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Pojava prslina dovodi do narušavanja strukture zaštitnog sloja betona i do ubrzanja transporta štetnih materija, čime utiču na trajnost armiranobetonskih (AB) konstrukcija. Kroz sveobuhvatni pregled literature, zaključeno je da deterioracija AB konstrukcija izazvana karbonatizacijom predstavlja jedan od glavnih problema trajnosti širom sveta. Za potrebe ispitivanja, u okviru doktorske disertacije, spravljeni su referentni beton, beton sa 50% letećeg pepela (LP) i beton sa 100% recikliranog agregata (RA). Analizirani su postojeći modeli predikcije dubine karbonatizacije i predložena je njihova modifikacija u slučaju betona sa RA i LP. Ustanovljena je veza između karbonatizacione otpornosti i čvrstoće pri pritisku na osnovu koje je izvršena analiza upotrebnog veka kroz definisanje debljine zaštitnog sloja različitih vrsta betona. Za potrebe ispitivanja uticaja prslina na upotrebni vek spravljeni su uzorci sa 5 različitih širina prslina (0.05, 0.10, 0.15, 0.20 i 0.30 mm) kao i referentni uzorci bez prslina. Na kraju, predloženo je ograničenje napona u armaturi čime se omogućava da celokupni upotrebni vek (period inicijacije i propagacije) AB konstrukcija zadovolji propisane zahteve trajnosti.

Održive zgrade su istovremeno otporne, bezbedne, zdrave, energetski efikasne, trajne i komforne za korišćenje. U okviru sprovedenih istraživanja razvijen je i formiran strateški model kojim se rešava problem istovremene integracije više zahteva/aspekata (energetska efikasnost, trajnost, bezbednost od požara) u procesu obnove fasada/zgrada. Validacijom predloženog modela kroz studiju slučaja je dokazano da se njegovom upotrebom omogućuje: metodološki pristup unapređenju stanja postojećih zgrada u pravcu održivog izgrađenog okruženja, a da se pri tom zadrže nasleđene vrednosti i prednosti postojećih zgrada; detekcija, lociranje i geometrijska karakterizacija pukotina na fasadama primenom novokreiranog poluautomatizovanog digitalnog alata; procena rizika od požara, primenom novokreirane metodologije, jedinstvene na našim prostorima i u skladu sa najnovijim trendovima u oblasti analize rizika; dostupnost podataka i informacija potrebnih za detaljnu analizu stvarnog stanja i celokupni proces planiranja i projektovanja obnove postojećih zgrada, putem dosijea zgrade, koji predstavlja jedan od izlaznih rezultata modela; kao i formiranje okvira za dalji razvoj modela za različite nivoe obnove od pojedinačnih zgrada do kompletnih blokova zgrada i naselja u celini.&nbsp, Sustainable buildings are resistant, safe, healthy, energy efficient, durable and comfortable to use. Within the scope of the conducted research, a strategic model was developed and formed, which solves the problem of the simultaneous integration of several requirements/aspects (energy efficiency, durability, fire safety) in the process of renewal of facades/buildings. Validation of the proposed model through a case study proved that its use enables: a methodological approach to improving the condition of existing buildings in the direction of a sustainable built environment, while maintaining the inherited values and advantages ofexisting buildings; detection, location and geometric characterization of facade cracks using a newly created semi-automated digital tool; fire risk assessment, using a newly created methodology, unique in our region and in accordance with the latest trends in the field of risk analysis; the availability of data and information needed for a detailed facade assessment and the overall process of planning and designing the renewal of existing buildings, through the „building file“, which is one of the output of the model; as well as forming a framework for further development of models for different levels of renovation from individual buildings to complete blocks of buildings and settlements as a whole.

Спроведено истраживање решава проблем одређивања ризика од појаве преливањаводе преко саобраћајнице у профилу путног пропуста на бујичном сливу применомпробабилистичког модела процене ризика и хидролошко-хидрауличког моделаанализиране појаве. Формирање новог хидролошко-хидрауличког модела проценеризика, који укљујучује више нових приступа моделовању различитих процесакоји доводе до анализиране појаве, представља један од доприноса спроведеногистраживања. Новоформирани модел процене ризика је примењен на 67 бетонскихпропуста на експерименталној деоници пута Рашка – Нови Пазар у РепублициСрбији. Применом модела на пропустима експерименталне путне деоницеутврђено је да је запуњеност путних пропуста каменим наносом основни узрочниквисоких вредности ризика. У оквиру новог модела процене ризика извршена јеанализа утицаја примене радова на санацији и реконструкцији путних пропуста уциљу смањења вредности ризика. Резултати свих спроведених анализа сууобличени у форму техничког извештаја о процени ризика од анализиране појаве,и представљају излаз модела. Добијени резултати су дискотовани у односу нарезултате сличних истраживања у свету на основу чега су извучени закључци идати даљи правци истраживања у изучаваној области., Sprovedeno istraživanje rešava problem određivanja rizika od pojave prelivanjavode preko saobraćajnice u profilu putnog propusta na bujičnom slivu primenomprobabilističkog modela procene rizika i hidrološko-hidrauličkog modelaanalizirane pojave. Formiranje novog hidrološko-hidrauličkog modela procenerizika, koji ukljujučuje više novih pristupa modelovanju različitih procesakoji dovode do analizirane pojave, predstavlja jedan od doprinosa sprovedenogistraživanja. Novoformirani model procene rizika je primenjen na 67 betonskihpropusta na eksperimentalnoj deonici puta Raška – Novi Pazar u RepubliciSrbiji. Primenom modela na propustima eksperimentalne putne deoniceutvrđeno je da je zapunjenost putnih propusta kamenim nanosom osnovni uzročnikvisokih vrednosti rizika. U okviru novog modela procene rizika izvršena jeanaliza uticaja primene radova na sanaciji i rekonstrukciji putnih propusta ucilju smanjenja vrednosti rizika. Rezultati svih sprovedenih analiza suuobličeni u formu tehničkog izveštaja o proceni rizika od analizirane pojave,i predstavljaju izlaz modela. Dobijeni rezultati su diskotovani u odnosu narezultate sličnih istraživanja u svetu na osnovu čega su izvučeni zaključci idati dalji pravci istraživanja u izučavanoj oblasti., The conducted research solves the risk calculation problem of water overtopping theroad in the culvert cross-section on the ephemeral stream by applying the probabilisticrisk assessment model and the hydrological-hydraulic model of the analyzedphenomenon. The new hydrological-hydraulic model of risk assessment, whichincludes several new process-modeling approaches to the analyzed phenomenon,represents one of the contributions of the research. The new risk assessment model hasbeen applied to the 67 concrete road culverts at the experimental road section of theRaška - Novi Pazar road in the Republic of Serbia. By applying the model to theculverts of the experimental road section, it was determined that the stone sedimentfilling of road culverts is the main cause of high-risk values. Within the new riskassessment model, an impact analysis of the rehabilitation and reconstruction worksapplication in order to reduce the risk value has been performed. The results of allconducted analyzes are shaped in the technical report form of the risk assessment ofthe analyzed phenomenon and represent the model output. The obtained results havebeen discussed concerning the results of similar research in the world, based on whichconclusions have been made and further research directions in the studied field havebeen given.&nbsp

Trajnost betona definisana je njegovom otpornošću na dejstvo štetnih agenasa iz okolne sredine koji dovode do različitih vrsta oštećenja (mehanizmi deterioracije). U ovoj tezi, kroz pregled literature, izvršena je analiza postojećih rezultata istraživanja i znanja o glavnim mehanizmima deterioracije koji predstavljaju najveću opasnost za objekte u različitim klimatskim sredinama. Mehanizmi deterioracije mogu uticati na strukturu betona (mraz i soli za odmrzavanje) ili na pojavu korozije armature unutar betona (karbonatizacija i penetracija hlorida). Na deterioracione mehanizme i koroziju koja nastaje njihovim dejstvom u velikoj meri utiče prisustvo prslina. Prsline koje nastaju kao posledica savijanja presecaju armaturu i znatno olakšavaju prodor kiseonika i vode. Shodno tome, uloga prslina prouzrokovanih opterećenjem ne sme se zanemariti u sagledavanju upotrebnog veka armiranobetonskih (AB) konstrukcija. Korozija izazvana hloridima bila je predmet mnogih istraživanja proteklih godina. Za razliku od nje, u literaturi postoji vrlo malo podataka o uticaju prslina na koroziju armature izazvanu karbonatizacijom, pogotovo na razvoj korozije tokom vremena. Došlo se do zaključka da deterioracija AB konstrukcija usled korozije armature izazvane karbonatizacijom predstavlja jedan od glavnih problema trajnosti širom sveta, imajući u vidu da je veliki broj infrastrukturnih objekata izložen okruženju bogatom ugljen–dioksidom (CO2). Zbog toga je karbonatizacija postala važno pitanje u analizi trajnosti AB konstrukcija. Da bi se generisalo novo znanje i doprinelo poboljs anju postojećih standarda i inz enjerske prakse, razvijena je odgovarajuća eksperimentalna postavka kako bi se ispitao uticaj prslina na dubinu karbonatizacije i trajnost AB elemenata napravljenih od različitih vrsta betona... Durability of concrete is defined by its ability to resist harmful environmental agents that damage concrete (deterioration mechanisms). In this thesis an analysis of existing knowledge about most harmful deterioration mechanisms in different climates was made. These mechanisms affect inner concrete structure (freeze/thaw with de-icing salt) or induced reinforcement corrosion (carbonation and chloride penetration). The most important factor that affects concrete deterioration is the appearance of cracks on reinforced concrete (RC) structures. The presence of cracks that cross the reinforcement physically interrupts the passivation layer and induces the beginning of corrosion. Accordingly, the influence of cracks should not be neglected when the service life of RC structures is analysed. Chloride induced corrosion has been the subject of many studies in recent years, but there is a very little information about the influence of cracks on carbonation induced corrosion. Furthermore, deterioration of RC structures due to carbonation induced corrosion is one of the major durability issues worldwide, given that a large number of structures are exposed to a carbon dioxide (CO2) rich environment. Therefore, carbonation has become an important issue in RC structures durability analysis. In order to generate new knowledge and contribute to the improvement of existing standards and engineering practice, an appropriate experimental setup was developed to evaluate the influence of crack widths on the carbonation depth and durability of RC elements made from different concrete types...

During the exploitation period, the properties of reinforced concrete in structures constantly decrease, resulting in damage that directly affects serviceability of the structures. Initiation and development of damage are time-dependent phenomena accompanied by deteriorating processes, which are differently implied depending on the environment. The influence of environment is an important factor that determines type of damage and mode of propagation, and damage level depands on the exposure of structures elementsto aggresive action.

У докторској дисертацији су приказана испитивања мјешавина за хладнерециклаже на лицу мјеста гдје се користи постојећи материјал. Удосадашњим истраживањима највише су коришћени цемент, битуменскаемулзија и пјенушави битумен. У овим истраживањима су коришћеницемент и битуменска емулзија а поред њих и летећи пепео, зеолит, згураи бакелит. Укупно је испитивано 7 мјешавина. Испитивања су урађенапрема Виртген упутству за хладне рециклаже. Испитиване су индиректнезатезне чвртоће и динамички модули еластичности након 7 и 28 дана засуве узорке, након 28 дана за водом засићене узорке и за узоркеизложене дејству мраза., U doktorskoj disertaciji su prikazana ispitivanja mješavina za hladnereciklaže na licu mjesta gdje se koristi postojeći materijal. Udosadašnjim istraživanjima najviše su korišćeni cement, bitumenskaemulzija i pjenušavi bitumen. U ovim istraživanjima su korišćenicement i bitumenska emulzija a pored njih i leteći pepeo, zeolit, zgurai bakelit. Ukupno je ispitivano 7 mješavina. Ispitivanja su urađenaprema Virtgen uputstvu za hladne reciklaže. Ispitivane su indirektnezatezne čvrtoće i dinamički moduli elastičnosti nakon 7 i 28 dana zasuve uzorke, nakon 28 dana za vodom zasićene uzorke i za uzorkeizložene dejstvu mraza., In the doctoral dissertation, tests of mixtures for cold in-place recycling whereexisting material is used are presented. In previous research, cement, bitumenemulsion and foamed bitumen have been used the most. Cement and bitumenemulsion were used in these researches, as well as fly ash, zeolite, slag andbakelite. A total of 7 mixtures were tested. The tests were performedaccording to the Wirtgen cold recycling maunal. Indirect tensile strengths anddynamic modulus of elasticity were tested after 7 and 28 days for watersaturatedspecimens and for specimens exposed to frost.

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.

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.

Doktorska disertacija razrađuje metodologiju izrade modela upravljanja poplavama na velikim ravničarskim rekama korišćenjem preciznih digitalnih modela terena (DTM) i kombinacije 1D/2D hidrauličkih modela nestacionarnog tečenja. Za razradu modela korišćena je reka Dunav na teritoriji Srbije sa svojim pritokama. Dužina hidrauličkog modela je 715 km i postignuta tačnost modela, poređenjem izračunatih i izmerenih nivoa na devet vodomernih stanica, je ispod 10 cm. Dosadašnja strategija odbrane od poplava na velikim rekama, kao što je Dunav, bazirala se na "pasivnim merama" izgradnje nasipa i kejskih zidova. U radu je prikazana mogućnost primene nove strategije upravljanjem poplavnog talasa preko uređenih retenzija. Rezultati disertacije su omogućili i rekonstrukciju poplavnog talasa iz 1965. g., The dissertation elaborates a methodology for flood management model onlarge lowland rivers using precision digital terrain models (DTM) andcombined 1D/2D unsteady flow model. For the development of the model,the river Danube on the territory of Serbia was used with its tributaries. Thelength of the hydraulic model is 715 km and the achieved accuracy of themodel, by comparing the calculated and observed levels on 10 waterstations, is below 10 cm. Оur current defense against floods in big lowlandrivers is relied on passive defence with building and overhanging existinglevees and walls. In dissertation is shown the possibility of applying a newstrategies of flood management with retentions. The results of thedissertation also enabled the reconstruction of the 1965. flood wave.

U disertaciji je razmatran problem nosivosti ankera na čupanje i smicanje u betonu veoma visokih čvrstoća. Izdvojena su tri parametra koji imaju značajan uticaj na nosivost ankera. Realizovano je obimno eksperimentalno istraživanje, koje je koncipirano tako da se dalje može koristiti u numeričkim analizama. Zaključci su izvedeni na osnovu numeričke analize i definisanja uticaja variranih parametara pomoću neuronskih mreža i faktorijalnog eksperimenta. The dissertation discusses the problem of load anchors to pulling out and shearing in ultra high strength concrete. Allocate three parameters that have a significant impact on the load capacity of anchors. Realized an extensive experimental research, which is designed so that could be used in numerical analysis. Conclusions are drawn on the basis of a numerical analysis, and defining the influence of varying the parameters using the neural network and the factorial experiment.

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.

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanjaizvršenog na uzorcima pripremljenim sa različitim učešćem struganog asfalta (RAP)i dodatnog - "novog" drobljenog kamenog agregata. Variranjem učešća struganogasfalta i dodatnog drobljenog kamenog agregata i variranjem učešća oba vezivaomogućeno je praćenje uticaja sastava na mehaničke karakteristike mešavine.Uticaj vrste i količine upotrebljenog veziva na mehaničke karakteristike nosećegsloja kolovoza sagledano je kroz variranje sadržaja cementa i bitumenske emulzije.Predmet istraživanja je definisanje međusobne zavisnosti odnosno korelacije,određenih mehaničkih karakteristika mešavine u funkciji vrste i količinekomponentnih materijala i veziva i ocena njihovih fundamentalnih mehaničkihkarakteristika., In dissertation are resented results of own experimental research onsamples that have been prepared with different amount of reclaimedasphalt (RAP) and the additional - "new" crushed stone aggregate. Byvarying participation of reclaimed asphalt and additional crushed stoneand varying participation of both binders monitoring of the impact of thecomposition on the mechanical properties of the mixture was enabled.The influence of type and amount of binder on the mechanical propertiesof the pavement base layer is seen through variation in the content ofcement and bitumen emulsion. The subject of the research is to define themutual dependence and correlation of certain mechanical characteristicsof the mixture as a function of the types and quantities of componentmaterials and binders and evaluation of their fundamental mechanicalproperties.

The interest of the professional public in the field of civil engineering for usage of self-compacting concrete and potentials of implementation of recycled aggregate in making of this type of concrete is on the rise, primarily because of the dwindling reserves of natural raw materials, and because of the increasing amounts of construction rubble and waste. The experimental-theoretical analysis implemented in this dissertation was used to monitor and analyze behaviour of reinforced concrete continuous beams made of self-compacting concrete made from natural (river) aggregate, as well of continuous beams in which the coarse natural aggregate was replaced in varying proportions, with the quality aggregate made of recycled concrete prefabricates. In addition to defining the ultimate strength state, the ultimate serviceability state was verified, while the stress-strain states of the beams and formation of plastic joints was monitored. Comparative analysis of experimental results was conducted, in which continuous beams with varying share of steel reinforcement made of self-compacting concrete with natural aggregate and the beams made of the self-compacting concrete with quality recycled aggregate were compared. By using the finite element method, continuous beams were modelled, and numerical non-linear analysis was conducted. The continuous beams where coarse natural aggregate was partially replaced by the recycled aggregate are comparable, in structural terms, and competitive with the beams made of self-compacting concrete made with natural aggregate, and they are also justified in terms of environment protection.

Durability of hydraulic engineering structures in most part depends on the resistance of concrete surface to mechanical abrasion. Hydro-abrasion represents a surface damage caused by continuous removal of material due to impact of waterborne hard particles. This form of progressive deterioration of concrete surface occurs, to a varying extent, in almost all hydraulic engineering structures. Therefore, hydro-abrasion wear of concrete in general causes reduction of the service life of a hydraulic engineering structure, as well as an increase in operating costs due to the necessary maintenance, and the downtime of the structure during the repair period. In general, little is known about the onset of concrete hydro-abrasion and about development of this damage in time. Presently, there is no standard testing method for hydro-abrasive resistance of concrete in laboratory conditions, which can to a great extent simulate the natural abrasion conditions. Also, the factors representing the physical, mechanical and structural concrete characteristics, and which affect its resistance to wear have not been sufficiently investigated. In the literature is discussed mostly the hydroabrasive resistance of high-strength concretes made with natural crushed or river aggregate, which are reinforced by addition of the silica powder or micro-reinforcement, with a high quantity of cement (higher than 400 kg/m3). The potential for application of recycled materials and reduced quantity of cement for production of the concretes resistant to hydroabrasion is presented in a limited scope. The paper investigates and analyzes the potential for production of cement concrete in which the cement content has been partially replaced by fly ash or silica powder, and where fine river aggregate has been partially replaced by recycled granulated rubbers, with the addition of micro-fiber (steel or polypropylene), with the aim to increase resistance to hydro-abrasive action. Performances of these concretes in fresh and hardened state were compared with the performances of reference concrete without the partial replacement of cement and fine aggregate and without micro-fibers. The tests of hydro-abrasive resistance of concrete was performed on the original apparatus constructed in the Laboratory of building materials at the Faculty of Civil Engineering and Architecture of Niš, which facilitates that the jet of water and sand mixture impacts the concrete tests slab at a high speed. The parametric analysis of the effects of individual mechanical characteristics on the hydro-abrasive resistance of concrete was done. For the purposes of the research, a total of eighteen types of concrete was made, which can be divided into three groups of six mixtures. The first group consists of the concrete mixes where no partial substation of cement was performed, the second group consists of the concrete mixtures where cement was substituted by filter ash, in the amount of 20% in respect to the cement mass, while the third group consists of the concrete mixes where the cement was substituted with the silica powder in the amount of 10% in respect to the cement mass. Within each group, there is a mixture where a part of fine river aggregate was replaced by the granulated recycled rubber in the amount of 10% in respect to the aggregate volume, followed by two concrete mixtures where polypropylene fibers have been added (monofilament to one and fibrillated to the other mixture), then two mixtures where hooked end steel fibers were (in one those are fibers 30 mm long and in the other those are fibers 50 mm long) and finally, there is the concrete mix without partial replacement of the fine river aggregate with recycled rubber and without the addition of fibers. The conclusions are formulated based on the processed and systematized results of the experimental research, and the performed parametric analysis of the effects of individual mechanical characteristics on the hydro-abrasive resistance of concrete. In general, the most intensive effect regarding increase of hydro-abrasive resistance of concrete is achieved by the partial replacement of the fine river aggregate by the recycled granulated rubber. Also, concrete reinforcement with polypropylene fibers contributes to the considerable increase of hydro-abrasive resistance of concrete, whereby the better effect is achieved using the fibrillated fibers. The addition of steel fibers in concrete does not result in a considerable increase of the hydro-abrasion resistance. The concretes made with the partial replacement of cement by fly ash have lower hydro-abrasive resistance in comparison to the reference concrete, while with the addition of polypropylene fibers, their resistance becomes approximately equal to the resistance of the reference concrete. Partial replacement of cement with silica powder contributes to the increase of hydro-abrasive resistance of concrete. The parameters such as compressive strength, flexural strength, splitting tensile strength, tensile strength determined using „Pull-off“ method, static modulus of elasticity and resistance to abrasion wear can be the factors for prediction of hydro-abrasive resistance of concrete, due to the existence of strong. The behavior of concrete exposed to hydroabrasive action cannot be fully predicted based on the „Drop weight“ tests of the impact resistance of concrete. The accelerate abrasion test method implemented in the research is suitable for analysis of hydro-abrasive resistance of concrete.

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.

Over the last twenty years the two contradictory processes, connected to the durability of concrete structures, were observed: improvement of the quality of concrete mixtures, as a result of a continious growth of the knowledge in technology and of the improvement of codes and standards, led toward the potential durability of concrete structures, and a general decline of the quality of performance of the works, because of gradual reduction in the number of well skilled workers in concreting, affecting a decrease of actual durability of concrete structures. The exceed of the gap between these two mutual opposed processes can only result through a decisive increase of the industrialisation level of the construction process of works, i.e. through the elimination of the effect of „man – factor“ on the quality of performed structures. By use of Self–Compacting Concrete it is possible to achieve this aim. The durability of structures then exclusively depends on the achieved quality of concrete mixture. Developed during last decade of 20th century in Japan and continental Europe, today, Self-Compacting Concrete is applied in USA and United Kingdom as much as in the Middle East. By it’s nature, Self-Compacting Concrete does not need compaction by vibration. Compaction of this concrete, in every part, or in every corner of the formwork, including it’s hardly available parts, is done without any external forces except it’s own weight. These properties are achieved by adding superplasticizers, commonly with new Viscosity Modification Admixtures, or/and determened amount of powders. It is possible to use different mineral additions, where the use of those who are industrial by - product (like fly ash) has multiple environmental benefits. Concept of sustainable development, which beside sociological and economic aspects, include saving of energy, environment protection and preservation of an restorable natural resources, presents strategic determination of various economic sectors. In that way great contribution is expected from construction industry. Lack of natural aggregate in urban areas and increasing distance between deposits of high – quality natural aggregate and building sites, forced building contractors to analyze possibility of change of natural aggregate with recycled materials (masonry, slag, concrete, etc.). On the other hand, huge amount of old concrete exists in urban areas and it’s removal and deposition is a big ecological problem. Aim of this paper is analysis of properties and technology of Self-Compacting Concrete with different mineral additions (lime, fly ash and silica fume), natural and recycled aggregate, considering mixes without recycled aggregate, with third recycled fraction, and with second and third recycled fractions.

U disertaciji je predložen opšti model za upravljanje uticajima na životnu sredinu u okviru proizvodnih procesa proizvodnje podnih obloga, zasnovan na metodi ocenjivanja životnog ciklusa proizvoda i procesa. Model je sistematično predstavljen kroz opis osnovnih delova - modela inventara životnog ciklusa i modela za ocenjivanje uticaja životnog ciklusa. Disertacija sadrži i detaljan opis podloga na kojima je model razvijen. Verifikacija razvijenog modela je sprovedena kroz tri studije slučaja., The dissertation proposes a general model for managing environmental impacts within the manufacturing process of flooring coverings, based on the method of life cycle assessment of products and processes. The model is systematically present by describing the main parts - the life cycle inventory model and a model for the life cycle impact assessment. Dissertation contains a detailed description of the background bases on which the model is developed. Verification of the model is carried out through three case studies.

Recikliranje betonskog otpada je jedno od održivih rešenja za rastuće probleme sa deponijama građevinskog otpada i nekontrolisano iskorišćavanje prirodnih resursa. Rezultat procesa je agregat od recikliranog betona koji se trenutno dominantno koristi za podloge puteva i nekonstruktivne betonske elemente. Sa stanovišta zaštite resursa, smanjenja energije i razvoja ekološke svesti, važno je istražiti da li se beton na bazi recikliranog agregata može koristiti za elemente armiranobetonskih konstrukcija. Predmet istraživanja u ovoj disertaciji su elementi konstrukcije, tačnije gredni nosači napravljeni od betona na bazi recikliranog agregata (RAC) i njihovo ponašanje pod dejstvom kratkotrajnog opterećenja do loma savijanjem ili smicanjem. Formirana je baza podataka i obavljena statistička analiza o mehaničkim svojstvima RAC betona u odnosu na uporedne betone sa prirodnim agregatom (NAC). Eksperimentalni rad obuhvatio je ispitivanje recikliranog agregata, betona na bazi recikliranog agregata i grednih nosača napravljenih od takvog betona. Rezultati ispitivanja svojstava agregata i probna ispitivanja fizičko-mehaničkih svojstava serija RAC i NAC betona poslužili su kao ulazni parametar za projektovanje sastava 3 betonske mešavine sa 0%, 50% i 100% recikliranog agregata krupne frakcije, iste projektovane čvrstoće pri pritisku. Ukupno je do loma ispitano 18 greda, statičkog sistema prosta greda, raspona 3.0 m. Od toga, napravljene su 3 serije od po 3 grede sa različitom količinom podužne armature (0.28%, 1.46% i 2.54%). Koncept ispitivanja postavljen je tako da se faznim povećanjem opterećenja dođe do loma nosača usled savijanja u sredini raspona. Takođe, napravljene su 3 serije od po 3 grede od betona sa 0%, 50% i 100% krupnog RAC i sa različitom količinom poprečne armature (0%, 0.14% i 0.19%), predviđenih za ispitivanje smičuće nosivosti. Izvršeno je poređenje zavisnosti sila-pomeranje, slika prslina, ugiba, dilatacija u betonu i armaturi, oblika loma i graničnih nosivosti greda od klasičnog i RAC betona, bazirano na sopstvenim i drugim rezultatima ispitivanja. Testirana je mogućnost primene savremenih propisa koji se odnose na NAC betone na gredne RAC elemente, kroz poređenje analitičkih predikcija i eksperimentalnih vrednosti momenta savijanja pri pojavi prve prsline, ugiba, graničnih momenata savijanja i granične smičuće sile. Takođe, izvršeno je poređenje sopstvenih i drugih rezultata eksperimentalnih ispitivanja osnovnih parametara nosivosti greda koje su dominantno izložene savijanju ili smicanju... Recycling of waste concrete is one of the sustainable solutions for the growing waste disposal crisis and depletion of natural aggregate sources. As a result, recycled concrete aggregate (RCA) is produced, and so far it has mostly been used in low-value applications such as for the pavement base. But, from the standpoint of promoting resource and energy savings and environmental preservation, it is essential to study whether a concrete made of recycled aggregates - recycled aggregate concrete (RAC) can be effectively used as a structural material. Structural reinforced concrete elements were in the focus of this investigation, i.e. beam girders made of RAC and their behaviour up to flexural and shear failure under short-time loading. A very wide data base was formed and statistic analysis of relations between mechanical properties of RAC and corresponding natural aggregate concrete (NAC) was performed. The experimental research consisted of investigations of recycled concrete aggregate, recycled aggregate concrete and structural behaviour of beams made of RAC. Test results of RCA investigation and trial investigations of physical and mechanical properties of RAC were used as basic parameters for the design of 3 concrete mixtures with 0%, 50% i 100% of coarse RCA with the same compressive strength. Full-scale tests were performed on 18 simply supported beams with span of 3.0 m until the failure load due to flexure or shear was reached. Firstly, three series of beams made of three types of concrete and different ratio of flexural reinforcement (0.28%, 1.46% and 2.54%) were formed. Experiment on beams was performed by increasing the load level until flexural failure in the middle of span occurred. Furthermore, three series of beams with different ratio of shear reinforcement (0%, 0.14% i 0.19%) and concrete with 0%, 50% and 100% of coarse RCA were prepared to examine shear behavior. Comparison of load-deflection behavior, crack patterns, service deflections, strains in concrete and reinforcement, failure modes and ultimate flexural and shear capacity of NAC and RAC beams was made. The possibility of using equations from NAC codes to RAC beams was tested by comparison of an analytical expressions and experimental results related to cracking moments, deflections, ultimate bending moments and ultimate shear capacity. The analysis of own and other authors’ test results was performed both on flexural and shear behavior of RAC reinforced concrete beams...