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Diplomski rad prvotno prolazi kroz teorijsku podlogu koja se sastoji od četiri poglavlja. U prvom poglavlju govori se općenito o pukotinama i njihovom djelovanju na beton. U drugom poglavlju govori se o djelovanju bakterija na zacjeljivanje betona s obzirom na njihov način ugradnje što podrazumijeva direktnu primjenu i inkapsulaciju. U trećem poglavlju govori se o kapsulama, načinu njihove ugradnje i o materijalu od kojeg su napravljene. U posljednjem teoretskom poglavlju govori se o kristalnim dodacima u betonu, njihovim mehanizmima djelovanja, njihovom djelovanju u različitim uvjetima okruženja, te sinergijskim odnosima s portlandskim vapnenačkim cementom i superupijajućim polimerima. U eksperimentalnom dijelu rada izrađene su tri mješavine, referentna, mješavina s aerantom koji se oopćenito koristi za poboljšanje svojstava prilikom smrzavanja i odmrzavanja i mješavina s 1 % kristalnog hidrofilnog dodatka. Ispitana su svojstva betona u svježem i očvrslom stanju. Zaključeno je da kristalni hidrofilni dodatak može poboljšati otpornost betona uslijed ciklusa smrzavanja i odmrzavanja u kontekstu smanjenja unutarnjih oštećenja., The paper initially goes through the theoretical basis, which consists of four chapters. In the first chapter, cracks and their effect on concrete are discussed in general. The second chapter talks about the effect of bacteria on concrete healing with regard to their method of installation, which implies direct application and encapsulation. The third chapter talks about capsules, the way they are installed and the material they are made of. The last theoretical chapter discusses crystalline additives in concrete, their mechanisms of action, their action in different environmental conditions, and synergistic relationships with Portland limestone cement and superabsorbent polymers. In the experimental part of the work, three mixtures were prepared; a referent mixture, a mixture with an air entraining agent which is generally used to improve properties during freezing and thawing, and a mixture with 1 % crystalline hydrophilic additive. The properties of concrete in fresh and hardened state were tested. It was concluded that the crystalline hydrophilic admixture can improve the resistance of concrete due to freezing and thawing cycles in the context of reducing internal damage.

Kako bi se zadovoljio jedan od temeljnih zahtjeva koji se postavlja na materijale, potrebno je istražiti kako povećati njihovu otpornost na cikluse smrzavanja i odmrzavanja, koji su jedan od glavnih uzroka degradacije betona. Ponavljanje ovih ciklusa rezultira oštećenjem materijala, koje se javlja ili u obliku površinskog ljuštenja ili u obliku unutarnjeg raspucavanja. Zamiješane su referentna mješavina betona, mješavina s dodatkom aeranta te mješavina betona s dodatkom za samocijeljenje na bazi kristalizacije. Očvrsli uzorci betona izloženi su ciklusima smrzavanja i odmrzavanja prema normi HRS CEN/TS 12390-9:2016. Rezultati ispitivanja otpornosti betona na cikluse smrzavanja i odmrzavanja pokazuju da mješavina betona s kristalnim hidrofilnim dodatkom može smanjiti unutarnja oštećenja uslijed ciklusa smrzavanja i odmrzavanja.

V diplomski nalogi smo na osnovi eksperimentalnih analiz določili mrazoobstojnost betona z dodatkom elektrofiltrskega pepela in reciklirane gume. Kot nadomestek dela veziva smo uporabili dva tipa pepela, kot nadomestek dela agregata pa reciklirano gumo iz SR, EMPD in EPM. Vsem vzorcem je bil za izboljšanje mrazoobstojnosti dodan aerant. Polovico vzorcev smo izpostavili zmrzovanju in tajanju, njihove mehansko-fizikalne lastnosti smo primerjali z nezmrzovanimi vzorci. Na vseh vzorcih smo izvedli preizkuse tlačne trdnosti, s pomočjo ultrazvoka pa smo jim izmerili še modul elastičnosti. Na podlagi rezultatov lahko zaključimo, da samo zmrzovanje in tajanje na tlačno trdnost in modul elastičnosti ni vplivalo toliko, kot je na te lastnosti vplivala izbira elektrofiltrskega pepela. Rezultati so pokazali, da so tudi delci reciklirane gume dobro vplivali predvsem na mrazoobstojnost betona, saj so delci povečali mesta, kjer se lahko med zmrzovanjem širi led, ki je nastal med zmrzovanjem. In this thesis, on the basis of experimental analyzes, the freeze/thaw resistance of concrete was determined by the addition of fly ash and recycled rubber. As a substitute for the Portland cement, two types of ash were used, and the recycled rubber was used as a substitute for the mineral aggregate. An air entainer was added to all the samples to improve the freeze/thaw resistance. Half of the samples were exposed to frost, so we could compare each other how freezing and thawing affects the properties of the samples themselves. All samples were tested for compressive strength, and with the help of ultrasound we also measured the elastic modulus. Based on the results we concluded that the freezing and thawing did not affect the compressive strength and modulus of elasticity as much as these features were affected by the choice of fly ash.

V diplomski nalogi smo opravili eksperimentalno analizo cementne paste z dodatkom elektrofilterskega pepela (EFP), reciklirane gume in aeranta. Na vzorcih hidratizirane cementne paste smo z Dugganovim testom izzvali zakasnelo tvorbo etringita (DEF). Posledice te reakcije so bile deformacije, katere so bile kompenzirane z zelo majhnimi delci reciklirane gume. Majhni delci reciklirane gume so delovali kot majhne vzmeti v togi cementni matrici. Posledično je prišlo do zmanjšanja deformacij v cementnem kamnu. In this thesis, we conducted an experimenatl analysis of the cement paste containing fly ash (EFA), recycled rubber and air-etraining agent. On samples of the hydrated cement paste with Duggan's test we provoked delayed ettringit formation (DEF). The cosquences of these reactions were deformation , which they were compensated with very small particles recycled rubber. Small particles recycled rubber are acted as small springs in a rigid cement matrix. Consequently, there has been a reduction in deformation in cement stone.

Rad obuhvaća skup postojećih znanja o svojstvima, tehnologiji i projektiranju sastava valjanog betona za građenje prometnica. U eksperimentalnom dijelu rada napravljene su mješavine valjanog betona koje se razlikuju prema količini veziva, vodovezivnom omjeru, maksimalnom zrnu agregata i dodatku aeranta. Na temelju dobivenih rezultata analiziran je utjecaj pojedinih parametara sastava, a posebno dodatak aeranta, na svojstva valjanog betona.

V diplomski nalogi smo opravili eksperimentalno analizo betonske mešanice z dodatkom elektrofiltrskega pepela (EFP), reciklirane gume in aeranta. Mehurčki od aeranta v hidratiziranem betonu so služili kot nukleacijska mesta za rast kristalov etringita. Na vzorcih hidratiziranega betona smo z Dugganovim testom izzvali zakasnelo tvorbo etringita (DEF), ki običajno povzroči degradacijo betona. Napetosti, ki so posledica volumskih sprememb zaradi DEF, so bile kompenzirane z delci reciklirane gume, ki so delovali kot vzmeti v togi cementni matrici. Posledično ni prišlo do nobenih poškodb na preizkusnih vzorcih iz eksperimentalne betonske mešanice. In this thesis, we conducted an experimental analysis of the concrete mixture containing fly ash (EFA), recycled rubber and air entraining agent. The bubbles of an air entraining agent in the hydrated concrete were served as a nucleation sites for growth of crystal ettringit. On the samples of the hydrated concrete with Duggan's test we provoked delayed ettringit formation (DEF), which usually results in degradation of the concrete. Stresses, caused by volume changes due to DEF, have been compensated by the particles of recycled rubber, which acted as a spring in a rigid cement matrix. Consequently, there has been no damage to the test specimens from the experimental concrete mix.

V diplomskem delu z naslovom »Uporaba betonske mešanice z dodatkom reciklirane gume in elektrofiltrskega pepela« je predstavljena uporaba betonov, pri katerih smo del veziva nadomestili z elektrofiltrskim pepelom, del agregata pa smo nadomestili z reciklirano gumo. Izvajali smo preizkuse tlačnih trdnosti betona in preizkuse mrazoobstojnosti. V seriji vzorcev smo uporabili aerant in med seboj primerjali dobljene rezultate vzorcev brez aeranta in vzorce z dodatkom aeranta. Uporaba elektrofiltrskega pepela in reciklirane gume v betonski mešanici je predstavljena kot možnost ponovne uporabe odpadnih materialov. In thesis entitled »Use of concrete mixtures with recycled rubber particles and fly ash additions« is presented using of cocnrete, which was the part of binder replaced by fly ash, part of the aggregate was replaced by recycled rubber. We made tests of compressive strenght and freez/thaw resistance. In a series of samples we used the air entraining and compared results obtainined without air entraining samples and samples with the air entraining additons. The use of flyash and recycled rubber in the concrete mixtures is presented as a possible re-use of waste materials.

V diplomskem delu je predstavljena uporaba reciklirane gume pri proizvodnji betonov, ki so prav tako mrazoobstojni. Pri betonski mešanici smo kot nadomestek cementa uporabili elektrofiltrski pepel. V seriji vzorcev je bil uporabljen tudi aerant. Izvajali smo preizkuse tlačnih trdnosti betona, ter med seboj primerjali betonske vzorce brez dodatka aeranta in vzorce z dodatkom aeranta. Iste primerjave smo opravili tudi pri preizkusih mrazoobstojnosti otrdelih betonskih vzorcev. Uporaba reciklirane gume in elektrofiltrskega pepela je predstavljena tudi z vidika ponovne uporabe odpadnih meterialov. The thesis presents the use of recycled rubber in the manufacture of concrete, which are also freeze/thaw resistant. In concrete mixture fly ash was used as a substitute for cement . Air entraining admixture was also used in a series of samples. We carried out tests of compressive strength of concrete, and compared the concrete samples without addition of air entraining and samples with addition of air entraining admixture. The same comparisons was also carried out in tests of freeze/thaw on hardened concrete samples. The use of recycled rubber and fly ash is also presented in terms of re-used waste materials.

V doktorski disertaciji je obravnavan vpliv dodatkov betonu – mikrosilike, superplastifikatorja in aeranta – na povečanje trdnosti vpetja med cementno malto in pletenico kontinuiranih ogljikovih vlaken. Za preiskavo lastnosti vpetja med pletenico ogljikovih vlaken in različnimi cementnimi maltami so bili uporabljeni rezultati izvlečnih preizkusov, ki smo jih primerjali z rezultati analize mikrostrukture mejnih površin. Eksperimentalni rezultati so potrdili, da je uporaba vseh uporabljenih dodatkov betonu izboljšala kvaliteto vpetja. Najbolj je kvaliteto vpetja med pletenico ogljikovih vlaken in eksperimentalno cementno malto povečala uporaba aeranta. Na podlagi analize rezultatov je bilo ugotovljeno, da lahko zračni mehurčki, ki so posledica delovanja aeranta in so locirani v neposredni bližini zunanjih filamentov pletenice, predstavljajo mehansko oviro, zaradi katere se pri izvleku vlaken občutno poveča trenje na mejni površini. Posledično se povečajo trdnost, togost in žilavost vpetja pletenice ogljikovih vlaken v aerirani malti. V nadaljevanju je v disertaciji prikazana tudi aplikacija novega načina vpetja pletenice ogljikovih vlaken v betonski konstrukciji v primerjavi s klasično rebrasto jekleno armaturo. Po izvedenih upogibnih preizkusih se je izkazalo, da ima vlaknasta armatura številne prednosti pred konvencionalnimi armaturnimi materiali: bistveno stanjšanje prereza (celo do pet krat), majhno maso, možnost poljubnega oblikovanja konstrukcijskih elementov zaradi fleksibilnosti vlaken ter povečano duktilnost in žilavost kompozita. This paper deals with the influence of admixtures – silica fume, superplasticizer and air entraining agent – on the improvement of the bond strength between bundled carbon filaments and cement mortars. Pull-out tests were carried out to examine the bond between carbon-fibre yarn and various cement matrices. An overall microstructural analysis was conducted and correlated with pull-out data. Experimental results showed that all the applied admixtures contributed to improved bonding. The air entraining agent was found to be the most effective in improving the bond strength of the studied carbon-fibre reinforced cement mortar. Air bubbles formed inside the mortar mix as a result of added air entraining agent and the ones formed in the vicinity of the outer filaments of the yarn may provide a mechanical barrier at the interface, leading to a significant increase in interface friction. Additionaly we showed the possibility of using fibrous reinforcement of thin sections compared to a conventional reinforcement with a steel rebars. After carried out bending tests it was proved that the fibrous reinforcement had several advantages over conventional reinforcement materials. The advantages of fiber-reinforced concrete composites are primarily essential thiness of the section (up to five time), low mass, the possibility to arbitrary create elements because of the fiber flexibility and increased ductility and toughness.

U eksperimentalnom dijelu rada provedena su ispitivanja otpornosti betona na cikluse smrzavanja i odmrzavanja sa različitim agresivnim tvarima (natrij klorid, urea, kalcij klorid). Ove vrste agresivnih tvari su odabrane jer se iste najviše koriste za odleđivanje na različitim prometnim površinama (ceste, autoceste, aerodromi). Betoni su se razlikovali prema vodovezivnom omjeru i dodatku aeranta.

V diplomskem delu je predstavljen vpliv induciranih tlačnih napetosti v cementni matrici na jakost vpetja vlaken, na prenos obremenitve iz matrice na vlakna in na mehanske lastnosti vlaknastega cementnega kompozita med obremenitvijo. Tlačno napetost zaradi krčenja betona smo izmerili s posebej za ta namen razvitim merilcem. Študije smo opravili na vzorcih s cementno malto, v katero smo dodali dodatek aeranta. Med procesom mešanja malte so se kot posledica delovanja aeranta v matrici formirali zračni mehurčki, ki so zaradi povečane poroznosti povzročili precejšnje krčenje cementne matrice in s tem pritiske pravokotno na vlakna. S tem se je povečalo tudi trenje na mejni površini. S pomočjo izvlečnih testov smo na eksperimentalnih preizkušancih v časovnih intervalih izmerili izvlečno silo in opisali vpliv zaradi krčenja povzročenih bočnih pritiskov. Tendenca izmerjenih rezultatov notranjih deformacij se giblje v skladu z navedbami literature. The purpose of present diploma thesis was to describe the impact of induced normal stresses inside the cement matrix on interfacial bond strength, load transfer between fibres and matrix and mechanical properties of fibrous cement composites during loading. Internal compressive stresses due to shrinkage of concrete were measured with the measuring device developed for this purpose. Studies were performed on samples of cement mortar with addition of an air entraining agent. Air bubbles formed inside the mortar mix as a result of added air entraining agent increased porosity and caused substantial shrinkage of cement matrix and subsequent pressure perpendicular to the fibers. This also increased the interfacial friction. Composite bond characteristics were evaluated with conventional pull-out tests. The results of the fibre pull-out tests were then combined with measured and calculated values of shrinkage induced lateral pressure. The results of measurements performed in this study are in accordance with findings of the literature.

V okviru diplomske naloge je bil razvit in izdelan merilec za merjenje volumenskih deformacij v cementni malti. Merilec je omogočal začetek merjenja takoj po vgraditvi v togi brezšivni jekleni kalup valjaste oblike, torej je bilo omogočeno spremljanje razvoja deformacij, ki se razvijejo v prvih urah po zamešanju cementne malte. Meritve so bile opravljene na čisti cementni malti in na malti, kateri je bila dodana kontrolirana količina aeranta. Aerant je bil uporabljen kot sredstvo za nastanek ciljne mikrostrukture cementne malte. Potrjena je bila hipoteza, da stabilizirani zračni mehurčki nudijo neomejen prostor za neovirano in intenzivno rast kristalov CH in etringita na obodu mehurčka in povzročijo volumensko ekspanzijo cementne matrice v začetni fazi hidratacije, ki je bistveno večja, kot pa je ekspanzija malte brez aeranta. V kasnejši fazi hidratacije pa zračni mehurčki vplivajo na intenzivnejše krčenje. Tendenca izmerjenih rezultatov notranjih deformacij, tako ekspanzije kot tudi krčenja, se giblje v skladu z navedbami literature. In the presented diploma thesis the device for measurement of volumetric deformations on cementitious mortars was developed and manufactured. The device enabled starting the measurements immediately after casting of fresh mortars into rigid cylindrical steel molds, which gives a possibility of recording the early-age deformations. Two experimental mortar mixes were used: plain cement mortar and the mortar with addition of air entraining agent (AEA). The addition of AEA caused the formation of the microstructure with finely dispersed air bubbles forming an unlimited space for growth of CH crystals and ettringite. The formation of ettringite and CH crystals is considered as a principal cause of early-age expansion much higher on mortars with AEA. Subsequent shrinkage was found to be also more intense on mortars with AEA. The results of measurements performed in this study are in accordance with findings of literature.

Plastoaerant je aditiv koji ima dva glavna efekta, djeluje kao plastifikator i aerant. U radu je ispitan utjecaj plastoaeranta na ranu čvrstoću cementnog morta. Plastoaerant znatno smanjuje početne čvrstoće cementa. Prikladnost aeranta za bilo koju najmenu treba provjeriti probnim mješavinama i to u svježem i očvrslom stanju.

Uradu je istražen utjecaj aeranta na hidrataciju cementa praćenjem mehaničkih i fizikalnih karakteristika cementa.

Ispitan je utjecaj sastava mješavina na konzistenciju svježeg betona. Svojstva svježeg betona su mjerena pri šest različitih brzina okretanja lopatice za miješanje, uz mjerenje potrebne snage elektromotora mješalice te normiranim postupkom mjere slijeganja i VEBE postupkom. U mješavinama betona su varirane tri količine cementa (300, 330 i 360 kg), količina aeranta (0 ili 0, 2 % na masu cementa) i količina plastifikatora (0 ili 0, 5 % na masu cementa), količina polipropilenskih, odnosno čeličnih vlakana (0 ili 0, 5 % na volumen betona). Za svaku mješavinu, postepenim dodavanjem vode, varirat će se konzistencija od krute do plastične.