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Rupnikova linija je sistem vojaških utrdb, postavljenih na Rapalski meji, ki naj bi pred drugo svetovno vojno takratno Jugoslavijo varovala pred vdorom Italijanskih sil. Sestavlja jo več kot 4000 armiranobetonskih vojaških objektov, zgrajenih med letoma 1935 in 1940. Delimo jo na (visoko ležečo) zgornjo in (nizko ležečo) spodnjo linijo. Ker bunkerji v svoji življenjski dobi še niso bili sanirani in so nekateri v slabem stanju, smo za izbrane bunkerje na podlagi predhodnih raziskav v okviru magistrske naloge sprojektirali beton, ki naj bi bil primeren za njihovo sanacijo. V okviru raziskave smo preverjali, če so mehanske lastnosti replik betona primerljive z mehanskimi lastnostmi historičnega betona. Vzorce historičnega betona smo izvrtali iz izbranih bunkerjev Rupnikove linije in jih narezali na valje premera 95 mm in višine 100 mm. V raziskavi smo uporabili 9 vzorcev zgornje in 6 vzorcev spodnje linije. Za primerjavo smo v laboratoriju pripravili dve mešanici, repliki historičnega betona. V prvo mešanico, ki naj bi bila namenjena sanaciji izbranih bunkerjev zgornje linije, je bil vgrajen apnenčev agregat, v drugo, ki naj bi bila namenjena sanaciji izbranih bunkerjev spodnje linije, pa smo vgradili dolomitni agregat. Iz vsake mešanice smo pripravili 6 kock dimenzij 100 × 100 × 100 mm in 6 kock dimenzij 150 × 150 × 150 mm, skupaj 24 vzorcev. Vzorcem smo na podlagi meritev s hidravlično stiskalnico najprej določili izhodiščne vrednosti tlačne trdnosti in statičnega modula elastičnosti. Po tem smo vzorce izpostavili 30 ciklom zmrzovanja in tajanja s prisotnostjo talilnih soli. Med ciklanjem smo z ultrazvokom spremljali spremembo tlačne trdnosti in dinamičnega modula elastičnosti, hkrati pa smo jim merili izgubo mase. Na podlagi rezultatov smo se opredelili glede ustreznosti betonskih mešanic za sanacijo z vidika tlačne trdnosti, modula elastičnosti in zmrzlinske odpornosti. Rupnik fortification line is a system of military fortifications on the Rapallo border, built just before the second world war. Its purpose was to defend the Kingdom of Yugoslavia from an attack by Italian forces. The fortification line consists of about 4000 military structures built between 1935 and 1940. Most of the structures were made with reinforced concrete and were split between the upper line (high positions) and the lower line (low positions) made of different concrete mixtures. Some of the structures are in a terrible state and in need of restoration, so we designed a concrete mix suitable for their restoration based on the research included in this thesis. The study compared the mechanical and physical properties of the replicated concrete samples to the samples of historic concrete gained from the structures on the fortification line. Samples of concrete were taken from selected fortifications and shaped into cylinders measuring 95 mm in diameter and 100 mm in height. Of all the samples 9 were taken from the bunkers of the upper line and 6 were taken from those of the lower line. Two different mixtures of concrete were prepared. For the restoration of the upper line, limestone aggregate was used, and for the restoration of bunkers of the lower line, dolomite aggregate was used. Each mixture was used to produce six 100 × 100 × 100 mm cubes and six 150 × 150 × 150 mm cubes, 24 in total. Using a hydraulic press, we set a base value for the concrete specimens' compressive strength and modulus of elasticity. The samples were then exposed to 30 freeze-thaw cycles, with the presence of chlorides, where compressive strength and dynamic modulus of elasticity were measured using ultrasound. Loss of mass was also measured at the same time. The results were used as the basis for determining the suitability of the concrete mixtures for the restoration of the structures on the Rupnik military line.

Vedno bolj pomembno je recikliranje in krožno gospodarstvo ter s tem zmanjšanje pritiska na naravne vire, ustvarjanje trajnostne rasti in zaustavitev izgube biotske raznolikosti. S tem ciljem v mislih, je Evropska Unija sprejela akcijski načrt, katerega del je tudi projekt START CIRCLES. V povezavi s podjetjem M Sora, smo v okviru tega projekta izdelali inovativni hibridni material z imenom »Comet«, ki naj bi se uporabljal v pod okenski odprtini za preprečevanje toplotnega mostu. Za izdelavo smo uporabili odpadne materiale iz proizvodnje lesenih oken – les in steklo ter jih povezali s taninom in poliuretansko matrico. Raziskavo smo zastavili tako, da smo spreminjali le eno spremenljivko naenkrat in opazovali vpliv na fizikalne in mehanske lastnosti izdelanega kompozita. Spreminjali smo deleže PU, tanina, stekla, gostoto, velikost gradnikov in različne deleže določenih velikosti gradnikov. Za vsako izdelano ploščo smo določali lastnosti, ki so najbolj pomembne za ciljno uporabo – gostota, tlačna trdnost (pri 10 % deformaciji), toplotna prevodnost in upogibna trdnost. V vsakem koraku smo določili vzorec z najboljšimi lastnostmi in jo uporabili v nadaljnjih preizkusih. Na tak način smo prišli do končnih vzorcev, ki smo jih nato primerjali z materiali, ki so že na trgu in se v praksi uporabljajo v pod okenski odprtini. Glede na lastnosti, ki smo jih izmerili, smo prišli do zaključka, da je izdelan material primeren za uporabo v pod okenski odprtini. Recycling and the circular economy are becoming increasingly important for reducing the pressure on natural resources, creating sustainable growth and halting the loss of biotic diversity. With this goal in mind, the European Union put in motion an action plan which includes the START CIRCLES project. In connection with the company M Sora, within the framework of this project, an innovative hybrid composite material, called “Comet”, was created. It was meant for use under windows to prevent thermal bridges. Waste materials from window production were used, namely wood and glass, which we bonded with tannin and polyurethane matrix. The research was set in such a way that it was possible to change one variable at a time and observe it's impact on the physical and mechanical properties of the composite. We altered the proportions of PU, tannin, glass and changed the density, wood particle size and the proportions of each size of wood particles. For each manufactured panel, we determined the properties that are the most important for the intended use – density, compressive strength (at 10 % deformation), thermal conductivity and flexural strength. In each step we determined the sample with the best properties and used that for further testing. Using such a procedure, we arrived at the final samples, which we then compared with materials that are already on the market and are being used in practice. Based on the properties we measured, we came to the conclusion that the manufactured material is suitable for use under windows.

RILEM TC 267 TRM– “Tests for Reactivity of Supplementary Cementitious Materials” recommends the Rapid Reliable Relevant (R3) test as a method for determining the chemical reactivity of supplementary cementitious materials (SCMs) in Portland cement blends. In this paper, the R3 test was applied to 52 materials from a wide range of conventional and alternative SCMs with the aim to validate such test. An excellent correlation was found between the cumulative heat release and the bound water determined following the R3 test method. Comparison of the R3 test results to mortar compressive strength development showed that all conventional SCMs (e.g. blast furnace slag and fly ashes) followed the same trend, with the notable exception of very reactive calcined kaolinitic clays. It is discussed, through an in-depth statistical regression analysis of the R3 reactivity test results and the 28 days relative compressive strengths, how reactivity threshold values for classification of the chemical reactivity of SCMs could be proposed based on the R3 test results. Article no.: 142. Opis vira z dne 31. 5. 2022. Abstract. Bibliografija: str. 15-16.

V diplomski nalogi so obravnavane lastnosti betonskih mešanic, katerih vezivo predstavlja žlindrin cement CEM III/B 32,5 N-LH/SR, z nizko toploto hidratacije. Za pridobitev podatkov o lastnostih različnih mešanic so bile opravljene laboratorijske preiskave svežega in strjenega betona. Na svežih mešanicah so bile opravljene preiskave za določitev konsistence (metoda s posedom in metoda z razlezom), na strjenih vzorcih pa so bili določeni tlačna trdnost s porušno metodo in elastični parametri z uporabo ultrazvočne preiskave. Enake preiskave so bile opravljene tudi na betonih s Portlandskim cementom CEM II/B-M (LL-V) 42,5 N. Cementi CEM II/B so najpogosteje uporabljena vrsta cementa v slovenski gradbeniški praksi. Sledila je analiza rezultatov in njihova medsebojna primerjava. Rezultati so pokazali, da so betoni z žlindrinim cementom bolj tekoče konsistence, kot betoni s Portlandskim cementom. Zgodnje vrednosti mehanskih lastnosti, kot so tlačna trdnost ter dinamični modul elastičnosti in strižni modul, so občutno nižje pri betonih z žlindrinim cementom, zaradi počasnejšega oblikovanja produktov hidratacije. Po osemindvajsetih dneh hidratacije pa se razlika tlačnih trdnosti in elastičnih parametrov med betoni z žlindrinim cementom in betoni s Portlandskim cementom bistveno zmanjša. V nekaterih primerih betoni z žlindrinim cementom dosežejo celo višje 28-dnevne vrednosti mehanskih lastnosti. he graduation thesis deals with the properties of concrete mixtures prepared with slag cement CEM III / B 32.5 N-LH / SR with low heat of hydration. Laboratory tests of fresh and hardened concrete were performed to obtain data on the properties of different mixtures. Slump test and flow table test were performed to determine the consistency of fresh concrete. Compressive strength was determined on hardened samples and elastic parameters were measured using the ultrasonic technique. The same tests were performed on concretes with Portland cement CEM II / B-M (LL-V) 42.5 N. CEM II / B types of cement are the most commonly used cements in Slovenian construction practice. After completed laboratory tests, an analysis of the test results and their comparison followed. The obtained results showed that slag cement concretes have a more liquid consistency than Portland cement concretes. Due to the slower formation of hydration products, early age mechanical properties, such as compressive strength and dynamic modulus of elasticity and shear modulus, are significantly lower in the slag cement concretes. After twenty-eight days of binder hydration, the difference in compressive strength and elastic parameters between the slag cement concrete and Portland cement concrete decreases significantly. In some cases, slag cement concrete achieves even higher mechanical properties after twenty eight days.

Namen raziskave je bil preučiti vsebnost celokupnih fenolov ter organskega ogljika v izpirkih treh različnih lesov: domači kostanj (Castanea sativa Mill.), navadna bukev (Fagus sylvatica L.), navadna smreka (Picea abies L.) in navadna smreka zaščitena z baker-etanolaminskim pripravkom Silvanolin%. Prav tako nas je zanimala sprememba tlačne trdnosti vzorcev. Ti so bili izpostavljeni 3. razredu izpostavitve v obdobjih med 4 in 30 mesecev. Topni organski ogljik v izpirkih smo določili s TOC analizo, delež celokupnih fenolov pa z UV-VIS spektrofotometrijo. Meritve tlačne trdnosti smo opravili s strojem Zwick-Roell na zračno suhih vzorcih. Ugotovili smo, da se ob daljšem času izpostavitve delež ekstraktivov poveča, kar se odraža v večjem deležu topnega organskega ogljika in/ali celokupnih fenolov. Razlog za povečan delež ekstraktivov je predvsem biotska razgradnja lesa. Pri določanju tlačne trdnosti smo pri vseh lesnih vrstah ugotovili, da je ta obratno sorazmerna s časom izpostavitve vremenskim vplivom. The purpose of this thesis was to examine the total content of phenols and total organic carbon in the eluate of three different wood species: sweet chestnut (Castanea sativa Mill.), European beech (Fagus sylvatica L.), Norway spruce (Picea abies L.) and Norway spruce protected by a copper-ethanolamine preservative Silvanolin%. The research also explores the change of the compressive strength of the samples. They were exposed to third class exposure in periods between 4 and 30 months. Soluble organic carbon in the eluates was determined by TOC analysis, whereas the proportion of total phenols by UV-VIS spectrophotometry. Furthermore, measurements of compressive strength were performed with the machine Zwick-Roell on air-dried samples. The results show that longer exposure time increases the share of extractives, which is reflected in the greater proportion of soluble organic carbon and / or total phenols. The increased proportion of extractives is mainly caused by bio-degradation of wood. Finally, the study reveals that compressive strength in all wood species is inversely proportional to the time of exposure to weather conditions.

In this paper the possibility of using different regression models to predict the mechanical properties of limestone concrete after exposure to high temperatures, based on the results of non-destructive techniques, that could be easily used in-situ, is discussed. Extensive experimental work was carried out on limestone concrete mixtures, that differed in the water to cement (w/c) ratio, the type of cement and the quantity of superplasticizer added. After standard curing, the specimens were exposed to various high temperature levels, i.e., 200%, 400%, 600% or 800%. Before heating, the reference mechanical properties of the concrete were determined at ambient temperature. After the heating process, the specimens were cooled naturally to ambient temperature and tested using non-destructive techniques. Among the mechanical properties of the specimens after heating, known also as the residual mechanical properties, the residual modulus of elasticity, compressive and flexural strengths were determined. The results show that residual modulus of elasticity, compressive and flexural strengths can be reliably predicted using an artificial neural network approach based on ultrasonic pulse velocity, residual surface strength, some mixture parameters and maximal temperature reached in concrete during heating

V članku predstavimo možnost ocene mehanskih lastnosti betona po izpostavljenosti povišanim temperaturam z uporabo različnih regresijskih modelov in rezultatov neporušnih preiskav. Iz nabora različnih neporušnih preiskav smo uporabili ultrazvočno (UZ) metodo in metodo določanja sklerometričnega indeksa, ki se lahko uporabita neposredno na armiranobetonski (AB) konstrukciji po požaru. S poznavanjem mehanskih lastnosti betona po požaru, določenih z omenjenima metodama, lahko kasneje ocenimo nosilnost preiskane konstrukcije. Rezultati temeljijo na lastni, obsežni eksperimentalni raziskavi, ki je zajemala izdelavo preizkušancev različnih betonskih mešanic. Te so se med seboj razlikovale po vodocementnem (v/c) razmerju, vrsti uporabljenega cementa ter količini dodanega superplastifikatorja. Preizkušanci so bili izpostavljeni različnim povišanim temperaturam, in sicer 200 °C, 400 °C, 600 °C in 800 °C. Po ohladitvi na sobno temperaturo smo na preizkušancih opravili različne neporušne in porušne preiskave. Eksplicitne zveze med rezultati neporušnih in porušnih preiskav, opravljenih na betonskih preizkušancih po izpostavljenosti povišanim temperaturam, smo izboljšali z uporabo umetnih nevronskih mrež. Izkaže se, da na ta način lahko podamo dobro oceno mehanskih lastnosti betona po izpostavljenosti povišanim temperaturam. Hkrati je ta ocena dovolj dobra že v primeru uporabe rezultatov UZ-metode. Oceno pa lahko izboljšamo z dodajanjem informacij o mešanici betona ali najvišji doseženi temperaturi. The paper presents the estimation of predicting mechanical properties of concrete after exposure to elevated temperatures using different regression models and the results from non-destructive test techniques. From a set of different non-destructive techniques, the ultrasonic (US) and rebound number techniques were selected, as portthey can be used directly on a reinforced concrete (RC) structure after exposure to fire. Based on known mechanical properties of concrete after exposure to fire the residual load-bearing capacity of the structure can be estimated. The results are based on extensive experimental study that was carried out on concrete specimens of different concrete mixtures that differed in water to cement (w/c) ratio, the type of used cement, and the amount of added superplasticizer. Next, the specimens were exposed to various high temperatures, i.e. 200 °C, 400 °C, 600 °C, and 800 °C. After the specimens had cooled down to the ambient temperature, non-destructive test techniques were performed, followed by destructive ones. The explicit relationships between the results of non-destructive and destructive test techniques, performed on concrete specimens after exposure to high temperatures, were improved by using artificial neural network (ANN) approach. It was established that by using the ANN approach, good estimation of the mechanical properties of concrete after exposure to high temperatures can be made. At the same time, this estimation is good enough only if the results of the US method are used. However, the estimation can be improved by adding information about the concrete mixture or the maximum temperature reached.

We present design and properties of combined air lime-white cement structural injection grouts containing 17.5% of air lime, 7.5% of cement and 75% of limestone filler, using white Portland cement. Time evolution of the grout setting process during hydration from early to late stages was monitored by NMR spectroscopy and compared to pure cement-paste control samples. The grout setting is significantly slowed down (by more than 10 days). The compressive strengths of the grouts were found in the range 1.5%2.5 MPa, making them efficient materials for the strengthening of historical masonry buildings in Slovenia.

Podjetje M SORA je v bližini Žirov podrlo dotrajan lesen kozolec v Sedejevi dolini v vasi Opale. Iz pridobljenega lesa razvija in izdeluje nova lesena okna. Za namen raziskave smo iz starega lesa kozolca odvzeli okvirno 1 m dolge vzorce tramov, leg in špirovcev. Večina odvzetih vzorcev je bila iz smrekovega lesa, en vzorec pa iz lesa češnje. Iz večjih vzorcev smo pripravili vzorce za testiranje odpornosti proti lesnim glivam po standardu (EN 113) in vzorce za testiranje mehanskih lastnosti. Pri mehanskih testiranjih smo določali upogibno in tlačno trdnost. Določili smo gostoto lesa, izgubo mase, vlažnost vzorcev po izpostavitvi glivam, upogibni elastični modul, tlačno trdnost in upogibno trdnost. Rezultati odpornosti lesna na glive bele in rjave trohnobe so pokazali da je izguba mase vzorcev izdelanih iz starega lesa iz kozolca primerljiva z izgubo mase kontrolnih vzorcev izdelanih iz sveže posekane smrekovine. Do podobnih ugotovitev smo prišli tudi pri mehanskih testih. Glede na dobljene rezultate naše naloge lahko zaključimo, da ima star les iz kozolca velik potencial za ponovno uporabo. M SORA has demolished an old wooden hayrack in the Sedej valley in Opale village near Žiri. From the obtained wood, the company develop and manufactures new wooden windows. For the research purposes, approximately 1 m long beams, rails and rafters were used. Most of the samples taken were made of spruce wood, and one was made of cherry wood. Larger samples were prepared for the testing of durability to wood decay fungi according to the standard (EN 113) procedure and samples for testing the mechanical properties. Three-point bending test and compressive strength tests were performed. In the research, the density of the wood, the mass loss, the moisture content of the specimens after exposure to fungi, were determined. Mass loss after exposition to white and brown rot decay fungi showed that the mass loss of samples made from old used wood was comparable to the mass loss of control samples made from fresh sawn spruce. Similar findings were obtained at mechanical tests. Based on the results of our work, we can conclude that old used wood has great potential for reuse in different applications.

V diplomskem delu smo obravnavali vpliv notranje nege na tlačno trdnost betona visoke trdnosti. Betoni visoke trdnosti imajo višjo tlačno trdnost kot običajni betoni, zato lahko elementi iz omenjenih betonov, v primerjavi z elementi iz običajnega betona, enako obtežbo pri manjšem prečnem prerezu elementa. Ker pa visoko tlačno trdnost zagotavljamo predvsem z nizkim vodo-cementnim razmerjem, so ti betoni podvrženi večjemu krčenju in posledično razpokam. Deformacijo krčenja v zgodnjem obdobju lahko močno omilimo z notranjim negovanjem betona, s pomočjo notranjih rezervoarjev vode, kar pa lahko negativno vpliva na tlačno trdnost betona. Izvedli smo eksperimentalno raziskavo, v okviru katere smo testirali in analizirali vpliv različnih notranjih rezervoarje vode v betonih na velikost njihove tlačne trdnosti. Kot notranji rezervoar vode smo uporabili predhodno namočen naraven lahek agregat lehnjak, predhodno namočen umeten lahek agregat, s komercialnim imenom Liapor, predhodno namočena bazaltna vlakna, predhodno namočena celulozna vlakna. Notranje rezervoarje vode v beton vgradimo tako, da del običajnega agregata zamenjamo s predhodno namočenim medijem. Ugotovili smo, da je predhodno namočen lahek agregat, naraven in umeten, omogočil betonu višjo tlačno trdnost glede na primerjalni beton brez lahkega agregata, vgradnji predhodno namočenih bazaltnih in predhodno namočenih celuloznih vlaken pa sta na tlačno trdnost betona vplivali negativno. In this thesis the influence of internal curing on the compressive strength of high strength concrete was examined. Such concretes have much higher compressive strength than conventional concretes, so they can withstand the same load with a smaller cross-section of the element. However, since the high compressive strength is ensured primarily by the low water-cement ratio, these concretes are subject to greater shrinkage and consequently, cracks. Early shrinkage deformation can be greatly alleviated by the internal curing of the concrete, by means of internal water reservoirs, which in turn may adversely affect the compressive strength of the concrete. An experimental study was conducted in which the phenomenon of internal reservoirs in high strength concrete was tested and analyzed. As an internal water reservoir we used pre-soaked natural tufa aggregate, pre-soaked artificial lightweight Liapor aggregate, pre-soaked basalt fibers and pre-soaked cellulose fibers. Internal water reservoirs were placed in concrete by replacing part of a conventional unit with a pre-soaked medium. We found that pre-soaked lightweight aggregate, natural and artificial, gave concrete a higher compressive strength compared to non-lightweight aggregate concrete, and placement of pre-soaked basalt and presoaked cellulose fibers had a negative effect on the compressive strength of concrete.

Round Robin Testing (RRT) is a well-known method for assessing the reproducibility of a test or verification of a new test procedure of almost any kind. In the EU funded network COST Action TU1404 ‘‘Towards the next generation of standards for service life of cement-based materials and structures”, an Extended Round Robin Testing program (RRT+ ) was planned as a fundamental tool to obtain input data for a range of concrete properties and validate non-standardised testing techniques. In this paper, detailed information on the planning, conduction and analysis of Phase 1 of the RRT+ is presented. The aim of Phase 1 was to define and confirm the best practice for creating a comparable reference concrete mix for RRT programmes. With a total of 45 laboratories from Europe, Japan and Canada, RRT+ was one of the most extensive round robin testing programmes targeting cement-based materials., The authors also acknowledge the financial support of EDF, France; CEVA Logistics, Austria and Germany; OeBB Infra, Austria; Staten Vegvesen, Norway and Schleibinger Gerate, Germany. The support of the research network COST TU1404 (COST Association) is also gratefully acknowledged.

V diplomski nalogi smo želeli raziskati in v praksi uporabiti materiale, ki bi s svojo dostopno ceno, dobrimi mehanskimi karakteristikami in obstojnostjo ter enostavno pripravo omogočali širok spekter uporabe v mozaični umetnosti. Trenutno na trgu najdemo mozaične materiale, ki dosegajo zelo visoke cene, in jih je največkrat treba dobavljati iz tujine. Po pregledu literature in predhodnih raziskavah smo se odločili, da se osredotočimo na izdelavo vzorcev pripravljenih z mineralnim materialom s tržnim imenom Kremenit ter vzorcev pripravljenih z epoksidnimi vezivi Epox 210 in Aquares. Karakteristike vzorcev smo ovrednotili s pomočjo tlačne, upogibne natezne in cepilne natezne trdnosti ter zmrzlinske odpornosti. Pripravili smo vzorce različnih sestav. Razmerja sestavin smo spreminjali z dodajanjem različnih polnil, dodatkov in pigmentov, pri čemer smo že pri fazi priprave izpostavili prednosti in slabosti posameznega materiala. Prednost mineralnega materiala Kremenita je njegova enostavna priprava, hitro strjevanje in doseganje barvnih odtenkov, ki so zlasti primerni za konserviranje- restavriranje starih mozaikov. Slabše je obstojen v vodi, z dodajanjem pigmenta pa se mu bistveno poslabšajo mehanske karakteristike. Pri epoksidnih vezivih Epox 210 in Aquares dosegamo visoko intenziteto barve, kar je prednost pri izdelavi sodobnih mozaikov. Smoli sta odlično obstojni v vodi, poleg tega večina uporabljenih pigmentov bistveno ne spremeni tlačne in upogibne natezne trdnosti materiala. Slabost epoksidnih veziv, v primerjavi z mineralnimi vezivi, je nekoliko višja cena in pa slaba sposobnost cepitve, kar je ključna lastnost pri pripravi mozaičnih kock. To slabost smo poskušali odpraviti z dodajanjem polnil, vendar učinkovite cepitve na manjše kose kljub dodajanju različnih polnil praviloma nismo uspeli doseči. In this final thesis we wanted to study application of materials with wide range of use in mosaic art. These materials should possess good mechanical properties and be affordable and simple to produce. Mosaic materials currently available are known to be expensive and must mostly be supplied from abroad. After reading through literature and previous studies, we choose to focus on preparation of samples from a mineral material industrially known as Kremenit, and epoxy adhesives labeled as Epox 210 and Aquares. We prepared and tested samples of materials varying in composition, their variation caused by adding different fillers, additives and pigments. We tested them on compression, bending, splitting, impact, and freezing resistance. After that we described the advantages and disadvantages of every material. Advantages of the mineral material Kremenit included easy preparation, short curing time and simplicity when adding pigments in order to achieve wanted colouring of the material. These properties make it usable in the conservation and restoration of old mosaics. Its disadvantages are low water resistance and deterioration of its mechanical properties. Advantages of binders based on Epox 210 and Aquares include the possibility to achieve high intensity of colouring, which is an advantage in composition of modern mosaics. Both resins have an excellent water resistance and addition of pigment does not change mechanical properties of final product. The disadvantages, compared to the mineral material, are a somewhat higher price and poor splitting properties. We tried to improve those qualities by adding different fillers to each resin, but we did not achieve the splitting of the product into smaller pieces in most cases.

Proizvodnja cementa je velik porabnik energije in hkrati povzroča emisije toplogrednih plinov v ozračju, ki so odgovorne za globalno segrevanje. Za doprinos k rešitvi tega problema se številne raziskave v svetu osredotočajo na uporabo odpadnih in sekundarnih materialov ter surovin, ki imajo lastnosti, podobne portlandskemu cementu, ter jih je mogoče dodati v beton kot delno zamenjavo cementa, ne da bi pri tem ogrozili njegovo trdnost in trajnost. V diplomskem delu smo kot delno zamenjavo portlandskega cementa uporabili železarsko žlindro, sekundarno surovino, ki nastane pri proizvodnji železa v visokih pečeh. V okviru eksperimentalnega dela smo žlindro v laboratorijskem mlinu zmleli do ustrezne finosti, ki smo jo kontrolirali z Blainovim permeabilimetrom. Po recepturi za standardno cementno kašo smo izdelali preizkusne vzorce, kjer smo cement nadomestili z 10, 20, 30, 40 in 50 masnimi odstotki drobno mlete žlindre. Na vseh vzorcih smo izvedli standardne upogibne in tlačne preizkuse. Na podlagi pridobljenih rezultatov lahko zaključimo, da delni nadomestek cementa z drobno mleto žlindro ni bistveno vplival na spremembo mehanskih lastnosti preizkusnih vzorcev. Glede na rezultate v diplomskem delu predvidevamo, da se z uporabo drobno mlete žlindre lahko tudi do 50 % zmanjša poraba cementa in s tem cena betonske mešanice. The production of cement is a major consumer of energy and also causes greenhouse gas emissions into the atmosphere. These are responsible for global warming. As a contribution to finding a solution for this problem, several researches focus on the use of waste, secondary and raw materials. These have similar properties than Portland cement and it is possible to add them to the cement as a partial substitution thereof, without affecting its soundness and durability. In the dissertation, steel slag a secondary raw material produced in the process of steel production in blast furnaces, was used as a partial substitution for Portland cement. In the experimental part, the slag was ground in a laboratory mill until it reached the optimum fineness, which was measured with the Blaine permeability meter. According to the recipe for cement pulp, samples were produced where cement was substituted with 10, 20, 30, 40 and 50 weight percentage of finely ground slag. Standard bending and compressive strength tests were carried out on the samples. Based on the acquired results it can be concluded that the partial substitution of cement with finely ground slag did not significantly influence the mechanical properties of the samples. The results acquired in the dissertation suggest that the use of finely ground slag can reduce the consumption of cement by 50% and therefore also reduce the price of the concrete mix.

Namen diplomske naloge je bila karakterizacija mikrostrukture ter mehanskih in toplotnih lastnosti dentalnega kompozitnega materiala za zalivke, saj so to ene od najpomembnejših lastnost, ki jih morajo imeti materiali za ta namen. Diplomsko delo je sestavljeno iz teoretičnega in eksperimentalnega dela. V teoretičnem delu so opisi dentalnih materialov, predstavitev kompozitov v dentalni medicini ter vse splošne lastnosti kompozitov. Opredeljen je tudi pomen kompozitov v dentalni medicini in njihov nadaljnji razvoj. V eksperimentalnem delu smo izdelali valje oziroma diske iz kompozita, ki se uporablja za zalivke, in sicer na dva načina, s polimerizacijo po plasteh in polimerizacijo površine celotnega volumna testnega valja. Izmerili smo tlačno trdnost ter ugotovili, da ima kompozit, izdelan po plasteh, višjo tlačno trdnost. Najverjetneje je to zaradi bolj kvalitetne izdelave vzorca v primerjavi z vzorcem, izdelanim s polimerizacijo površine celotnega volumna testnega valja, kjer je popolna polimerizacija potekala samo v površinskih plasteh, v jedru pa najverjetneje ni prišlo do popolne polimerizacije. Kompozitnim vzorcem smo izmerili tudi trdoto in toplotno prevodnost. Trdota po Vickersu je znašala 120 HV, toplotna prevodnost pa 0,5168 W/mK. Z vrstičnim elektronskim mikroskopom (SEM), opremljenim z detektorjem EDXS, smo analizirali površino vzorca izdelanega s polimerizacijo po plasteh in vzorca, kjer smo polimerizirali površino celotnega volumna testnega valja. Ugotovil smo, da ima vzorec, izdelan po plasteh, na površini razpoke. Opravili smo tudi mikrostrukturno analizo ter določili mikrostrukturne sestavine. Ugotovljeno je bilo, da je kompozit pretežno sestavljen iz delcev stekla iz BaO, SiO2 in Al2O3. Vmes pa najdemo tudi delce itrebijevega trifluorida. Matico iz organskega materiala pa z EDXS ni mogoče analizirati. Na osnovi opravljenih preiskav smo ugotovili, da imajo kompozitne zalivke ustrezne fizikalne in mehanske lastnosti za nadomestitev trdih zobnih tkiv, ki pa so pogojene s tehniko in kakovostjo izdelave. Kompozitne zalivke morajo biti izdelane natančno, v absolutni osušitvi – to je v odsotnosti tekočin (npr. vode, sline, krvi), in ob doslednem upoštevanju tehnike za izdelavo kompozitnih zalivk. Le tako bo zagotovljeno ustrezno tesnjenje kompozitne zalivke, in onemogočen nastanek nepravilnosti kot so spremembe v zgradbi materiala in nastanek razpok v materialu. The purpose of diploma work was the characterisation of the microstructure, mechanical properties and thermal characteristics of the dental composite for fillings since these are the most important features of the materials for this purpose. The diploma work consists of theoretical and experimental work. In the theoretical part dental materials, mostly composite materials and their properties are described. The importance of the composites in dental medicine is also defined, as well as their further development. The testing samples in the shape of cylinder made of dental composite were prepared by two different routes which are explained in the experimental, i.e. by polymerisation of single layers from which the sample is composed and by polymerisation of the surface across the whole volume of the sample. It was found that the composite produced by layers had higher compressive strength. This is probably due to a better quality of the sample made by polymerisation of the single layers in comparison to the sample made by polymerisation of the surface across the whole sample. Hardness and thermal conductivity were also measured. The Vickers hardness was 120 HV and thermal conductivity was 0,5168 W/mK. The surface of both samples was analysed with scanning electron microscope (SEM) with attached EDXS detector. Sample which was made by polymerisation of the surface across the sample showed not only porosity but also cracks on the surface. The microstructure analysis of the composite materials was performed and microstructure constituents were determined. It was found that the composite is mainly consisted of glass particles made of BaO, SiO2 and Al2O3. However, some particles of ytterbium trifluoride were also observed. The matrix made of organic materials cannot be analysed with EDXS analysis. Based on performed tests, it was found that the composite fillings have appropriate physical and mechanical properties for the substitution of the solid tooth tissues however, the properties strongly depend on the quality of the production. The composite filling must be made precisely in absolute dry conditions, i.e. in the absence of any liquids (e.g. water, saliva, blood) and with strict consideration and following of the procedures for making composite fillings. Only in this way the appropriate sealing of the composite filling will be ensured and the irregularities such as changes in the material structure and the formation of cracks will be avoided.

In order to simulate and study the corrosion effects on the compressive strength of cemented soils that could be exposed in a polluted environment, a series of tests were conducted on cemented soil blocks cured with different concentrations of H2SO4, MgSO4, and Na2SO4 solutions. The test results show that the corrosion degree generally increases with the corrosion time and the solution concentration, while the compressive strength decreases with the increasing corrosion degree. The corrosion degree is highest for the Na2SO4 solution, followed by the MgSO4 and H2SO4 solutions. Namely, when the SO4 2- ion exists in a solution, the corrosion degree for the positive ions follows this descending order: Na+, Mg2+, and H+. X-ray diffraction (XRD) phase analyses were performed for the cemented soil samples after corrosion and ionic concentrations. The results show that the compressive strength decreases with an increase of the Mg2+ concentration in the MgSO4 solution and the Na+ concentration in the Na2SO4 solution. At the same time, the strength increases with an increase of the pH value of the H2SO4 solution. Based on the chemical analysis results, the corrosion of H2SO4 or MgSO4 solutions on cemented soils is deemed as a composite action involving the combined resolving and crystallizing corrosion processes. Furthermore, the corrosion of the Na2SO4 solution of cemented soil is a composite action consisting of dissolving and crystallizing. Izveden je bil niz preizkusov na blokih cementiranih zemljin izpostavljenih različnim koncentracijam raztopin H2SO4, MgSO4 in Na2SO4, z namenom simulacije in preučitve učinkov korozije na tlačno trdnost cementiranih zemljin, ki so lahko izpostavljene onesnaženemu okolju. Rezultati preizkusov kažejo, da se stopnja korozije splošno poveča s časom korozije in koncentracije raztopine, medtem, ko tlačna trdnost pada z naraščajočo stopnjo korozijo. Stopnja korozije je največja za raztopino Na2SO4, kateri sledita raztopini MgSO4 in H2SO4. Namreč, če v raztopini obstajajo SO4 2- ioni, stopnja korozije za pozitivne ione sledi v padajočem redu Na+, Mg2+ in H+. Po koroziji in ionski koncentraciji je bila z rentgenskimi žarki izvedena difrakcijska fazna analiza na vzorcih cementiranih zemljin. Rezultati kažejo, da tlačna trdnost pada z večanjem koncentracije Mg2+ v raztopini MgSO4 in koncentracije Na+ v raztopini Na2SO4. Medtem, ko se trdnost veča z večanjem pH vrednosti raztopine H2SO4. Na osnovi rezultatov kemijskih analiz, se korozija raztopin H2SO4 ali MgSO4 na cementiranih zemljinah razume kot sestavljen učinek, ki vključuje kombinirane korozijske procese razpadanja in kristalizacije medtem, ko korozijo raztopine Na2SO4 sestavlja učinek raztapljanja in kristalizacije.

The effects of coconut fibre on the mechanical characteristics of lime-treated clay are investigated in this study. The lime-treated clay specimens were prepared with a variety of coconut-fibre contents, i.e., 0.5%, 1%, 1.5% and 2%, in terms of the weight of dry soil. The stabilized specimens were tested at 7, 28 and 90 days after the treatment in order to observe the evolution of the mechanical resistance with time. The results of the unconfined compressive strength tests were used to determine the relationships between the compressive strengths and the indirect tensile strengths of the stabilized soil. Furthermore, the optimum percentage of coconut fibre mixed in the soil/lime mixtures was 1% of the dry mass and reinforcement at 90 days increases the peak compressive strength and the indirect tensile strength. Coconut-fibre inclusion changes the brittle behaviour of the lime-treated clay soil to give it a more ductile character. V članku so predstavljeni izsledki študije vplivov kokosovih vlaken na mehanske karakteristike z apnom obdelanih glin. Z apnom obdelani vzorci gline so bili pripravljeni z različnimi vsebnostmi kokosovih vlaken, in sicer z 0.5%, 1%, 1.5% in 2% teže glede na suho težo zemljine. Časovni razvoj mehanskega odpora utrjenih vzorcev je bil opazovan tako, da so bili preizkušeni po 7, 28 in 90 dneh od dneva obdelave z apnom. Rezultati preizkusa enoosne tlačne trdnosti so bili uporabljeni za določitev odnosa med tlačno trdnostjo in indirektno natezno trdnostjo z apnom utrjene zemljine. Nadalje je bilo ugotovljeno, da je optimalni delež kokosovih vlaken zmešanih v zmeseh zemljina-apno enak 1% suhe mase ter, da je takšna ojačitev v 90 dneh zvišala najvišjo tlačno trdnost in indirektno natezno trdnost. Dodajanje kokosovih vlaken spremeni krhki odziv z apnom obdelane gline v bolj duktilnega.

Z vse bolj razširjeno uporabo visoko trdnih jekel pri izdelavi modernih komponent, predvsem v avtomobilski industriji, se povečuje tudi obremenitev preoblikovalnih orodij. Ta so izpostavljena kompleksnim obremenitvam kot so obraba, plastična deformacija in utrujanje, ki rezultirajo v nastanku poškodb in odpovedi orodja. Na splošno se kot osnovno lastnost karakterizacije orodja uporablja trdota, kar pa v zadnjem času ne zadošča. Potrebno je raziskovanje celotnega spektra mehanskih lastnosti, kakor tudi parametrov obrabne obstojnosti ter preoblikovalnosti. Preoblikovalna orodja so izpostavljena kombinaciji kompleksnih obremenitev. Da bi se ustrezno zoperstavili omenjenim obremenitvam in posledično z njimi nastalimi problemi, moramo poznati različne lastnosti materiala, vpliv legirnih elementov, proces toplotne obdelave in obnašanje materiala tekom le-te. Kljub temu, da je glavna mehanska lastnost trdota, pa na lastnosti preoblikovalnega orodja vplivajo še kombinacija tlačne in upogibne trdnosti ter lomne žilavosti, ki vplivajo na obrabno obstojnost, dobo trajanja orodja in njegovo vzdržljivost v industrijskem procesu. With the increased use of high strength steels, especially in the automotive industry, the load of the forming tools increases. These are exposed to complex loads such as wear, plastic deformation and fatigue, which result in damage and tool failure. In general, hardness is used as the basic characteristic of the tool, which, however, is not sufficient anymore. It is necessary to take into account the entire spectrum of mechanical properties and parameters, including wear resistance and formability. Forming tools are exposed to a combination of complex loads. In order to adequately address these loads and consequently the associated problems, we need to know a large set of properties of the material, the influence of the alloying elements, the heat treatment process and the behaviour of the material during heat treatment and use. Although the main mechanical property is hardness, it is required to know also the combination of compressive and bending strength as well as fracture toughness to successfully characterize tool performance. All these properties influence on tool wear resistance, lifetime and durability during the industrial processes.

Namen magistrske naloge je preverjanje obstojnosti različnih betonov in malt, ki so podvrženi agresivnim pogojem okolja, z vzporednim nenehnim preverjanjem nekaterih mehanskih in fizikalnih lastnosti (s kontroliranim razvojem lastnosti). Kontrolirane mehanske lastnosti betonov in malt zajemajo tlačno, upogibno in cepilno natezno trdnost ter dinamični modul elastičnosti. Skupno betonom in maltam so enake sestavine in vodo-cementno razmerje, ki znaša 0,45, pri čemer malta ne vsebuje grobega agregata. V ta namen smo v okviru magistrske naloge preučevali vpliv kemijske alkalno-karbonatne reakcije (ACR) na mehanske lastnosti, spremembo mase in dolžine maltnih vzorcev. Malte so bile pripravljene iz štirih različnih karbonatnih agregatov nazivne frakcije 0/4 mm v kombinaciji z dvema različnima cementoma. Preizkušanci v obliki prizem (40x40x160 mm) so bili skozi obdobje 14 mesecev izpostavljeni različnim pospešenim pogojem staranja (deionizirani vodi ali 1 M raztopini natrijevega hidroksida pri temperaturi 20 °C ali 60 °C). Na betonih smo preverjali njihovo odpornost v primeru ciklične obtežbe zmrzovanja in tajanja, vse do 250 ciklov. Vzporedno smo določili tudi njihovo tlačno trdnost, cepilno natezno trdnost in odpornost proti prodoru vode, vendar v tem primeru samo pred začetkom obremenjevanja s cikli zmrzovanja/tajanja, katerih vpliv smo preverjali s pomočjo določitve dinamičnega modula elastičnosti betona. Ugotovili smo, da ACR vpliva na mehanske lastnosti dolomitnih malt, ne pa tudi na njihovo spremembo mase in dolžine, zato smo zaključili, da ACR ni ekspanzijska reakcija. Prav tako smo pokazali, da imajo vsi obravnavani betoni visoko odpornost proti zmrzovanju/tajanju in visoko vodotesnost, kar pomeni, da smo zasnovali betonske mešanice, ki so sposobne zagotavljati dolgo življenjsko dobo armiranobetonskih elementov – tudi 200 let in več. The purpose of the master's thesis is to verify the durability of concretes and mortars that are exposed to aggressive environmental conditions, with controlled development of their physical and mechanical properties. Controlled mechanical properties of concretes and mortars are compressive, bending and splitting tensile strength and dynamic modulus of elasticity. What the concretes and mortars have in common are the same components and a water-cement ratio of 0,45, where mortars do not contain coarse aggregates. In this thesis, we try to establish the impact of the chemical alkali-carbonate reaction (ACR) on mechanical properties, weight and length of mortar samples. The mortars were made with four different carbonate aggregates with the nominal fraction 0/4 m, and by combining two different cements. The prism-shaped samples (40x40x160 mm) were exposed to different accelerated ageing conditions over a period of 14 months (a solution of deionised water or 1 mol sodium hydroxide, and a temperature of 20 °C or 60 °C). We also tested the resistance of the concrete samples in the case of a cyclic freezing and thawing load, up to 250 cycles. Before the freezing/thawing test, we also tested their mechanical properties. We determined their pressure strength, splitting tensile strength and resistance to water penetration. However, we performed these tests before the start of loading freeze/thaw cycles, the influence of which was checked by determining the dynamic modulus of elasticity of concrete. The results have shown that ACR affects mechanical properties of dolomite mortar samples, but not their mass and length. Therefore, we have concluded that ACR is not an expansion reaction. We have also determined a high resistance to freezing/thawing and high watertightness of all concrete samples. This means that we have designed concrete mixtures that are capable of providing a long lifespan of reinforced concrete elements, even up to 200 years and more.

V sklopu diplomske naloge smo opravili preiskave na svežih in strjenih maltnih mešanicah, namenjenih izdelavi sanacijskih ometov. Glavni namen je bil pripraviti različne sestave malt za sanacijske omete, ki bodo dosegale čim večjo poroznost in paroprepustnost pri ustrezni tlačni trdnosti. Ugotoviti smo želeli, kako različna vrsta veziva in kemijski dodatki vplivajo na te lastnosti malt. V prvem delu diplomske naloge smo na podlagi izbranih razmerij med agregatom, vezivom in dodatki po več poizkusih dodajanja različnih količin vode dobili končne recepture mešanic. Kot kemijska dodatka smo uporabili superplastifikator in aerant, kot vezivo pa dve različni vrsti cementa in apno. Na svežih mešanicah smo raziskave opravili s standardizirano metodo določanja razleza na stresalni mizici ter določili prostorninsko maso malt in vsebnost por. V drugem delu smo na strjenih vzorcih starih 28 dni določili tlačno trdnost in merili difuzijo vodne pare. Vse rezultate, ki smo jih dobili s preiskavami, smo podali v preglednicah in na grafih. As part of this thesis, a test was made on fresh and hardened mortar mixtures aimed at preparing restoration renders. The main purpose was to prepare various compositions of mortar for restoration renders that would have the highest possible air content and water vapour permeability at adequate compressive strength. We wanted to find out how different types of binders and chemical admixtures affect these properties of mortars. Based on the given ratio between the aggregate, the binder and the admixtures, the first part of the thesis focuses on the final mixture compositions that were obtained after several attempts of adding different amounts of water to them. Superplasticizer and air entraining agent were used as chemical admixtures and as binders two different types of cement and lime were used. Research on the fresh mixtures was conducted with standardized methods of determining the flow value on the flow table, after which the density and porosity of mortar were determined. In the second part of the thesis, compressive strength and water vapour diffusion were tested on 28-day-old hardened samples. All the results obtained during the tests are given in tables and graphs.

Plastika je prisotna v številnih aplikacijah. Njena množična uporaba povzroča velike količine odpadkov, ki jih je potrebno ustrezno predelati oz. reciklirati. Ena od možnosti je tudi recikliranje odpadne plastike in uporaba v gradbeništvu – v betonu. V sklopu magistrske naloge smo izvedli preiskave na odpadni plastiki tipa PE, PP in PVC. V prvem delu smo opravili pregled dosedanjih raziskav na področju uporabe plastike v betonu. Sledila je karakterizacija odpadne plastike za potrebe izdelav receptur betona. V zadnjem delu preiskav smo v betonu delno nadomestili naravni agregat z odpadno plastiko in opravili standardne laboratorijske preiskave. Plastics have found uses in various applications. Their widespread use results in enormous amounts of waste which must be properly recycled or recovered. One possibility is the recycling of plastic waste and its use in concrete. As a part of my Master's thesis, we carried out our research on waste plastics such as PE, PP and PVC. In the first part of it, we reviewed the current research on the use of plastics in concrete. This was followed by plastic waste characterization in order to make concrete recipes. In the final part of our research, we partially replaced natural aggregate in concrete with waste plastics and subjected it to standard laboratory tests.

Velike količine gradbenih odpadkov, ki nastajajo pri raznih sanacijah, rušitvah in obnovah objektov, predstavljajo velik problem za okolje. V diplomski nalogi smo preučili možnost uporabe recikliranega betona kot agregata za proizvodnjo konstrukcijskih betonov. Reciklirani agregat smo pridobili iz rušenja betonske stene iz betonskih zidakov. Ruševine smo zdrobili z drobilcem in jih nato presejali na sejalni napravi na ustrezne frakcije in sicer 4/8, 8/16 in 16/31.5 mm, frakcijo 0/4 mm smo nadomestili z naravnim agregatom. Dobljeni reciklirani agregat smo uporabili za betonske mešanice po enotni recepturi z različni deleži frakcij agregata. Dobljenim preizkušancem, kockam s stranico 150 mm, smo v laboratoriju določili tlačno trdnost. Na podlagi dobljenih rezultatov smo ugotovili, da naš beton ne dosega vrednosti za proizvodnjo zahtevnejših konstrukcijskih elementov, lahko bi ga pa uporabili za stabilizacije tal, drenažne betone in druge nezahtevne betonske konstrukcije. Large quantities of construction waste generated at various renovations and demolitions of buildings represent a major problem for the environment. In this thesis, we studied the possibility of using recycled concrete as an aggregate for the manufacture of structural concrete. Recycled aggregates were obtained from the demolition of the concrete walls from concrete blocks. Ruins were crushed by the grinder and then screened in screening machines at the appropriate fractions, namely 4/8, 08/16 and 16 / 31.5 mm, fraction 0/4mm has been replaced with natural aggregates. The resulting recycled aggregate was used for the concrete mix at a single recipe with different proportions of fractions of aggregates. Obtained test specimens, cubes with side measure 150 mm, were tested for compressive strength in the laboratory. Based on the results, we found that our concrete does not reach the level of production of complex structural elements, but could be used for soil stabilization, drainage concrete and other unpretentious concrete structures.

V diplomskem delu smo analizirali prisotnosti vlaken iz odpadnih PET plastenk na različne lastnosti svežega in strjenega betona. Vlakna smo pridobili s preprostim mehanskim rezanjem PET plastenk s ciljem čim manjšega vložka energije za izdelavo le-teh. Izdelali smo vzorce vlaknastega betona z 0.5 %, 1.0 % in 1.5 % volumskim deležem PET vlaken, za primerjavo rezultatov pa tudi vzorec vlaknastega betona z dodanimi komercialno dobavljivimi polipropilenskimi STRUX vlakni z 0.5 % volumskim deležem vlaken ter referenčni vzorec betona brez vlaken. Vsa vlakna smo dodali v suho betonsko mešanico. Izvedli smo osnovne preiskave svežih betonskih mešanic, na strjenih betonskih vzorcih pa tritočkovni upogibni preizkus ter preiskavo tlačne trdnosti in prostorninsko maso. Rezultati so pokazali, da dodana PET vlakna izboljšajo upogibno trdnost vlaknastega betona, medtem ko je vpliv na tlačne trdnosti vlaknastega betona praktično zanemarljiv. Najvišjo upogibno trdnost smo ugotovili na vzorcu z 1.5 % volumskim deležem PET vlaken. Najenakomernejšo porazdelitev rezultatov smo dosegli pri vzorcih z nižjim volumskim deležem vlaken. Beton se je po nastanku prve razpoke obnašal duktilno. In the thesis the fibrous concrete reinforced with recycled PET bottles fibers was analysed. We analysed various properties of fresh and hardened concrete. The fibers were obtained by a simple mechanical cutting of PET bottles, with an emphasis on minimizing energy input for the fibers preparation. Samples of fibrous concrete with 0.5 %, 1.0 % and 1.5 % volume fraction of PET fibers were prepared. For comparison, a sample of fibrous concrete with the addition of a commercially available polypropylene fiber STRUX with 0.5 % volume fraction of STRUX fibers was prepared. A reference sample of concrete without fibers was also prepared. All fibers were added to a dry concrete mixture. We conducted a basic investigation of fresh concrete mixes. On hardened concrete a three-point bending test was performed and tests to determine the compressive strength and volume weight. The results showed that the added PET fibers improve the bending strength of the fibrous concrete, while the influence on the compressive strength of the fibrous concrete is almost negligible. The maximum flexural strength was measured in the sample with 1.5 % volume fraction of the PET fibers. Uniform distribution of the results has been achieved in samples with a lower volume fraction of PET fibers. The behaviour of concrete after the formation of the first crack was ductile.

Na začetku diplomskega dela se bomo dotaknili zgodovine materialov, s katerimi so gradili naši predniki. V nadaljevanju bomo razložili sistematiko delitve mineralnih veziv, ki jih poznamo danes ter predstavili nekatere njihove mehanske in fizikalne lastnosti. Nato bomo podrobneje obravnavali veziva, kot so elektrofiltrski pepel, metakaolin in naravni pucolan, ter le-te v laboratoriju zmešali, izmerili gostoto ter opravili preizkus tlačne in upogibne trdnosti. V zadnjem delu bomo vse rezultate zabeležili, jih analizirali in primerjali med seboj. At the beginning of the thesis we will talk about the history of materials, which were built by our ancestors. Here we are going to explain the scheme of division of mineral aggregates, which we know today, and present some of their mechanical and physical properties. After we will discuss about binders, such as fly ash, metakaolin and natural pozzolan. We will mix those binders in the laboratory, measure their density and perform the compressive and flexural strength test. In the final part we will record all results, analyze them and compare with each other.

V magistrski nalogi smo se ukvarjali z razvojem samozgoščevalnega betona iz lahkega agregata s predpisanimi lastnostmi, kot sta razred tlačne trdnosti in največja ciljna gostota betona. Pri določanju samozgoščevalnih lastnosti smo kot osnovno orodje uporabili meritve reoloških lastnosti in izbiro optimalnega območja napetosti na meji tečenja in plastične viskoznosti. V prvem delu naloge prikazujemo lastnosti in specifikacije lahkega agregata in lahkoagregatnega betona. Te podatke smo pridobili na podlagi pregledane strokovne literature in standardov. V tem delu podajamo še nekatere splošne razlage o reologiji betona in modelih za opis tekočin ter predstavimo meritve z ultrazvokom in meritve toplotnega toka. Drugi del naloge, ki predstavlja jedro naloge, je obširnejši in je naravnan eksperimentalno. Najprej so prikazane preskusne metode in načini izvajanja preiskav ter izmerjene lastnosti materiala. Sledi analiza rezultatov meritev. Betonske mešanice smo razdelili v dve skupini. Najprej smo obravnavali preliminarne mešanice, ki so služile kot priprava za glavno skupino mešanic. Pri glavni skupini mešanic smo analizirali vpliv različnih parametrov na reološke lastnosti svežih cementnih kompozitov, kar prikazujemo z reografi. Nato smo izbrano betonsko mešanico vgradili v steno dimenzij 100 cm x 230cm x 6 cm. Homogenost vgrajenega betona smo ocenili z meritvami z ultrazvokom, njegovo izolativnost pa z meritvami toplotnega toka. Preiskave so bile opravljene v okviru sodelovanja s podjetjem, ki uporablja takšne betone v praksi. The aim of the master thesis was to develop lightweight self-compacting concrete made of lightweight aggregate and with declared properties, such as compressive strength class and maximal target density. Self-compacting properties were determined by measuring rheological properties and selecting the optimum range of yield stresses and plastic viscosities as a result of these measurements. In the first part of the thesis properties and specifications of lightweight aggregate and lightweight concrete are given. The data were obtained using relevant literature and standards. Common explanations about rheology of concrete and models for the description of liquids are also given, along with presentation of ultrasound testing and thermal current measurements. The second part of the thesis, which is experimental, represents the main part of my work. First the used test methods are given and the testing protocols are described, with obtained results of the tests. After that the test results are analysed. Concrete mixtures were divided in two groups. Preliminary concrete mixtures were first tested in order to define the composition of the main group of the mixtures. For the main mixtures rheological properties were first measured for different influencing parameters and presented in the form of rheographs. Then selected mixture was used to cast a concrete wall of 100 cm x 230 cm x 6 cm. The homogeneity of concrete in the wall was evaluated using ultrasound testing. The thermal insulation properties of the concrete were evaluated using thermal flow measurements. The study was carried out in the framework of cooperation with an enterprise that uses such concretes in practice.

Betoni visoke trdnosti imajo majhno vodovezivno razmerje, zato je njihovo zgodnje avtogeno krčenje večje. V diplomski nalogi smo opisali zmanjševanje le-tega s pomočjo predhodno namočenega lahkega agregata, različnih frakcij in jeklenih vlaken. V okviru laboratorijskih raziskav smo merili avtogeno in celotno krčenje betonov visoke trdnosti. Iz dobljenih vrednosti smo izračunali prispevek krčenja zaradi sušenja. Obravnavali smo tudi tlačne trdnosti strjenega betona posameznih betonskih mešanic in opazovali vpliv vsebnosti lahkega agregata in jeklenih vlaken na njeno velikost. Največji doprinos k zmanjšanju krčenja je imela notranja nega s predhodno namočenim lahkim agregatom. Ugotovili smo, da se je beton, ki je vseboval jeklena vlakna in notranje rezervoarje vode v obliki predhodno z vodo namočenega lehnjaka, frakcije 24 mm, krčil najmanj in dosegal največje tlačne trdnosti glede na primerjalne betone. Due to its low water/cement ratio, high-strength concrete has a more pronounced early-age autogenous shrinkage. This thesis studies how to mitigate that by means of pre-soaked lightweight aggregate, various fractions and steel fibers. In the experimental part of the study, we measured the autogenous and total shrinkage of high-strength concrete, and used the results to calculate the contribution of drying shrinkage. We also measured the compressive strength of hardened concrete mixtures, and studied the influence of lightweight aggregate and steel fiber content on the compressive strength. Internal curing with pre-soaked lightweight aggregate proved to be the best shrinkage mitigator. We found out that the concrete which was reinforced with steel fibers and included internal water reservoirs in the form of pre-soaked tuff of 2 to 4 mm had the lowest shrinkage and the highest compressive strength of all the compared concrete mixtures.

Na državnem cestnem omrežju Republike Slovenije je zaradi dotrajanosti omejena skupna dovoljena masa vozil na 15 premostitvenih objektih. Nastala situacija je posledica konstantnega krčenja sredstev za državne ceste v zadnjih letih, zato potrebne ter že načrtovane sanacije niso bile izvedene. Rešitev nastalih težav je izključno sanacija premostitvenih objektov. Panoga gradbeništvo je tipično storitvena dejavnost in ena izmed pokazateljev vlaganja države v infrastrukturo. Gradnja večine objektov predstavljajo obsežna in kompleksna dela. Problem se kaže v obvladovanju informacij, ki naraščajo z obsegom in številom projektov. Gradbena podjetja uporabljajo različna informacijska orodja, ki jim lajšajo načrtovanje in spremljanje procesa gradnje, tako se pojavi nepovezljivost med posameznimi orodji. Posledice tega so nepreglednost podatkov, nezmožnost avtomatiziranega prenosa podatkov ter vprašljiva kakovost in varnost posameznih podatkov. V prvem delu diplomskega dela smo na splošno predstavili problematiko premostitvenih objektov z vidika poškodb ter obrazložili pomembnost sprotnega ugotavljanja in saniranja poškodb. Na podlagi konkretnega primera (most Dolsko) smo podali opis poškodb ter predlog sanacijskih ukrepov. V nadaljevanju dela je predstavljena priprava projekta za izdelavo terminskega plana in ponudbenega tehno-ekonomskega elaborata. Priprava vsebuje: popis del, strukturo projekta (WBS) in lokacijski potek del. Pri izdelavi popisa del in strukturiranju projekta sta bili uporabljeni programski orodji Xpert in MS Project. V sodelovanju s projektantom smo izdelali lokacijski potek izvedbe del, ki služi kot pomoč pri natančnejši izdelavi terminskega plana. On the Slovenian national road network a total of 15 bridges have a weight limit restriction due to their poor condition. Their condition is a result of cuts in funding of remedial works in recent years consequently already planned remedial works were not undertaken. To remedy the problem rehabilitation of these bridges needs to be performed. Construction industry is a typical business activity and one of the key indicators of state investment in infrastructure. The construction of most structures represents the extensive and complex range of activities. The problem is reflected in the management of information, which increases with the size and number of projects. Construction companies use different IT tools that facilitate their planning and monitoring of the construction processes which may result in bad connectivity between different tools used. The result is a lack of transparency of information, inability to automate data transfer, questionable quality and safety of data. In the first part of the thesis general problems related to damage of bridges and the importance of their assessment and remediation are presented. Based on the actual case (Dolsko bridge) the description of common types of damages and a proposal for remedial action are discussed. The second part of the thesis presents the preparation of the project bill of quantities as a tender documentation. Preparation includes: project scope definition as work breakdown structure (WBS) and location of the course. Structured bill of quantities is prepared using Xpert project management tool and exported to MS Project. In collaboration with the designers, a locational course of execution of works, which serves as an aid in the production of accurate schedule was created.

Glavni namen diplomske naloge je na podlagi ultrazvočnih meritev formiranja strukture materialov s cementnim vezivom ugotoviti vpliv mehanskega poseganja v strukturo v smislu občutnega vplivanja na vezanje in zgodnji razvoj trdnostnih karakteristik materiala. Proučevali smo predvsem spremembe mehanskih lastnosti: elastični modul, tlačno trdnost, konsistenco in čas vezanja. Tematike vpliva mehanskih posegov v strukturo materialov s cementnim vezivom (t.j. cementnih past, malt, betonov) na kakovost in mehanske lastnosti v odvisnosti od časa smo se lotili z vidika potreb po kvalitetni vgradnji in zagotavljanju ustreznih mehanskih lastnosti. Zanimal nas je vpliv v primerih kadar materiala ne vgradimo takoj po pripravi (dolg transport ali morebitne druge okoliščine, ki ne omogočajo takojšnje vgradnje) in vpliv mehanskih posegov v strukturo pri določenih časih (ponovno mešanje, revibriranje). Čase v obdobju vezanja, pri katerih smo mehansko posegli v strukturo materialov s cementnim vezivom in čas vezanja posamezne mešanice smo določili z novo ultrazvočno metodo, ki temelji na razmerju največjih amplitud dveh prevladujočih frekvenc, ki se pojavita v frekvenčnem spektru vzdolžnega valovanja. Za potrebe dosega cilja diplomskega dela smo poleg ultrazvočne metode uporabili klasične preskusne metode za določitev tlačnih trdnosti in statičnega elastičnega modula. Za analizo razvoja dinamičnega elastičnega modula smo uporabili napravo GrindoSonic, ki temelji na principu indukcije valovanja v vzorcu. Konsistenco pa smo določevali vizualno. Na podlagi lastnih eksperimentalnih preiskav smo ugotovili, da naknadni mehanski poseg (ne glede na obdobje v fazi vezanja) v strukturo mešanic ne vpliva bistveno na končne mehanske lastnosti. Časi vezanja se v relativnem smislu ponekod celo skrajšajo. Vendar pa nam konsistenca v praksi ne omogoča kvalitetne vgradnje brez uporabe dodatkov (plastifikatorjev). The main purpose of the thesis, based on the ultrasonic measurements of the formation of the materials with cement binders, is to determine the impact of the mechanical intervention into the structure, in terms of the significant influence on the setting and early development of characteristic strength of material. During our research we mostly pursued changes in mechanical properties: elastic modulus, compressive strength, consistency and setting time. The issue of the impact (of the mechanical intervention into the structure of the cement paste, mortars and concrete) on the quality and on mechanical properties in relation to time was dealt with from the perspective of the demand for a better built quality as well as with the aim to provide adequate mechanical properties. As far as the impacts were concerned, we were particularly interested in cases, when material is not built in immediately after its preparation (long transport or any other circumstances which do not allow for immediate placing operation) as well as in the impact of the mechanical intervention into the structure at certain times (revibration, remixing). Setting times, when mechanical intervention into the structure of the material with binding agent took place, as well as setting time of a particular mixture, were determined by a new ultrasonic method, which is based on the highest ratio of the amplitudes of the two dominant frequencies, which appear in the frequency spectrum of longitudinal waves. In addition to the ultrasonic method, classical test methods were carried out as well in order to determine compressive strength and static elastic modulus and reach the objective of the thesis. For the purpose of analysis of the dynamic elastic modulus development we used GrindoSonic device, which is based on the principle of induction of the wave in the sample. Consistency was determined visually. On the basis of our experimental research, we found out that subsequent mechanical intervention (irrespective of the period at the stage of setting) into the structure of the mixtures, does not affect substantially the final mechanical properties. In some cases setting times are even shortened in relative terms. However, consistency in practice does not allow us to ensure high quality of placing operation without the use of additives (plastificators).

V diplomski nalogi se ukvarjamo s potencialno reakcijo med karbonatnim agregatom in cementnim vezivom. Ugotavljamo vpliv te reakcije na mehanske lastnosti strjenih betonov, izdelanih z različnimi karbonatnimi agregati. V ta namen smo zasnovali tri različne mešanice betona, eno z apnenčastim agregatom A in drugi dve z dolomitnim agregatom B in C. Betone smo izpostavili različnim pogojem pospešenega staranja pri starosti 7 ali 28 dni. Staranje preizkušancev je trajalo 28 dni. Vsak teden staranja smo določili tlačno in upogibno trdnost betonov ter dinamični modul elastičnosti. Dobljene rezultate smo analizirali z vidika potencialnega vpliva alkalno-karbonatne reakcije na mehanske lastnosti betona. This thesis deals with a potential reaction between carbonate aggregate and cement binder. We try to establish the impact of this reaction on the mechanical properties of hardened concrete made with different carbonate aggregates. To this aim, we designed three different mixtures of concrete, one with limestone aggregate A and the other two with dolomite aggregates B and C. Concretes were exposed to different conditions of accelerated aging at the age of 7 or 28 days. The aging of the test specimens lasted 28 days. Each week of aging compressive and flexural strengths of concrete were determined, and the dynamic modulus of elasticity was measured. The results thus obtained were analysed in terms of the potential impact of alkali-carbonate reactions on the mechanical properties of concrete.

Namen diplomskega dela je bil preveriti možnost uporabe stranskih produktov, ki nastanejo pri izgorevanju premoga v termoelektrarni Trbovlje za zalivne mase kanalov in geosond in jih primerjati z zalivnimi masami, ki jih je mogoče kupiti na trgu. Zalivna masa je mešanica polnila, veziva in vode, ki mora izpolnjevati zahteve glede pretočnosti, volumenske stabilnosti, trdnosti in druge, za specifične namene rabe, zahtevane lastnosti. Izvedli smo laboratorijske preiskave na različnih mešanicah stranskih produktov izgorevanja premoga ter na referenčni zalivni masi. Preizkusili smo volumensko stabilnost svežih mešanic, z reometrom smo izmerili njihovo viskoznost, opravili meritve vodovpojnosti po Enslinu, meritve adsorpcije na organsko barvilo metilen modro, po Atterbergu smo ugotavljali mejo židkosti bentonita ter merili tlačne trdnosti staranih mešanic. Ugotovili smo, da ima količina dodane vode velik vpliv na rezultate vseh preiskav, da je njen vpliv nelinearen, da bentonit kot dodatek dobro vpliva na stabilnost sveže mešanice, cement pa pripomore k povečanju trdnosti. Žlindra kot polnilo ni izkazala ugodnih rezultatov, prvič zato, ker bi jo morali odsejavati pred uporabo, drugič pa zato, ker ne veže in mešanice z žlindro ne dosegajo ustreznih trdnosti. The purpose of the thesis was to investigate the coal combustion products - CCP- from the brown coal burning thermo-power plant as a component for grouts for backfilling trenches and geo-sounds. The grout is a mixture of inert material, hydraulic binder, additives and water. It must fulfil the criteria of viscosity, volumetric stability, strength and others, for specific usage required properties, like heat permeability. The laboratory tests were performed on different mixtures of fly ash, boiler slag, cement and bentonite. Additionally, a commercial grout was investigated as a reference material. Index properties like the grain size distribution, the Enslin Neff water adsorption test, the Methylene blue test and the Atterberg limit tests were performed on dry row materials. On mixtures with water the volumetric stability and the viscosity were investigated. The compressive strength of hardened grout was measured after 28 days. The investigation shows that the water/dry mass ratio has a great influence to the mixture as well as to the hardened grout properties. Low addition of bentonite improves the stability of fresh mixture properties and the cement improves the strength of hardened fly ash grout. The boiler slag was found not to be suitable as a part of inert fill, because it is to coarse-grained and should be sieved before its use and it has not hydraulic properties.

Diplomska naloga obravnava vpliv lesnega pepela na mehanske, fizikalne, kemične in mineraloške lastnosti betona v svežem in strjenem stanju. Cementno vezivo smo nadomestili z lesnim pepelom v različnih količinah (10, 15 in 20 mas %). V okviru preiskav smo uporabili štiri različne pepele iz podjetij, kjer lesni pepel predstavlja odpadek iz njihove proizvodnje. Na začetku smo z reološkimi raziskavami preverili, kako pepel vpliva na lastnosti svežega betona. Nato smo na podlagi rezultatov tlačne, upogibne in cepilne trdnosti po 7 in 28 dneh ugotovili, kateri beton s pepelom daje najvišje trdnosti in kakšne so le te v primerjavi s trdnostmi referenčne sestave betona brez lesnega pepela. Z meritvami spreminjanja dolžin prizem s časom smo ugotavljali, kakšen vpliv ima lesni pepel na krčenje betona. Potem, ko so se deformacije zaradi krčenja umirile, smo prizme namočili v vodo za 42 dni in tedensko spremljali spremembo dolžin in mas prizem ter z merilnim instrumentom GrindoSonic določali dinamični modul elastičnosti. Na koncu smo na prizmah ponovno določili tlačno, upogibno in cepilno trdnost betonov in rezultate primerjali s tistimi pri starosti 28 dni. This graduation thesis deals with the impact of wood ash on the mechanical, physical, chemical and mineralogical properties of fresh and hardened concrete. Cement binder was replaced by wood ashes in various quantities (10, 15 and 20 wt. %). In the framework of the study, we used four different ashes from companies where wood ash represents a waste from their production. At the beginning we studied the impact of ashes on fresh concrete rheology. On the basis of the results of compressive, bending and splitting tests after 7 and 28 days, we determined which concrete with ash gives the highest strength and we compared the obtained results to the strengths obtained for the reference concrete without wood ash. By measurements of time dependent length change of the prisms we tried to find out the influence of the wood ash on the concrete shrinkage. After the shrinkage of the prisms had stabilised we put the prisms in water for 42 days. Every week we measured the changes in length and mass of the prisms and determined the dynamic modulus of elasticity, by using a measuring instrument GrindoSonic. At the end we once again determined compressive, flexural and splitting strengths of concrete mixtures and compared the obtained results to the strengths obtained at the age of concrete equal to 28 days.

V diplomski nalogi sem predstavil različne tipe kamnitih zidov in njihovo izdelavo. Predstavljeno je tudi kamnoseško orodje in vrste obdelanega kamna. Kamen je najstarejši gradbeni material za zidane konstrukcije. Iz njegove uporabe izhajajo vsa znanja o zidarskih tehnikah in zvezah. Glavni namen preiskav je ugotoviti, ali lahko zidarska zveza vpliva na tlačno trdnost kamnitega zidu. V ta namen smo zgradili troslojne kamnite zidove z dvema različnima zidarskima zvezama. Prvo polovico zidov smo pozidali z vezniško zidarsko zvezo, drugo polovico pa s smerniško zidarsko zvezo. Zidovi so bili pozidani z apneno malto, nato pa ometani z grobim in finim ometom. Opisane so preiskave za določanje tlačne in upogibne trdnosti za apneno malto in kamen. Opravili smo tudi preiskavi trdnosti stika med kamnom in malto ter trdnosti jedra zidu. Pri tlačni preiskavi zidov smo s globalne deformacije zidu. Teste smo opravili na dveh nizkih in dveh visokih zidovih, tako da smo lahko analizirali tudi vpliv višine preskušancev na tlačno trdnost zidovine. Ugotovili smo, da zidarska zveza ne vpliva na tlačno trdnost zidu, kar velja tako pri nizkih kot pri visokih zidovih. Tlačna trdnost visokih zidov je nekoliko nižja od tlačne trdnosti nizkih zidov. V nalogi sem naredil pregled modelov za izračun tlačne trdnosti ter analiziral različne pristope k izračunu tlačne trdnosti enoslojne in večslojne zidovine. ter jih s primerjal z eksperimentalnimi rezultati. Izkaže se, da je ob kombinaciji Mann-ovega in Bindinega modela možno napovedati tlačno trdnost večslojne kamnite zidovine In the thesis overview of different types of stone masonry and the construction techniques are presented. There are also presented stonecutting tools and different types of stone masonry units in dependence from the extend of dressing. Stone is the oldest building material for building masonry structures. Thus all the masonry techniques developed from the history of building with stone. The main purpose of the investigation was to determine the influence of masonry bond on the compressive strength of stone masonry. For this purpose three-leaf stone masonry walls with two types of masonry bond were built. The first type was built with through stones connecting outer leaves through the thickness of the wall. The second one was built without through stones but with staggering units along the edges. All the specimens were built with lime mortar and than plastered with coarse and fine plaster at the end. Results of determing compressive and flexural strength of mortar and stone and their bond are also presented. Inner core was also tested and its compressive and splitting tensile strength were determined. During compressive tests of masonry global deformations were measured. Compressive tests on masonry were performed on the specimens of the size of wallette and wall. The results of tests revealed that masonry bond do not have significant influence on obtained compressive strengths. Compressive strength was slightly lower for walls in comparisson to wallettes. Summarizing all experimental data and different analitical models for predicting compressive strength of multipleleaf masonry walls, it was showen that Mann's and Binda's models can be used for estimation of compressive strength for multiply-leaf masonry