1. Quality checking of polymer modified bitumens in SloveniaMarjan Tušar, Lidija Ržek, Mojca Ravnikar Turk, 2021, published scientific conference contribution Abstract: For many years the properties of bitumen have been determined based on mechanical tests as needle penetration, Ring&Ball and Fraass fracture temperature. For elastomer (styrene-butadiene-styrene) polymer modified bitumens these tests are not sufficient to show the important differences in bitumens. Elastic recovery and cohesion provide better insight, but rheological properties cannot be adequately described with conventional test. The requirements of the polymer modified bitumens (PmB) in Europe were defined in EN14023 in 2010 [1]. Since then several new tests were introduced in the research field and their procedures improved. In the European Standards Committee (CEN) TC 336, there is on-going work to develop performance related specifications. New laboratory test methods from American standards were adapted and transformed into EN standards (bitumen laboratory aging methods and rheological tests). These test methods are not yet employed in the cur-rent PmB European standard, however, the draft prEN 14023, April 2020 [2] suggests these new tests. In the recent years at ZAG Laboratory for asphalts and bitumen-based products long-term aging of bitumen by pressure aging vessel (PAV) and rheological tests were introduced. Traditional bitumen test methods are performed together with new rheological testse.g. Dynamic Shear Rheometer (DSR) testing, to characterize complex modulus and phase angle, and Multiple Stress Creep Recovery Test (MSCRT) in order to develop a preliminary data base on PmB’s, which are frequently used in Slovenia. The paper presents the current requirements for PmB’s in Slovenia and test results on PmB 45/80-65, original, laboratory aged and extracted from produced asphalt mixtures.
Keywords: polymer modified bitumen, recovered bitumen, laboratory ageing, dynamic shear rheometer, multiple stress creep recovery test
Published in DiRROS: 28.02.2024; Views: 113; Downloads: 73
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2. Volumetric view on asphalt mixtureMarjan Tušar, Mojca Ravnikar Turk, Lidija Ržek, 2023, published scientific conference contribution Abstract: An asphalt layer consists of stone aggregates, binder and air voids. The content of air voids (Vmin and Vmax), the voids filled with bitumen (VFBmin and VFBmax), the content of air voids in stone aggregates (VMAmin and VMAmax) and volume content of bitumen (VBmin) should be determined for each type of asphalt mixture. The volumetric properties of asphalt layer listed above are important parameters for assessing the properties of asphalt and are usually first presented in the requirements for produced asphalt mixtures and built in asphalt layers. Visualization of volumetric properties is important for understanding the composition of the produced asphalt mixture. The most appropriate is a triangular representation of the volumetric requirements for three main components of asphalt layer (stone, bitumen and air).
Keywords: volumetric representation, asphalt mixture, void content, voids in aggregate
Published in DiRROS: 22.02.2024; Views: 120; Downloads: 56
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3. Rheological behaviors of waste polyethylene modified asphalt binder : Statistical analysis of interlaboratory testing resultsDi Wang, Andrea Baliello, Gustavo Pinheiro, Lily D. Poulikakos, Marjan Tušar, Kamilla Vasconcelos, Muhammad Rafiq Kakar, Laurent Porot, Emiliano Pasquini, Gaspare Giancontieri, Chiara Riccardi, Marco Pasetto, Davide Lo Presti, Augusto Cannone Falchetto, 2023, original scientific article Abstract: This article investigated the effect of waste polyethylene (PE) on the modified asphalt binders’ rheological behavior from a statistical point of view. The interlaboratory testing results from the RILEM Technical Committee 279 Valorization of Waste and Secondary Materials for Roads Task Group 1 were used for this purpose. First, an unaged 70/100 penetration graded neat binder was selected as the reference material. Next, a single 5 % content of waste PE additives (PE-pellets and PE-shreds) was mixed with a 95 % neat binder to prepare two PE modified binders. Then, dynamic shear rheometer–based temperature-frequency sweep tests were performed over a wide range of temperatures and frequencies to evaluate the rheological properties of these three binders. Different rheological behaviors were observed in the isochronal plots at high temperatures. Based on a reproducibility precision requirement proposed for phase angle, 28°C was set as the transition temperature across the rheological behaviors. Next, according to the three rheological behaviors defined in a previous study by the authors, statistical analysis was introduced to identify sensitive rheological parameters and determine the thresholds. Results indicate that the phase angle measured above 28°C and 1.59 Hz can be used as a sensitive parameter to discriminate the three rheological behaviors of PE modified binders. The thresholds among different behaviors were also calculated as an example for phase angle measured at the highest common testing temperature of 70°C. Additional experimental evaluations on more types of PE modified binders, especially at intermediate and high temperatures, are recommended to better understand their influence on the rheological behavior of PE modified binders.
Keywords: bitumen, polietilen, reologija, medlaboratorijska primerjava
Published in DiRROS: 20.02.2024; Views: 113; Downloads: 49
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4. Rejuvenator obtained by pyrolysis of waste tires for use in asphalt mixtures with added reclaimed asphaltLidija Ržek, Mojca Ravnikar Turk, Marjan Tušar, 2022, independent scientific component part or a chapter in a monograph Abstract: Although in recent years, big progress has been made in the field of recovering waste tires, they still represent an unwanted waste and their production is constantly increasing. We can use waste tires as a raw material for a new product. In our study, multiple liquid products were produced by pyrolysis of waste tires. After extensive testing of their properties, we selected the most suitable pyrolytic product for the purpose of rejuvenation. Rejuvenators are designed to soften the old, brittle and stiff aged bitumen in reclaimed asphalt. Bitumen with its viscoelastic characteristics is the most important component of asphalt and dictates its behaviour. Commonly bitumen, after adding rejuvenator, becomes less viscous, more ductile and its coating properties are restored. By using a pyrolytic rejuvenator, the proportion of reclaimed asphalt added to the asphalt mixture was increased. The reuse of reclaimed asphalt and waste tires means a reduction in waste material and is therefore important for the preservation of the environment and sustainable development.
Keywords: pyrolyse, rejuvenator, bitumen, reclaimed asphalt, waste tires
Published in DiRROS: 31.01.2024; Views: 149; Downloads: 63
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5. Karakterizacija s polimeri modificiranih bitumnov z reološkimi preiskavamiMojca Ravnikar Turk, Lidija Ržek, Marjan Tušar, 2021, original scientific article Abstract: Cestne povezave morajo biti odporne proti podnebnim in prometnim obremenitvam, intervali vzdrževanja asfaltnih vozišč pa čim daljši. Zato naftna industrija razvija vedno bolj odporne bitumne za cestogradnjo, hkrati pa se uveljavljajo nove preiskave, s katerimi lahko obnašanje bitumnom celovito ovrednotimo. Za karakterizacijo s polimeri modificiranih bitumnov (PmB) osnovne preiskave trdote in zmehčišča, ki se že dolga leta uporabljajo, ne zadoščajo. Zato se določajo tudi reološke karakteristike. Za karakterizacijo se uporablja dinamični strižni reometer, s katerim v kontroliranih pogojih napetosti in deformacij na majhnih vzorcih bitumna določamo viskoelastične in plastične lastnosti vzorcev bitumna. V prispevku so prikazani rezultati osnovnih in reoloških preiskav s polimeri modificiranih bitumnov različnih trdnostnih razredov, ki se uporabljajo v slovenskem prostoru.
Keywords: s polimeri modificiran bitumen, reologija, DSR, MSCRT
Published in DiRROS: 04.12.2023; Views: 202; Downloads: 90
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6. A triangular representation of the volumetric properties of asphalt mixturesMarjan Tušar, Mojca Ravnikar Turk, Lidija Ržek, 2022, original scientific article Keywords: triangular representation, asphalt mixture, volumetric properties, void content, bitumen content, voids in aggregate
Published in DiRROS: 10.03.2022; Views: 599; Downloads: 388
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