71. Influence of curing / drying methods including microwave heating on alkali activation of waste casting coresBarbara Horvat, Vilma Ducman, 2021, published scientific conference contribution Abstract: Within previous investigation alkali activation of waste casting cores at room temperature did not give promising results, i.e. when the precursor was gently ground and sieved below 600 %m the alkali activated material fell apart at demolding, and when the precursor was ground below 90 %m, the alkali activated material did not solidify in more than 2 years. , Therefore different drying/curing methods were applied to enhance the reaction. Waste casting cores were prepared in two granulations (sieved below 600 %m and below 90 %m), activated with Na -water glass and 10 M NaOH, cured at different temperatures (70 °C and room temperature), and subsequently cured/dried at three different conditions: room temperature, 110 °C, and irradiated with microwaves. The highest compressive strength, 25 MPa, was gained with subsequent curing/drying at 110 °C. The lowest density, 0.5 kg/l, with compressive strength above 3 MPa, was achieved with subsequent curing/drying with microwaves .
Keywords: waste casting cores, alkali activation, curing, drying, microwaves, mechanical strength
Published in DiRROS: 22.01.2024; Views: 227; Downloads: 118
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72. Comprehensive permanent remote monitoring system of a multi-span highway bridgeAndrej Anžlin, Uroš Bohinc, Doron Hekič, Maja Kreslin, Jan Kalin, Aleš Žnidarič, 2021, published scientific conference contribution Abstract: As part of the reconstruction of a multi-span viaduct on a Slovenian highway, a permanent remote monitoring system with over 200 sensors was established. Several parameters are monitored on different parts of the viaduct by means of temperature sensors, accelerometers, strain gauges, long-gauge deformation and Fibre Bragg Grating (FBG) sensors. In this way strains, frequencies and temperatures on external prestressed beam cables, carbon fibre rebarsused for the flexural strengthening of a deck overhang, pier caps and prestressed beams are measured and stored into the on-site central data acquisition system. This paper presents architecture of the permanent bridge monitoring system and preliminary results of the measurements.
Keywords: permanent monitoring, structural health monitoring, bridge WIM, sensors, viaduct
Published in DiRROS: 22.01.2024; Views: 297; Downloads: 129
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75. Manual for use of Al-containing residues in low-carbon mineral bindersSabina Dolenec, Katja Malovrh Rebec, Anja Lešek, Katarina Šter, Lea Žibret, Gorazd Žibret, Klemen Teran, Emil Pučko, Ildikó Merta, Bojan Poletanovic, Elena Yaneva, Peter Kesserű, Ildikó Kovács, Bence Kószó, Alexandra Németh, Richard Laucournet, Mustafa Hadžalić, Emilija Fidanchevski, Biljana Angjusheva, Vojo Jovanov, Miloš Nenadović, Snežana B. Nenadović, Ivana Vukanac, Liljana Kraljević, Mojca Loncnar, Andrej Ipavec, 2020, dictionary, encyclopaedia, lexicon, manual, atlas, map Abstract: Današnje družbe si ni več mogoče predstavljati brez sodobne infrastrukture, ki temelji na uporabi različnih materialov ter zahteva veliko porabo energije. Vzporedno s proizvodnjo materialov, nastajajo ogromne količine različnih industrijskih in rudarskih ostankov (odpadki/stranski proizvodi), ki jih trenutno ne izkoriščamo, sama odlagališča pa so premalo raziskana. Cilj Evropske unije (EU) je povečati učinkovito rabo virov in ponudbo sekundarnih surovin z recikliranjem, popisom odpadkov iz rudarskih in drugih industrijskih dejavnosti ter njihova ponovna uporaba. Veliko industrijskih in rudarskih odpadkov je obogatenih z aluminijem (Al), zato lahko nadomeščajo naravne vire Al v mineralnih veznih, vendar njihova uporaba zahteva obsežno poznavanje njihovih kemijskih, mineraloških, radioloških in fizikalnih lastnosti. Priročnik, ki so ga pripravili partnerji projekta RIS-ALiCE obravnava zakonodajne vidike, ki urejajo uporabo sekundarnih surovin v gradbenih proizvodih, opis najpogostejših industrijskih in rudarskih ostankov, ki vsebujejo Al (nahajališča boksitov, rdeče blato, jeklarske žlindre, pepeli iz različnih industrij, itd.), potencial njihove ponovne uporabe in njihov ekonomski vidik, potencialne zahteve/ovire za uporabo sekundarnih surovin v cementni industriji in opis belitno-sulfoaluminatnih cementov, ki so obetavna rešitev za izvajanje krožnega gospodarstva z uporabo velikih količin odloženih industrijskih in rudarskih odpadkov, bogatih z Al.
Keywords: gradbeni proizvodi, ponovna uporaba, ekonomski vidik, industrija cementa, krožno gospodarstvo, industrijski odpadki, zakonodaja, elektronske knjige
Published in DiRROS: 22.01.2024; Views: 229; Downloads: 93
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76. Use of steel slag for the synthesis of belite-sulfoaluminate clinkerLea Žibret, Martina Cvetković, Maruša Mrak, Mojca Loncnar, Andrej Ipavec, Sabina Dolenec, 2020, published scientific conference contribution Abstract: Belite-sulfoaluminate (BCSA) cements are low-carbon mineral binders, which require low energy consumption and allow the incorporation of various secondary raw materials in the clinker raw meal. In this study two types of unprocessed steel slags, coming from stainless steel production, were incorporated in the BCSA clinkers. The clinker phase composition, clinker reactivity, and the compressive strength of the cement were studied to evaluate the possible use of the slag in BCSA clinkers. The cement clinkers were synthesized by using natural raw materials, white titanogypsum, mill scale, as well as two different steel slags: (i) EAF S slag, which is a by-product of melting the recycled steel scrap in an electric arc furnace, and (ii) la dle slag as a by-product of the processes of secondary metallurgy, in various quantities. Raw mixtures with two different targeted phase compositions varying in belite, calcium sulfoaluminate and ferrite phases were sintered at 1250 °C. Clinker phases were determined by Rietveld quantitative phase analysis, while their distribution, morphology and incorporation of foreign ions in the phases were studied by SEM/EDS analysis. The clinker reactivity was determined by isothermal calorimetry. BCSA cements were prepared by adding titanogypsum. The compressive strength of the cement pastes was determined after 7 days of hydration. The presence of a predicted major clinker phases was confirmed by Rietveld analysis, however periclase was also detected. Microscopy revealed subhedral grains of belite and euhedral grains of calcium sulfoaluminate phases, while ferrite occurred as an interstitial phase. The results showed differences in the microstructure and reactivity of the clinker and cement, which can be attributed to varying amounts of ettringite due to different slag types
Keywords: belite-sulfoaluminate cement, cement clinker, steel slags, clinker microstructure, cement reactivity
Published in DiRROS: 19.01.2024; Views: 215; Downloads: 88
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77. Appropriate sound insulation of facades as a measure to ensure acceptable acoustic comfort in residential buildingsMihael Ramšak, 2020, published scientific conference contribution Abstract: Wherever possible, the environment with residential buildings should be protected from the effects of noise sources by environmental noise reduction measures. If such measures cannot reduce the noise level in the environment to an acceptable level, acceptable acoustic comfort in the residential buildings shall be ensured by adequate sound insulation of the facades, which is the main topic of this paper. The paper outlines some of the criteria for providing good acoustic comfort in the residential buildings, on the basis of which the conditions and necessary measures for providing sufficient sound insulation of the facade elements are discussed. Since, in addition to the noise from the environment, the acoustic comfort in apartments is also affected by the noise from adjacent apartments in the building, the link between the sound insulation performance of facades and audibility of the speech noise form adjacent apartments is also discussed.
Keywords: acoustic comfort, traffic noise, soun levels, sound insulation
Published in DiRROS: 19.01.2024; Views: 235; Downloads: 79
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78. Extending BIM for air quality monitoringMichael Nicolas Mrissa, Jan Vcelak, László Hajdu, Balázs Dávid, Miklós Ferenz Krész, Jakub Michal Sandak, Anna Malgorzata Sandak, Rok Kanduti, Monika Varkonji, Anja Jutraž, Katja Malovrh Rebec, 2020, published scientific conference contribution Abstract: As we spend more than 90% of our time inside buildings, indoor environmental quality is a major concern for healthy living. Recent studies show that almost 80% of people in European countries and the United States suffer from SBS (Sick Building Syndrome), which affects physical health, productivity and psychological well-being. In this context, environmental quality monitoring provides stakeholders with crucial information about indoor living conditions, thus facilitating building management along its lifecycle, from design, construction and commissioning to usage, maintenance and end-of-life. However, currently available modelling tools for building management remain limited to static models and lack integration capacities to efficiently exploit environmental quality monitoring data. In order to overcome these limitations, we designed and implemented a generic software architecture that relies on accessible Building Information Model (BIM) attributes to add a dynamic layer that integrates environmental quality data coming from deployed sensors. Merging sensor data with BIM allows creation of a digital twin for the monitored building where live information about environmental quality enables evaluation through numerical simulation. Our solution allows accessing and displaying live sensor data, thus providing advanced functionality to the end-user and other systems in the building. In order to preserve genericity and separation of concerns, our solution stores sensor data in a separate database available through an application programming interface (API), which decouples BIM models from sensor data. Our proof-of-concept experiments were conducted with a cultural heritage building located in Bled, Slovenia. We demonstrated that it is possible to display live information regarding environmental quality (temperature, relative humidity, CO2, particle matter, light) using Revit as an example, thus enabling end-users to follow the conditions of their living environment and take appropriate measures to improve its quality
Keywords: Building Information Model, internet of things, environmental quality monitoring, healthy living
Published in DiRROS: 19.01.2024; Views: 210; Downloads: 92
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79. Measurement of the chloride resistance of environmentally friendly and durable concreteAlisa Machner, Marie Helene Bjørndal, Aljoša Šajna, Lucija Hanžič, Yushan Gu, Benoit Bary, Klaartje De Weerdt, 2020, published scientific conference contribution Abstract: The increasing demand for concrete and thereby Portland cement, creates the need for novel low-clinker Portland composite cements. Concretes prepared with such novel composite cements need to show similar or even improved durability compared to concrete prepared with commonly used Portland composite cements. This study represents a part of the EnDurCrete project that focuses on the durability of concrete produced with novel low-clinker cements, containing high-value industrial by-products. More specifically, we investigated the chloride ingress resistance of such concrete. Concrete cylinders were submitted to chloride ingress by bulk diffusion. The chloride ingress resistance was investigated on concrete samples by %XRF scanning and chloride titration. In addition, the chloride binding capacity of these novel binders was investigated on paste samples by determining chloride binding isotherms for both binders. In the next step of the project, these experimental results will be matched with an advanced model, which is being developed within the project. By combining modelling with experimental verification, we aim to reach a better understanding of the fundamental chloride ingress mechanisms acting on novel types of concrete. The overall goal of the work is to produce a concrete with lower cost, lower environmental footprint and with verified similar or improved durability.
Keywords: chloride ingress, durability, novel binders, Low C02, sustainability, concrete
Published in DiRROS: 19.01.2024; Views: 234; Downloads: 101
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80. Experimental and numerical investigation of restrained shrinkage of concreteLucija Hanžič, Jurij Karlovšek, Tomaž Hozjan, Sabina Huč, Zhongyu Xu, Igor Planinc, Johnny Ching Ming Ho, 2020, published scientific conference contribution Abstract: To promote the understanding of shrinkage related behaviour of concrete used for tunnel linings the experimental and theoretical investigation including numerical and analytical approach was performed on ring-shaped specimens. Overall one analytical (an.) and two numerical models, namely (i) and (ii) were also developed. Models (an.) and (i) considered the restraining steel ring to be rigid, thus not exhibiting any deformation. Numerical model (ii) considered the steel ring to be deformable. The experimental set-up consisted of a large concrete ring with an inner diameter of 120 cm, an outer diameter of 160cm and 20 cm in height. The restraining steel ring was 5.5 cm thick. Two concrete rings were made, namely R1 with a low compressive strength of ~26MPa and the other, R2, with medium compressive strength of ~40 MPa. The strain was measured in the hoop direction on the inner circumference of the steel ring and on the outer circumference of the concrete ring. Concrete rings were subjected to circumferential drying. Numerical model (ii) predicted critical time to the formation of the first crack to be between 13 and 14 days. The experimentally determined critical time is found to be 11 to 13 days with cracks gradually opening over several days. This was indicated by changes in measured concrete and steel strain. Modelled concrete strain just before cracking was between -20 and -30 % 10-6 m m-1 however, measured concrete strain was ~150 % 10-6 m m-1. Modelled steel strain was between -30 and -40 % 10-6 m m-1 while measured steel strain was between -10 and 20 % 10-6 m m-1. These discrepancies, in particular the positive steel strain obtained in experiments, require further investigation and improvements of the experimental set-up.
Keywords: concrete, tunnel lining, restrained shrinkage, Reissner beam theory, modelling
Published in DiRROS: 19.01.2024; Views: 233; Downloads: 92
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