Repository of the Institute for Material Testing (RIMS)
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Water permeability properties of concrete with crumb rubber
Get PDFThe paper shows the possibility of using crumb rubber in the fine aggregate fraction. Crumb rubber with the grain size of 0-1 mm was used, which was obtained in the process of recycling car tires. Concrete mixes with natural aggregate were designed in which the 0/4 mm fraction was volume replaced with crumb rubber in amounts of 2.5%, 5% and 7.5%. All concretes are made with the same component materials with a water-cement ratio of 0.45. Water absorption tests, as well as water penetration depth under pressure, were performed. After the tests, it was found that increasing the rubber content results in concrete with the lower depth of water penetration under pressure and lower water absorption
State and perspectives of sustainable production of traditional silicate ceramics
Get PDFThe traditional ceramics industry uses large amounts of primary mineral raw materials. Improvements in the production of building materials based on non-metallic minerals can contribute to sustainable development in many ways, such as saving natural resources, using waste materials, reducing energy consumption, decreasing emissions hazardous to the health and the environment, particularly carbon dioxide, and reclamation of mines after exploitation of raw materials, etc. This paper describes the state of application of mineral raw materials and waste in the traditional ceramics industry with a perspective on future challenges. Intensified research is needed to complement the laboratory data and re-scale to the industrial-sized products while improving communication between both sectors
Determination of the effects of the rebar-cement bond parameters variation in UHPFRC using FA and ANN
Get PDFThe experimental study included the design and production of ultra-high-performance steel fiber-reinforced concrete (UHPFRC). The physical and mechanical properties of UHPFRC were investigated in a laboratory setting. To investigate the properties of UHPFR concrete, three types of concrete and over 70 samples were used. Following that, samples were created to test the anchors' load-bearing performance. Six concrete slabs with a total of 108 pre-installed anchor samples and six concrete slabs with 108 post-installed chemical anchor samples were created. The analysis of the test findings comprised all individual results as well as the definition of the relationship between the anchor's tensile load capacity and other parameters. To accurately determine the individual influence of the investigated factors as well as their combined impact, a factorial experiment, and artificial neural networks were used in addition to normal statistical numerical studies. It was determined that both approaches offer advantages. The results obtained show matches in certain parts. Due to the way data is processed in different ways, there are also significant differences between them
Assessment of Borač-Kotlenik magmatic massif rock mass technical properties as potential source for optimal development of regional road infrastructure based on local stone materials
No full textThe Borač-Kotlenik magmatic massif in central Serbia is mainly made up of effusive and pyroclastic rocks, formed in three main phases of volcanic activity: 1. dacite and ande-site, 2. quartz-latite and dacite, and 3. basaltoid rocks.
Rock mass samples from this magmatic massif have been examined and mined in numerous localities during the XX century for purposes of building and reconstruction works of local and regional road networks. The examination process continues today for purposes of ‘Morava corridor’ highway building and its demand for the local stone material of the specified quality.
The results of rock mass technical properties' tests have shown that its quality for road building purposes depends significantly on petrologic type, soundness, and hydrother-mal alteration type. Oxidation alteration types can cause a significant decrease in compressive strength, an increase in porosity and water absorption, especially as oxidative chem-ical processes cause increased susceptibility to weathering, thus making the rock mass unusable in road construction profile layers above the embankment.
Testing results demonstrate that effusive volcanic rocks of the Borač-Kotlenik magmatic massif generally can be used in the road building process. For this purpose, it is necessary to select the conformable rock mass zones at each locality, where hydrothermal alteration and weathering products are absent in order to obtain the best available stone material of volcanic origin
Low cyclic fatigue curves of steel
No full textTo describe the behavior of a steel structure exposed to low-cycle fatigue (LCF), characteristic curves constructed on the basis of data obtained from LCF testing of steel are used: Cyclic stress-deformation curve (CSDC) and Basic curve of low-cycle fatigue (BCLCF). In order to ensure reliability and consistency of results from different laboratories, it is necessary to collect all test data that is in accordance with a number of key points of the standard ISO 12106:2017(E) and/or ASTM E 606-04. The tests yield huge amounts of data, graphically shown in Figure 1a, for only one level of regulated deformation (the recommendation is 10 levels and at least 3 levels are required), which need to be filtered and from that pile to extract what we need to construct the characteristic curves of the low-cycle fatigue, Figure 1b and 1c
Modelovanja transporta toplote u višeslojnim strukturama u nestacinarnom režimu korišćenjem Grin-ove funkcije i ekvivalnentnih električnih RC kola
No full textPredstavljena je analiza transporta toplote kroz višeslojne građevinske pregrade u nestacionarnom slučaju u vremenskom domenu. Razamatrani su pristupi bazirani na Grin-ovim funkcijama i konvoluciji kao i modelovanje nestacinarnih termičkih procesa korišćenjem ekvivlaentnog RC kola. Pokazano je da je sa praktičnog stanovišta, pri analizi termalnih gubitaka u građevinskim objektima, metod baziran na Grin-ovim funkcijama i konvolucionom integralu u vremenskom domenu pogodoniji za određivanje fluksa toplotnih gubitaka kroz višeslojne pregrade u slučajevima kada su poznate vemenski promenljive temperature vazduha sa spoljašne i unutrašnje strane posmatrane strukture, dok je modelovanje bazirano na ekvivalentnom električnom RC kolu pogodnije u slučajevima kada su poznate vremenski zavisna spoljašnja temperatura vazduha i snaga unutrašnjih grejnih tela. U modelu baziranom na RC kolu moguće je uzeti u obzir i toplotne gubitke kroz pod kao i toplotni kapacitet prostorije, što je u slučaju pristupa baziranog na Grin-ovim funkcijama u vremenkom domenu znatno složenije. Na osnovu razvijenog numeričkog RC modela dobijene su toplotne dinamičke karakteristike posmatranog višeslojnog zida u vidu vremenskih konstanti za različite delove konstrukcije
Primena georadara pri proceni stanja prethodno napregnutnih mostova
No full textProcena i održavanje armiranih i prednapregnutih betonskih mostova od ključnog su značaja za očuvanje integriteta i produženje njihovog veka trajanja. Georadar (GPR) postao je neophodna nedestruktivna metoda za evaluaciju ključnih parametara pri proceni stanja, poput rasporeda armature, geometrije i prisustva defekata kao što su korozija ili delaminacija kao i za lociranje kablova za prednaprezanje (određivanje položaja i podužnih šipki armature i kablova). U ovom radu pokazana je primena georadara (Proceq GP8800), profometra (Proceq 650 AI) i ultrazvučni tomograf (Proceq Pundit PD8000) na primerima projekata prednapregnutih konstrukcija železničkog mosta (Želežnička stanica Novi Beograd) i drumskog mosta (granični prelaz Karakaj - Mali Zvornik). Nedavne studije naglašavaju važnost primene antena visoke frekvencije radi poboljšanja detekcije anomalija, posebno u identifikaciji oštećenja uzrokovanih korozijom armature delova nosive konstrukcije mosta. Simulacije su pokazale da izbor optimalne radne frekvencije značajno utiče na tačnost detekcije. Pored toga, starenje prednapregnutih betonskih mostova suočava se sa izazovima poput pojave prslina, korozije, delaminacije i smanjenja krutosti, što zahteva aktivno praćenje i održavanje kako bi se usporila degradacija nosive konstrukcije. Studije slučaja ističu prednosti i ograničenja različitih metoda inspekcije, naglašavajući njihov značaj u očuvanju bezbednosti, smanjenju troškova i ekološkog uticaja, dok se istovremeno obezbeđuje trajnost ovih ključnih infrastrukturnih objekata
Production of cement clinker based on alternative raw materials
No full textOrganizator: Universidad Politécnica de Madri
Increase of frost resistance of clay masonry units with construction demolition waste addition: A case study
No full textThis paper fits into Goal 12 of the United Nation Sustainable Development Goals and promotes the green agenda and circular economy demands. The granulated construction and demolition waste (CDW) was added into the raw clay material and laboratory masonry clay elements (hollow block and brick) were extruded, dried and fired. The XRD, DTA, dilatometry, pore size distribution and sieve test were used for material characterization. The influence of CDW addition on plasticity, drying sensitivity as well as green and fired products characteristics and frost resistance of masonry clay units was investigated. The standard EN 772-22 and ASTM C 1167-03 were used respectively as a direct and indirect test method for the evaluation of frost resistance. Results are indicating that the addition of cheap CWD, which is available in large quantities and until now was not used in ceramic masonry industry, can affectively adapt the pore size distribution of the final product and lead to the excellent frost resistance properties at lower firing temperatures. Registered decrease of mechanical properties has not compromised the application of this products in load bearing walls since the compressive strengths were still larger than the limiting one for products intended use.(ModTech 2024) Held in June 24-27.2024, Kuala Lumpur, Malaysi