A rock stability problem developed during the construction of the northern tube of the St Kuzam T... more A rock stability problem developed during the construction of the northern tube of the St Kuzam Tunnel, in the town of Rijeka, Croatia and about 30 m of constructed tunnel collapsed. Experience gained from the application of high-strength, high-performance sprayed concrete (HPFRS) showed that this material is suitable for use as a primary tunnel lining.
Potential of recycled aggregate concrete (RAC) has already been acknowledged by many researchers,... more Potential of recycled aggregate concrete (RAC) has already been acknowledged by many researchers, but the focus was primarily on its mechanical and durability properties at material level. If the focus is shifted to element and whole building level, then the question can be raised; how building envelopes made from RAC behave when exposed to real environment? The present paper describes an experimental set up to monitor hygrothermal behaviour of one three-storey family house built with prefabricated ventilated sandwich wall panels made from recycled concrete and recycled brick aggregate. This type of building envelope can be classified as a heavyweight envelope. In ground-floor flat a wall in the living room facing south is analysed in terms of internal temperature evolution and humidity distribution. Conditions of indoor and outdoor environment were monitored as well. Time lag and decrement of temperature extremes were observed and these benefits can be attributed to the presence of thermal mass. Ventilation of air in cavity ensured acceptable humidity level in all characteristic layers of wall panel. Summer overheating occurred due to insufficiently shaded large transparent openings. Further step is validation of numerical model and assessing the suitability of presented envelope type to different climates. This paper indicates the great potential of RAC application in energy efficient and moisture safe building envelope design.
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2020
The construction sector, identified as one of the largest producers of construction and demolitio... more The construction sector, identified as one of the largest producers of construction and demolition waste (CDW) and one of the largest energy consumers, demands effective measures and applicable solutions to address sustainability challenges. The closed-loop recycling of CDW, integrated with the large-scale deployment of high energy performing buildings, represents a challenge for the whole construction sector, where the lack of waste efficient and energy efficient envelope systems is identified as one of the main barriers. The aim of this paper is to provide one possible solution to tackle the aforementioned issues-a highly insulated prefabricated ventilated façade panel with concrete layers produced using recycled CDW. The results of extensive research confirm that it is possible to replace a high percentage (50%) of natural coarse aggregate with recycled CDW and produce concrete with good mechanical, durability, and hygrothermal properties. Upscaling from initial research and optimisation at material level to an element level, i.e. development and testing of a ventilated façade panel, demonstrated that it is possible to produce a modular envelope system from recycled CDW that meets all performance requirements for certain construction product type (Declaration of performance and CE-marking). Moreover, the results of hygrothermal and energy consumption field monitoring at the whole building level suggest that the developed panel is suitable for use as a high-performing building envelope in real environmental conditions.
Građevinski otpad ima veliki potencijal za oporabu i recikliranje kao agregat u betonu. Odgovaraj... more Građevinski otpad ima veliki potencijal za oporabu i recikliranje kao agregat u betonu. Odgovarajuće upravljanje građevinskim otpadom bi rezultiralo efektivnim i učinkovitim korištenjem prirodnih resursa i smanjenjem utjecaja na okoliš. U ovom radu prikazan je utjecaj na okoliš inovativnog predgotovljenog zidnog panela ECO-SANDWICH® u obliku izjave o utjecaju na okoliš. Prilikom određivanja utjecaja na okoliš uključene su sve utjecajne kategorije definirane u EN 15804, a promatrano kroz cjelokupni uporabni vijek panela, od vađenja materijala, proizvodnje materijala i panela, distribucije, korištenja i razgradnje.
In Civil Engineering, the application of infrared thermography is not limited to passive investig... more In Civil Engineering, the application of infrared thermography is not limited to passive investigations of the quality of thermal insulation of building envelopes. Basic principles of the two main techniques of active infrared thermography, which are pulse thermography (PT) and Lock-in thermography (LT), are briefly recalled. In this paper, the use of passive infrared thermography technique for detecting defects in reinforced concrete structures and possible use of active thermography with post processing techniques that can be applied for defect characterization is presented.
Civil engineers are involved at every stage of a structure’s realisation and they play a key part... more Civil engineers are involved at every stage of a structure’s realisation and they play a key part in design and construction teams. Working with architects, and alongside other professions, civil engineers create conceptual designs and ensure that the structure is constructed as safe for user and sustainable. To be sustainable, structure should be environmental friendly, durable and economical. Normal expected service life prior to repair is 50 years but some of reinforced structures have the requirement to last more than 150 years. Today’s need for engineered maintenance and rehabilitation of highways, streets, bridges, airports and building structures has never been more urgent. Nevertheless, do engineers have enough knowledge for such activity? In this paper, as one example, the new subjects which are part of the curricula at Materials department at Faculty of Civil Engineering University of Zagreb, is presented.
Lagani beton sve se vise upotrebljava u građevinarstvu, pogotovo za dijelove građevina koje su iz... more Lagani beton sve se vise upotrebljava u građevinarstvu, pogotovo za dijelove građevina koje su izložene vecem okolisnom opterecenju. Cesto su ti elementi konstrukcija dodatno optereceni pa su za njih zahtjevaju i vece cvrstoce. U radu je prikazano istraživanje laganog betona s agregatom od ekspandirane gline koji ima povecane tlacne cvrstoce. Ispitano je vise sastava betona izrađenih s Liapor® ekspandiranom glinom s ciljem dobivanja betona koji zadovoljava kriterij visoke cvrstoce. Rezultati ispitivanja su pokazali da se s granulama ekspandirane gline uz dodatak silicijske prasine mogu izraditi lagani betoni visoke cvrstoce.
Potreba za energetskom neovisnošću s jedne te pritisci na okoliš s druge strane doveli su do pove... more Potreba za energetskom neovisnošću s jedne te pritisci na okoliš s druge strane doveli su do povećane potražnje i ulaganja u obnovljive izvore energije. Europska unija je postavila cilj da udio obnovljivih izvora energije u ukupnoj energetskoj potrošnji bude 20 % do 2020. godine (Direktiva o korištenju obnovljivih izvora energije 2009/28/EC), odnosno 27 % do 2030. godine (Okvir za klimatsku i energetsku politiku u razdoblju 2020.-2030. godine). Povećanje korištenja biomase kao obnovljivog izvora energije dovelo je do porasta količine pepela čija cijena odlaganja sve više raste. Stoga je potrebno osigurati njegovo održivo i učinkovito gospodarenje. Jedna od mogućnosti održivog gospodarenja pepelom jest njegova primjena u građevinskoj industriji. U radu je prikazana problematika gospodarenja pepelom iz drvne biomase (PDB), osvrt na karakterizaciju PDB-a, te preliminarni rezultati ispitivanja tlačne čvrstoće i čvrstoće na savijanje cementnih kompozita s različitim udjelima PDB-a kao zamjene za cement.
Kvaliteta betonskog zastitnog sloja od velike je važnosti za trajnost armiranobetonskih konstrukc... more Kvaliteta betonskog zastitnog sloja od velike je važnosti za trajnost armiranobetonskih konstrukcija. Zastitni sloj nedovoljne debljine i neodgovarajuce kvalitete povecava rizik korozije armature uslijed procesa karbonatizacije te djelovanja kloridnih iona. Prema tome, betonski zastitni sloj mora biti sto otporniji prodiranju agresivnih tvari. U određenoj mjeri, to se može postici upotrebom polimerom modificiranog betona za izvedbu zastitnog sloja. U radu je prikazano nekoliko primjera obnove zastitnog sloja polimerom modificiranim betonom. Nakon vizualnog pregleda te provedenih detaljnih ispitivanja, betonski elementi su sanirani zamjenom ostecenog dijela zastitnog sloja polimerom modificiranim betonom uz povecanje njegove debljine
In the recent time, several reinforced-concrete bridges in Croatia have been repaired using polym... more In the recent time, several reinforced-concrete bridges in Croatia have been repaired using polymer modified concrete. Bridges were damaged mainly due to reinforcement corrosion caused by chloride ions, carbonation and/or frost cycles. Use of polymer modified concrete as repair material is very suitable because of its numerous advantages related to permeability, wear and chemical resistance. In this paper are presented some typical examples of pavement renewals and repairs of columns and girders on several damaged reinforced concrete bridges in Croatia.
U radu su prikazane najbitnije razlike između novog Tehnickog propisa za betonske konstrukcije (T... more U radu su prikazane najbitnije razlike između novog Tehnickog propisa za betonske konstrukcije (TPBK) i do sada važeceg Pravilnika za beton i armirani beton (PBAB) koji se odnose na beton kao građevni proizvod. Bitne razlike su u oznacavanju tlacne cvrstoce betona, konzistencije svježeg betona i kontroli kvalitete betona.
Superplasticizers are nowadays often used for ready-mix concrete, but also for other purposes in ... more Superplasticizers are nowadays often used for ready-mix concrete, but also for other purposes in concrete technology. In most cases, without adding a superplasticizer to concrete, it is not possible to achieve the desired properties of fresh and hardened concrete. Properties of fresh concrete, such as slump, slump loss with time, segregation, bleeding, air content, setting time etc., depend on the type and amount of superplasticizer used, and also on its compatibility with cement. Superplasticizers reduce the water content in the mix and, consequently, increase the concrete strength. In concrete with low water cement ratio, the compatibility between the cement and superplasticizer is significant, and it depends on the chemical composition of the superplasticizer, as well as on the type and composition of the cement. In this paper, we have analysed the influence of two different types of polycarboxylate superplasticizers and three cements from different manufacturers on the concretes' properties. The properties of fresh and hardened concrete have been tested on 21 concrete mixtures, by varying three different amounts of each superplasticizer for each cement type.
The bridge over the river Bednja was built at the beginning of the 20th century as one in the ran... more The bridge over the river Bednja was built at the beginning of the 20th century as one in the range of typical bridges built at that time. Static system is two joints concrete arch over the deck slab with tie rod. Bearing structure is a slab set on the beam-and-stringer grid. Above the concrete slab, there are macadam and asphalt layer. The structure had been heavy damaged at the end of the World War II, and than renovated immediately after the war. Since than, due to the poor drainage functioning, heavy traffic loads and carbonation of concrete, the reinforcement diameters, in many places were reduced down to 20 percent and concrete cracks and spalling around reinforcement became significant. Insufficient pavement width resulted in significant damage in arch and tie rod parts probably caused by traffic accidents. In this paper the bridge renovation and strengthening of the structure are described.
Veliki broj AB mostova ima ostecenja nastala od karbonatizacije, djelovanja kloridnih iona, djelo... more Veliki broj AB mostova ima ostecenja nastala od karbonatizacije, djelovanja kloridnih iona, djelovanja smrzavanja i odmrzavanja te mekih voda. U radu se predlaže nacin sanacije ostecenih dijelova te izvedba kolnicke konstrukcije od specijalnog polimer modificiranog betona kao zamjena za hidroizolaciju i asfaltni kolnik.
This paper presents ventilated prefabricated wall panel which utilises recycled construction and ... more This paper presents ventilated prefabricated wall panel which utilises recycled construction and demolition waste (CDW) and mineral wool produced using innovative and sustainable technology for reduction of primary energy consumption in building stock. The results of EU Eco-innovation research project titled ECO- SANDWICH represents a significant improvement over the existing prefabricated wall panel products, aligning itself with the mandatory targets of the EU Energy Performance of Buildings Directive - EPBD, its Recast EPBD II. and with Waste Framework Directive targets. The concept incorporates three priorities of the eco-innovation call ; it uses recycled material to create innovative sustainable building product which contributes to greening the business of SMEs through decreasing their environmental impact accompanied by the use of less non-renewable or natural resources, and energy efficiency to Nearly zero energy building (nZEB). ECO-SANDWICH project encourages the re-use a...
A rock stability problem developed during the construction of the northern tube of the St Kuzam T... more A rock stability problem developed during the construction of the northern tube of the St Kuzam Tunnel, in the town of Rijeka, Croatia and about 30 m of constructed tunnel collapsed. Experience gained from the application of high-strength, high-performance sprayed concrete (HPFRS) showed that this material is suitable for use as a primary tunnel lining.
Potential of recycled aggregate concrete (RAC) has already been acknowledged by many researchers,... more Potential of recycled aggregate concrete (RAC) has already been acknowledged by many researchers, but the focus was primarily on its mechanical and durability properties at material level. If the focus is shifted to element and whole building level, then the question can be raised; how building envelopes made from RAC behave when exposed to real environment? The present paper describes an experimental set up to monitor hygrothermal behaviour of one three-storey family house built with prefabricated ventilated sandwich wall panels made from recycled concrete and recycled brick aggregate. This type of building envelope can be classified as a heavyweight envelope. In ground-floor flat a wall in the living room facing south is analysed in terms of internal temperature evolution and humidity distribution. Conditions of indoor and outdoor environment were monitored as well. Time lag and decrement of temperature extremes were observed and these benefits can be attributed to the presence of thermal mass. Ventilation of air in cavity ensured acceptable humidity level in all characteristic layers of wall panel. Summer overheating occurred due to insufficiently shaded large transparent openings. Further step is validation of numerical model and assessing the suitability of presented envelope type to different climates. This paper indicates the great potential of RAC application in energy efficient and moisture safe building envelope design.
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2020
The construction sector, identified as one of the largest producers of construction and demolitio... more The construction sector, identified as one of the largest producers of construction and demolition waste (CDW) and one of the largest energy consumers, demands effective measures and applicable solutions to address sustainability challenges. The closed-loop recycling of CDW, integrated with the large-scale deployment of high energy performing buildings, represents a challenge for the whole construction sector, where the lack of waste efficient and energy efficient envelope systems is identified as one of the main barriers. The aim of this paper is to provide one possible solution to tackle the aforementioned issues-a highly insulated prefabricated ventilated façade panel with concrete layers produced using recycled CDW. The results of extensive research confirm that it is possible to replace a high percentage (50%) of natural coarse aggregate with recycled CDW and produce concrete with good mechanical, durability, and hygrothermal properties. Upscaling from initial research and optimisation at material level to an element level, i.e. development and testing of a ventilated façade panel, demonstrated that it is possible to produce a modular envelope system from recycled CDW that meets all performance requirements for certain construction product type (Declaration of performance and CE-marking). Moreover, the results of hygrothermal and energy consumption field monitoring at the whole building level suggest that the developed panel is suitable for use as a high-performing building envelope in real environmental conditions.
Građevinski otpad ima veliki potencijal za oporabu i recikliranje kao agregat u betonu. Odgovaraj... more Građevinski otpad ima veliki potencijal za oporabu i recikliranje kao agregat u betonu. Odgovarajuće upravljanje građevinskim otpadom bi rezultiralo efektivnim i učinkovitim korištenjem prirodnih resursa i smanjenjem utjecaja na okoliš. U ovom radu prikazan je utjecaj na okoliš inovativnog predgotovljenog zidnog panela ECO-SANDWICH® u obliku izjave o utjecaju na okoliš. Prilikom određivanja utjecaja na okoliš uključene su sve utjecajne kategorije definirane u EN 15804, a promatrano kroz cjelokupni uporabni vijek panela, od vađenja materijala, proizvodnje materijala i panela, distribucije, korištenja i razgradnje.
In Civil Engineering, the application of infrared thermography is not limited to passive investig... more In Civil Engineering, the application of infrared thermography is not limited to passive investigations of the quality of thermal insulation of building envelopes. Basic principles of the two main techniques of active infrared thermography, which are pulse thermography (PT) and Lock-in thermography (LT), are briefly recalled. In this paper, the use of passive infrared thermography technique for detecting defects in reinforced concrete structures and possible use of active thermography with post processing techniques that can be applied for defect characterization is presented.
Civil engineers are involved at every stage of a structure’s realisation and they play a key part... more Civil engineers are involved at every stage of a structure’s realisation and they play a key part in design and construction teams. Working with architects, and alongside other professions, civil engineers create conceptual designs and ensure that the structure is constructed as safe for user and sustainable. To be sustainable, structure should be environmental friendly, durable and economical. Normal expected service life prior to repair is 50 years but some of reinforced structures have the requirement to last more than 150 years. Today’s need for engineered maintenance and rehabilitation of highways, streets, bridges, airports and building structures has never been more urgent. Nevertheless, do engineers have enough knowledge for such activity? In this paper, as one example, the new subjects which are part of the curricula at Materials department at Faculty of Civil Engineering University of Zagreb, is presented.
Lagani beton sve se vise upotrebljava u građevinarstvu, pogotovo za dijelove građevina koje su iz... more Lagani beton sve se vise upotrebljava u građevinarstvu, pogotovo za dijelove građevina koje su izložene vecem okolisnom opterecenju. Cesto su ti elementi konstrukcija dodatno optereceni pa su za njih zahtjevaju i vece cvrstoce. U radu je prikazano istraživanje laganog betona s agregatom od ekspandirane gline koji ima povecane tlacne cvrstoce. Ispitano je vise sastava betona izrađenih s Liapor® ekspandiranom glinom s ciljem dobivanja betona koji zadovoljava kriterij visoke cvrstoce. Rezultati ispitivanja su pokazali da se s granulama ekspandirane gline uz dodatak silicijske prasine mogu izraditi lagani betoni visoke cvrstoce.
Potreba za energetskom neovisnošću s jedne te pritisci na okoliš s druge strane doveli su do pove... more Potreba za energetskom neovisnošću s jedne te pritisci na okoliš s druge strane doveli su do povećane potražnje i ulaganja u obnovljive izvore energije. Europska unija je postavila cilj da udio obnovljivih izvora energije u ukupnoj energetskoj potrošnji bude 20 % do 2020. godine (Direktiva o korištenju obnovljivih izvora energije 2009/28/EC), odnosno 27 % do 2030. godine (Okvir za klimatsku i energetsku politiku u razdoblju 2020.-2030. godine). Povećanje korištenja biomase kao obnovljivog izvora energije dovelo je do porasta količine pepela čija cijena odlaganja sve više raste. Stoga je potrebno osigurati njegovo održivo i učinkovito gospodarenje. Jedna od mogućnosti održivog gospodarenja pepelom jest njegova primjena u građevinskoj industriji. U radu je prikazana problematika gospodarenja pepelom iz drvne biomase (PDB), osvrt na karakterizaciju PDB-a, te preliminarni rezultati ispitivanja tlačne čvrstoće i čvrstoće na savijanje cementnih kompozita s različitim udjelima PDB-a kao zamjene za cement.
Kvaliteta betonskog zastitnog sloja od velike je važnosti za trajnost armiranobetonskih konstrukc... more Kvaliteta betonskog zastitnog sloja od velike je važnosti za trajnost armiranobetonskih konstrukcija. Zastitni sloj nedovoljne debljine i neodgovarajuce kvalitete povecava rizik korozije armature uslijed procesa karbonatizacije te djelovanja kloridnih iona. Prema tome, betonski zastitni sloj mora biti sto otporniji prodiranju agresivnih tvari. U određenoj mjeri, to se može postici upotrebom polimerom modificiranog betona za izvedbu zastitnog sloja. U radu je prikazano nekoliko primjera obnove zastitnog sloja polimerom modificiranim betonom. Nakon vizualnog pregleda te provedenih detaljnih ispitivanja, betonski elementi su sanirani zamjenom ostecenog dijela zastitnog sloja polimerom modificiranim betonom uz povecanje njegove debljine
In the recent time, several reinforced-concrete bridges in Croatia have been repaired using polym... more In the recent time, several reinforced-concrete bridges in Croatia have been repaired using polymer modified concrete. Bridges were damaged mainly due to reinforcement corrosion caused by chloride ions, carbonation and/or frost cycles. Use of polymer modified concrete as repair material is very suitable because of its numerous advantages related to permeability, wear and chemical resistance. In this paper are presented some typical examples of pavement renewals and repairs of columns and girders on several damaged reinforced concrete bridges in Croatia.
U radu su prikazane najbitnije razlike između novog Tehnickog propisa za betonske konstrukcije (T... more U radu su prikazane najbitnije razlike između novog Tehnickog propisa za betonske konstrukcije (TPBK) i do sada važeceg Pravilnika za beton i armirani beton (PBAB) koji se odnose na beton kao građevni proizvod. Bitne razlike su u oznacavanju tlacne cvrstoce betona, konzistencije svježeg betona i kontroli kvalitete betona.
Superplasticizers are nowadays often used for ready-mix concrete, but also for other purposes in ... more Superplasticizers are nowadays often used for ready-mix concrete, but also for other purposes in concrete technology. In most cases, without adding a superplasticizer to concrete, it is not possible to achieve the desired properties of fresh and hardened concrete. Properties of fresh concrete, such as slump, slump loss with time, segregation, bleeding, air content, setting time etc., depend on the type and amount of superplasticizer used, and also on its compatibility with cement. Superplasticizers reduce the water content in the mix and, consequently, increase the concrete strength. In concrete with low water cement ratio, the compatibility between the cement and superplasticizer is significant, and it depends on the chemical composition of the superplasticizer, as well as on the type and composition of the cement. In this paper, we have analysed the influence of two different types of polycarboxylate superplasticizers and three cements from different manufacturers on the concretes' properties. The properties of fresh and hardened concrete have been tested on 21 concrete mixtures, by varying three different amounts of each superplasticizer for each cement type.
The bridge over the river Bednja was built at the beginning of the 20th century as one in the ran... more The bridge over the river Bednja was built at the beginning of the 20th century as one in the range of typical bridges built at that time. Static system is two joints concrete arch over the deck slab with tie rod. Bearing structure is a slab set on the beam-and-stringer grid. Above the concrete slab, there are macadam and asphalt layer. The structure had been heavy damaged at the end of the World War II, and than renovated immediately after the war. Since than, due to the poor drainage functioning, heavy traffic loads and carbonation of concrete, the reinforcement diameters, in many places were reduced down to 20 percent and concrete cracks and spalling around reinforcement became significant. Insufficient pavement width resulted in significant damage in arch and tie rod parts probably caused by traffic accidents. In this paper the bridge renovation and strengthening of the structure are described.
Veliki broj AB mostova ima ostecenja nastala od karbonatizacije, djelovanja kloridnih iona, djelo... more Veliki broj AB mostova ima ostecenja nastala od karbonatizacije, djelovanja kloridnih iona, djelovanja smrzavanja i odmrzavanja te mekih voda. U radu se predlaže nacin sanacije ostecenih dijelova te izvedba kolnicke konstrukcije od specijalnog polimer modificiranog betona kao zamjena za hidroizolaciju i asfaltni kolnik.
This paper presents ventilated prefabricated wall panel which utilises recycled construction and ... more This paper presents ventilated prefabricated wall panel which utilises recycled construction and demolition waste (CDW) and mineral wool produced using innovative and sustainable technology for reduction of primary energy consumption in building stock. The results of EU Eco-innovation research project titled ECO- SANDWICH represents a significant improvement over the existing prefabricated wall panel products, aligning itself with the mandatory targets of the EU Energy Performance of Buildings Directive - EPBD, its Recast EPBD II. and with Waste Framework Directive targets. The concept incorporates three priorities of the eco-innovation call ; it uses recycled material to create innovative sustainable building product which contributes to greening the business of SMEs through decreasing their environmental impact accompanied by the use of less non-renewable or natural resources, and energy efficiency to Nearly zero energy building (nZEB). ECO-SANDWICH project encourages the re-use a...
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