Iskanje po katalogu digitalne knjižnice

Opis: This paper presents a study of PVC-P waterproofing membrane Specimens. The Specimens were taken from different segments of a flat roof after a service life of 11 years. The reason for analysing the condition of the Specimens was the apparent degradation of the waterproofing, which no longer guaranteed the watertightness of the roof. The analysis of the performance of the Specimens was based on the control of the mechanical properties, which were compared with the declared values. The mechanical properties of the degraded PVC-P waterproofing membranes with a polyester mesh backing, which are prescribed by the standards, do not usually deviate from the declared properties. This often poses a problem for liability and warranty claims due to the poor quality of the waterproofing membrane. There may be several causes of degradation of PVC-P. For this reason, in this paper, we present the possibility of controlling the properties of PVC-P waterproofing membranes using cyclic dynamic fatigue, microstructure analysis using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the cause of the deterioration of the PVC-P waterproofing membranes is often related to dehydrochlorination of the polymer. However, the deterioration of the mechanical properties of the PVC-P waterproofing membranes can be successfully demonstrated by cyclic dynamic fatigue.
Ključne besede: environmental impact of polymers, durability, polymer degradation
Objavljeno v DKUM: 13.03.2025; Ogledov: 0; Prenosov: 0
Celotno besedilo (14,34 MB)
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Opis: This paper describes the non-contact vibration monitoring of prestressed reinforced concrete railway sleepers. The monitoring was carried out using physical measuring equipment consisting of a seismograph and geophones, a robotic total station (RTS) and scanning laser Doppler vibrometry (SLDV) equipment. Measurements of the dynamic response of sleepers to the dynamic loading induced by the running of train sets provides data that give an insight into the actual state of the sleeper structure at the moment when it is most stressed. The main objective of the study was to identify the most appropriate form of monitoring to monitor events related to the occurrence of cracks in the rail sill, which can also be caused by the impact of vibration. As is well-known, monitoring the dynamic response of railway sleepers is very important for the sustainable management and maintenance of railway lines. The vibration analysis was carried out in the field on the Ormož–Ptuj section of the railway line, in Velika Nedelja and in the laboratory of the UM FGPA, where the vibration was simulated using a hydraulic kit with a static and pulsed force of 100 kN. Several cycles of measurement were carried out and the results were compared with the results of the field monitoring. The vibration parameters measured for the concrete sleepers are necessary to develop a realistic dynamic model of the railway line, which will be able to predict its response to impact loads and the possible occurrence of damage, as has recently been observed for concrete sleepers in several European Union countries.
Ključne besede: monitoring, measurement equipment, railway line, displacements, deformations
Objavljeno v DKUM: 12.03.2025; Ogledov: 0; Prenosov: 0
Celotno besedilo (6,49 MB)
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Opis: This study explores the potential of using basalt reinforced UHPC by incorporating simultaneously self-cleaning and self-luminescent features, paving the way for sustainable advancements in civil engineering. New green formulations of UHPC were developed by integrating supplementary cementitious materials and optimizing water to the binder ratio, followed by using basalt fibers to enhance strength and ductility. The fabricated samples with high particle-packing density exhibit sufficient workability and compressive strength up to 136 MPa, and, when incorporating basalt fibers, a notable reduction in brittleness. The inner microstructure of basalt fibers was observed to be smooth, homogeneously distributed, and well adhered to the UHPC matrix. To ensure the desired long-lasting visual appearance of decorative UHPC and reduce future maintenance costs, a time-effective strategy for creating a light-emitting biomimetic surface design was introduced. The samples exhibit high surface roughness, characterized by micro to nano-scale voids, displaying superhydrophobicity with contact angles reaching up to 155.45°. This is accompanied by roll-off angles decreasing to 7.1°, highlighting their self-cleaning features. The self-luminescence feature showcased intense initial light emission, offering a potential energy-efficient nighttime lighting solutio
Ključne besede: UHPC, basalt fibers, mechanical properties, morphology, superhydrophobic, self-luminescence
Objavljeno v DKUM: 29.01.2024; Ogledov: 368; Prenosov: 446
Celotno besedilo (14,47 MB)
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Opis: Ena izmed ključnih lastnosti pri gradnji stavb je toplotna izolativnost stavb. V sodobnem gradbeništvu predstavlja velik izziv zmanjšanje porabe energije, ki nastaja pri izdelavi umetnih izolacijskih materialov. Na vzorcih naravne toplotne izolacije iz lesenih vlaken, iz konoplje, plute ter ovčje volne smo z metodami določitve tlačne trdnosti pri 10% deformaciji, določitvi kontaktnega kota ter mikroskopiranjem ugotavljali, kako staranje vpliva na toplotno izolacijo. Prišli smo do ugotovitev, da so se tlačne trdnosti vsem izolacijskim materialom po staranju zmanjšale, ter da se je zmanjšal tudi kontaktni kot naravnih toplotnih izolacij. Mikroskopiranje je pokazalo, da je po staranju prišlo do razplastitve plasti naravnih toplotnih izolacij.
Ključne besede: izolacijski materiali, konoplja, pluta, les, ovčja volna
Objavljeno v DKUM: 04.10.2022; Ogledov: 811; Prenosov: 44
Celotno besedilo (5,11 MB)

Opis: Osnovni namen projektne naloge je ugotoviti, da obstaja veliko vrst izolacij; nekatere so zelo drage; njihova cena je pretirana. Na trgu se prodajajo tudi cenejši, vendar je njihova največja težava ta, da so zelo nezdravi za človeško življenje. Nekatere izolacije povzročajo težave s kožo, nekatere pa celo povzročajo raka kože. Ugotovili smo novo formulo za boljši, bolj ekonomičen, popolnoma zdrav in naraven način izdelave nove vrste hišne izolacije. Naš izdelek vsebuje snov zeolit kot snov z veliko absorpcijsko sposobnost. Gre za naravni material z velikim spektrom uporabe.
Ključne besede: zeolit, izolacija, izolacijski materiali, zvočna izolacija, toplotna izolacija.
Objavljeno v DKUM: 07.09.2021; Ogledov: 1138; Prenosov: 80
Celotno besedilo (2,21 MB)