aggregates and the type and quantity of cement on basic physical and mechanical properties of structural lightweight concrete. Also, the possibility of replacing part of cement with mineral admixtures is analyzed in order to reduce the negative impact of concrete production on the environment. The results showed that it is possible to obtain structural lightweight aggregate concrete with all types of lightweight aggregates and even with lower quantities of cement or with a replacement of part of a cement with mineral admixtures. Also, it is possible to establish a reliable correlation between certain properties of concrete and used component materials.

Published
2015

33. PHOTOCATALYTIC AND SUPERHYDROPHILIC PHENOMENA OF TIO2 COATED CLAY ROOFING TILES.

Author

Ranogajec, Jonjaua, Radeka, Miroslava, Bačkalić, Zoran, Škapin, Andreja, and Zorić, Dmitar

Subjects
*PHOTOCATALYSIS, *TITANIUM dioxide, *COATING processes, *ABSORPTION, *RHODAMINE B, *ENERGY consumption
Abstract

The coating procedure of clay roofing tiles was obtained using a simple spraying technique of a laboratory made TiO2 suspension. This was followed by a thermal treatment at 120/150 C ( = 30 min). The defined mass % of TiO2, grain size value of TiO2 and its crystal form were the main characteristics of the designed suspensions. The tile samples were studied in their progressive ageing with exposure to visible light and water rinsing procedure. The photocatalytic activity of the coatings was determined after visible irradiation (sun and artificial light) of the defined intensity (I = 80 W/m2) through the measurements of the absorption values of the rhodamine B, while the results of the superhydrophilic property were obtained based on the measurements of the water contact angle. Considering the energy consumption, it was shown that the tile products based on the new designed suspension could be produced in already existing industrial dryers using the existing waste heat in the industrial line. [ABSTRACT FROM AUTHOR]

Published
2010
Full Text
View/download PDF

34. Evaluation of the effect of lichens on ceramic roofing tiles by scanning electron microscopy and energy‐dispersive spectroscopy analyses

Author

Kiurski, Jelena S., Ranogajec, Jonjaua G., Ujhelji, Agnesš L., Radeka, Miroslava M., and Bokorov, Miloš T.

Abstract

The effect of the actions of some lichens on the quality of ceramic roofing tiles was investigated in view of textural and microstructural changes considering their biocorrosion resistance. Two types (extruded and pressed) of the real ceramic roofing tiles aged 6 to 10 years, as well as the ceramic model systems formed with the additives of the specific chemical composition Cu‐slag powder (10 wt%) and CuO powder (1 wt%), treated with various concentrations of oxalic acid (0.01 wt%, 0.1 wt%, and 4 wt%) were investigated. The thalli of lichen (Verrucaria nigrescens) growth on ceramic roofing tile were examined by scanning electron microscopy (SEM) and energy‐dispersive spectroscopy (EDS). Investigation by SEM and EDS gave information regarding the ultrastructure characteristics of the thallus and the lichen‐ceramic tile contact zone, allowing the observation of the hyphal penetration and filling up of the fissures and cracks by the lichens' hyphae. The CuO as the raw mixture additive changed the quality of the surface of the ceramic model systems as it has increased resistance to oxalic acid actions. The textural changes in the ceramic model systems and the formation of the identified destructive crystal phase, whewellite, were slowed down. The fundamental interactions between lichens and ceramic materials of the model systems have been identified as physico‐chemical processes based on oxalic acid actions, which could cause ceramic matrix deterioration and consequently aging of ceramic roofing tile systems.

Published
2005
Full Text
View/download PDF

35. Uticaj primene prirodnog zeolita na trajnost reparaturnih cementnih maltera

Author

Milović, Tiana, Radeka, Miroslava, Malešev, Mirjana, Radonjanin, Vlastimir, Ilić, Biljana, Kukaras, Danijel, and Lukić, Ivan

Subjects
Natural zeolite, fly ash, repair mortar, compresive strength, bond strength,XRD, FTIR, leaching, durability, Prirodni zeolit, elektrofilterski pepeo, reparaturni malter,čvrstoća pri pritisku, athezija, XRD, FTIR, izluživanje, trajnost
Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnogistraživanja mogućnosti primene prirodnog zeolita iz Srbije, zazamenu dela cementa u cementnim malterima, i mogućnost primenedatih maltera kao reparaturnih nekonstrukcijskih i/ilikonstrukcijskih materijala. Kako bi se preciznije odredili produktipucolanske reakcije, urađeno je ispitivanje faznog sastava očvrslihpasta. Na očvrslim malterima ispitani su: čvrstoća pri pritisku,kapilarno upijanje vode, izluživanje, prianjanje za betonsku podlogu,kao i svojstva trajnosti. Postavljeni ciljevi su ispunjeni, a rezultatiispitivanja su pokazali da malteri koji sadrže do 20% prirodnogzeolita kao mineralnog dodatka, ispunjavaju uslove za konstrukcijskireparaturni malter prema EN 1504-3., The dissertation presents the results of own experimental research of thepossibility of using natural zeolite from Serbia, for a partial replacement of thecement in cement mortars, and the possibility of using these mortars as nonstructuraland/or structural repair materials. The phase composition ofhardened cement pastes was examined for a more precise determination ofpozzolanic reaction products. The following properties of hardened mortarswere tested and analyzed: compressive strength, capillary water absorption,leaching, bond strength, as well as durability. The set goals were met, and thetest results showed that mortars containing up to 20% of natural zeolite as amineral additive meet the requirements for structural repair mortar accordingto EN 1504-3.

Published
2021

36. Primena pepela nastalog sagorevanjem žetvenih ostataka kao mineralnog dodatka u cementnim kompozitima

Author

Šupić, Slobodan, Radonjanin, Vlastimir, Malešev, Mirjana, Radeka, Miroslava, Stanisavljević, Nemanja, and Netinger-Grubeša, Ivanka

Subjects
skupljanje, mineral binder, Biopepeo, minralni dodatak, cementni kompoziti, reciklirani agregat od betona, čvrstoća pri pritisku, kapilarno upijanje, skupljanje, reciklirani agregat od betona, čvrstoća pri pritisku, minralni dodatak, Biomass ash, mineral binder, cement composites, recycled concrete aggregate, compressive strength, capillary absorption, shrinkage, compressive strength, kapilarno upijanje, shrinkage, capillary absorption, recycled concrete aggregate, Biopepeo, cementni kompoziti, cement composites, Biomass ash
Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja mogućnosti primjene biopepela, nastalog sagorjevanjem žetvenih ostataka, kao mineralnog dodatka u cementnim kompozitima: malterima i betonima. Istraživanje je zasnovano na komparativnoj analizi 27 vrsta maltera u kojima je varirana vrsta biopepela i vrsta sitnozrnog agregata i 12 vrsta betona koje se razlikuju u vrsti veziva i u krupnom agregatu. Na očvrslom malteru su ispitani: konzistencija, čvrstoća pri pritisku i kapilarno upijanje vode, a na očvrslom betonu ispitivani su kapilarno upijanje vode, skupljanje pri sušenju, čvrstoća pri pritisku, dinamički modul elastičnosti, otpornost na habanje, vodonepropustljivost i čvrstoća na savijanje. Istaknuto je da se primjenom biopepela kao zamjene dijela cementa mogu dobiti konstrukcijski malteri i betoni, odnosno betoni sa zadovoljavajućim fizičkim i mehaničkim karakteristikama., The dissertation presents the results of an own experimental research on the possibility of using biomass ash as a mineral additive in cement composites: mortar and concrete. The research is based on a comparative analysis of 27 types of mortars in which the type of biomass ash and the type of fine-grained aggregate were varied, as well as 12 types of concrete that differ in the type of binder and coarse aggregate. Following properties were tested on hardened mortars: consistency, compressive strength and capillary water absorption, and on hardened concrete: capillary water absorption, drying shrinkage, compressive strength, dinamic modulus of elasticity, wear resistance, waterpermeability and flexural strength. It was pointed out that biomass ash can be used as a replacement of a part of cement, thereby obtaining satisfactory physical and mechanical characteristics.

Published
2019

37. Razvoj i primena biokompozitnog pločastog termoizolacionog materijala na bazi biomase i micelijuma gljiva

Author

Maoduš, Nikola, Radeka, Miroslava, Martinov, Milan, Malešev, Mirjana, Radonjanin, Vlastimir, Markov, Siniša, and Grdić, Zoran

Subjects
termoizolacioni paneli, wheat straw, biomass, конопља, Bio-composite, thermal insulation panels, wheat straw, hemp, mycelium, biomass, properties, konoplja, micelijum, својства, hemp, Биокомпозит, biomasa, Биокомпозит, термоизолациони панели, пшенична слама, конопља, мицелијум, биомаса, својства, Biokompozit, properties, термоизолациони панели, пшенична слама, биомаса, Biokompozit, termoizolacioni paneli, pšenična slama, konoplja, micelijum, biomasa, svojstva, mycelium, мицелијум, svojstva, pšenična slama, Bio-composite, thermal insulation panels
Abstract

Истраживање у оквиру докторске дисертације обухвата анализу могућности производње и примене биокомпозитних термоизолационих плоча заснованих на нуспроизводима пољопривредне производње и мицелијума гљиве буковаче као везивног средства. Циљеви истраживања су развој методе за производњу биокомпозитних термоизолационих материјала и утврђивање морфолошких, физичко-хемијских, механичких и хигротермичких својстава биокомпозита. У складу са резултатима истраживања и закључцима да је могуће произвести и користити биокомпозитни термоизолациони материјал заснован на биомаси и мицелијуму гљива изведена је анализа енергетске ефикасности и животног циклуса материјала. Резултати истраживања представљају значајну полазну основу за производњу и даље унапређење биокомпозитних термоизолационих материјала у грађевинарству, са позитивном оценом мицелијума гљива као везивног средства., Istraživanje u okviru doktorske disertacije obuhvata analizu mogućnosti proizvodnje i primene biokompozitnih termoizolacionih ploča zasnovanih na nusproizvodima poljoprivredne proizvodnje i micelijuma gljive bukovače kao vezivnog sredstva. Ciljevi istraživanja su razvoj metode za proizvodnju biokompozitnih termoizolacionih materijala i utvrđivanje morfoloških, fizičko-hemijskih, mehaničkih i higrotermičkih svojstava biokompozita. U skladu sa rezultatima istraživanja i zaključcima da je moguće proizvesti i koristiti biokompozitni termoizolacioni materijal zasnovan na biomasi i micelijumu gljiva izvedena je analiza energetske efikasnosti i životnog ciklusa materijala. Rezultati istraživanja predstavljaju značajnu polaznu osnovu za proizvodnju i dalje unapređenje biokompozitnih termoizolacionih materijala u građevinarstvu, sa pozitivnom ocenom micelijuma gljiva kao vezivnog sredstva., Research in the thesis is focused on development and utilisation ofbiocomposite thermal insulation panels based on agricultural biomass andoyster mushroom mycelium as a binding agent. The goals of the research aredevelopment of production method of biocomposite thermal insulation panelsand determination of morphological, physical-chemical, mechanical andhygrothermal properties of the biocomposite. Energy efficiency and life cycleassessment were conducted in accordance with the research results andconclusions that it is possible to manufacture and use the biocompositethermal insulation panels based on biomass and mushroom mycelium. Theresearch results represent significant starting point for manufacturing andfurther improvement of biocomposite thermal insulation panels used in civilengineering and confirm the use of mycelium as a binding agent.

Published
2019

38. Sulfatna otpornost betona na bazi recikliranog agregata

Author

Bulatović, Vesna, Malešev, Mirjana, Radeka, Miroslava, Radonjanin, Vlastimir, Topličić-Ćurčić, Gordana, and Grdić, Zoran

Subjects
Sulfate resistance, recycled concrete agregate compresive strength,expansion, capillary adsorption, porosity, SEM, XRD, FTIR, ekspanzija, porosity, recycled concrete agregate compresive strength, XRD, reciklirani agregat od betona, Sulfate resistance, kapilarno upijanje, expansion, FTIR, capillary adsorption, poroznost, SEM, čvrstoća pripritisku, Sulfatna otpornost, reciklirani agregat od betona, čvrstoća pripritisku, ekspanzija, kapilarno upijanje, poroznost, SEM, XRD, FTIR, Sulfatna otpornost
Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnogistraživanja sulfatne otpornosti betona sa recikliranim agregatom.Istraživanje je zasnovano na komparativnoj analizi dve grupe betona kojese razlikuju u krupnom agregatu, a u okviru kojih su varirani dve vrstecementa i dva vodocementna faktora. Sulfatna otpornost je proveravananakon 3 i 6 meseci boravka u 5% Na2SO4 i u 5% MgSO4. Na očvrslom betonuispitivani su kapilarno upijanje vode, promena dužine uzoraka, čvrstoćapri pritisku i urađene su mikrostrukturne analize: MIP, SEM, BSE/EDS,XRD i FTIR. Istaknuto je da se primenom krupnog agregata od recikliranogbetona i veziva odgovarajućeg mineraloškog sastava mogu dobitikonstrukcijski betoni, odnosno betoni sa zadovoljavajućim mehaničkimkarakteristikama, ali i sa zadovoljavajućom trajnošću sa aspektasulfatne korozije., This paper presents the experimental research results of the sulphate resistance ofconcrete with recycled aggregate. The research is based on a comparative analysis oftwo groups of concrete that differ in coarse aggregate types. Within these two concretegroups, two types of cement of the same class and two water/cement ratios have beenvaried. Sulphate resistance was examined after 3 and 6 months of immersion in 5%Na2SO4 and 5% MgSO4. Capillary water absorption, sample length change andcompressive strength were studied in hardened concrete and the followingmicrostructural analyzes were performed: MIP, SEM, BSE/EDS, XRD and FTIR. It hasbeen found that structural concrete with apppropriate mechanical properties as well aswith satisfactory durability from the aspect of sulphate corrosion can be obtained bycombination of a coarse recycled concrete aggregate and a binder of an appropriatemineralogical composition.

Published
2017

39. Effect of thermal and mechanochemical activated kaolin clay onthe mechanical properties and structure of the cement basedcomposites

Author

Ilić, Biljana, Radonjanin, Vlastimir, Malešev, Mirjana, Grdić, Zoran, Radeka, Miroslava, and Mitrović, Aleksandra

Subjects
metakaolin, kaolin clay, kaolinska glina, termička aktivacija, mechanochemical activation, thermal activation, amorphous kaolinite, pozzolan, mehanohemijska aktivacija, supersonični aerotunel, amorfni kaolin, Cementni kompoziti, termička aktivacija, mehanohemijska aktivacija, kaolinska glina, metakaolin, amorfni kaolin, Cementni kompoziti, Cement based composites, Cement based composites, thermal activation,mechanochemical activation, kaolin clay, metakaolin,amorphous kaolinite, pozzolan
Abstract

Predmet ovog istraživanja je razvoj nove generacijemineralnih dodataka, dobijenih termičkom imehanohemijskom aktivacijom kaolinske gline i ispitivanjesvojstava kompozita, u kojima je deo portland cementazamenjen dobijenim pucolanskim materijalima,metakaolinom i amorfnim kaolinom, za različite režimenege. Rezultati su pokazali da su termička i mehanohemijskaaktivacija kaolinske gline jednako pogodne metode zadobijanje pucolanskih materijala. Pozitivni efekti načvrstoće pri pritisku postižu se primenom do 30 %metakaolina u kompozitima pri normalnom režimu nege, a uzdodatno mlevenje, sadržaj metakaolina se može povećati do40 %, uz dodatak CH. Amorfni kaolin se može primeniti ukompozitima, sa stepenom zamene portland cementa do 10 %,pri normalnom i autoklaviranom režimu nege., The subject of this research is development of a new generationof mineral admixtures, obtained by thermal andmechanochemical activation of kaolin clay, and testing of theproperties of the cement based composites, where a part of theportland cement is replaced by pozzolanic materials, metakaolinand amorphous kaolin, for different curing conditions. Theresults showed that thermal and mechanochemical activation ofkaolin clay were equally suitable for obtaining pozzolanicmaterials. Positive effects on the compressive strength could beachieved by using up to 30 % of MK, and with additional grindingafter thermal activation, content of MK could be increased up to40 %, with the addition of CH, under the normal curingconditions. Amorphous kaolin could be used in composites witha cement replacement level of 10 %, under the normal andautoclave curing conditions.

Published
2016

40. A comparative analysis of the basic properties of structural concrete made with different types of lightweight aggregates

Author

Lukić, Ivan, Malešev, Mirjana, Radonjanin, Vlastimir, Radeka, Miroslava, Trivunić, Milan, and Ignjatović, Ivan

Subjects
Lightweight aggregate, lightweight aggregate concrete, mineral admixture,compresive strength, modulus of elasticity, Laki agregat, lakoagregatni beton, mineralni dodatak, čvrstoća pri pritisku, modul elstičnosti
Abstract

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja na osnovu kojih je izvršena komparativna analiza uticaja različitih vrsta lakih agregata i vrste i količine cementa na osnovna fizičko-mehanička svojstva lakoagregatnih betona. Takođe, analizirana je i mogućnost zamene dela cementa mineralnim dodacima u cilju smanjenja negativnih uticaja proizvodnje betona na životnu sredinu. Rezultati su pokazali da je primenom svih analiziranih vrsta agregata moguće dobiti konstrukcijski lakoagregatni beton, čak i sa manjim količinama cementa, odnosno sa zamenom dela cementa mineralnim dodacima, kao i da je moguće uspostaviti pouzdane korelacione veze između pojedinih svojstava betona i primenjenih komponentnih materijala., In dissertation are presented results of own experimental research of acomparative analysis of the impact of different types of lightweightaggregates and the type and quantity of cement on basic physical andmechanical properties of structural lightweight concrete. Also, the possibilityof replacing part of cement with mineral admixtures is analyzed in order toreduce the negative impact of concrete production on the environment. Theresults showed that it is possible to obtain structural lightweight aggregateconcrete with all types of lightweight aggregates and even with lowerquantities of cement or with a replacement of part of a cement with mineraladmixtures. Also, it is possible to establish a reliable correlation betweencertain properties of concrete and used component materials.

Published
2015

Catalog

Books, media, physical & digital resources
See catalog results