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Povzetek: 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.
Ključne besede: polymer modified bitumen, recovered bitumen, laboratory ageing, dynamic shear rheometer, multiple stress creep recovery test
Objavljeno v DiRROS: 28.02.2024; Ogledov: 146; Prenosov: 97
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Povzetek: Bridges and tunnels, crucial elements of the railway infrastructure, are exposed to various types of deterioration processes. Their condition is a subject of monitoring, as it is important to collect as much as possible information in every life cycle phase to reliably predict their future performance. An enormous quantity of monitoring data is generated during the whole life cycle of these assets. EU funded Shift2Rail research project Assets4Rail which is focusing on measuring, monitoring, and data handling for railway assets, as data management is as important as their generation. This paper presents the major outcomes of the Assets4Rail project and its application to infrastructure projects.
Ključne besede: monitoring, information management, BIM, information management, bridge, tunnel, Assets4Rail
Objavljeno v DiRROS: 23.02.2024; Ogledov: 169; Prenosov: 96
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Povzetek: Road infrastructure asset management is rapidly transforming into a digital environment where data accessibility, effective integration and collaboration and accessibility from different sources and assets are key. However, current asset management processes are not yet fully integrated or linked, and there are incompatibilities between various systems and platforms that limit the ability to integrate asset management with BIM. The CoDEC project has sought to understand the current status of information management for assets, including inventory, condition and new data sources such as sensors and scanning systems, to identify the challenges and needs for linking and integrating different data sets to support effective asset management. As a result, CoDEC has developed a data dictionary framework to help link/integrate static and dynamic data for the "key" infrastructure assets (road pavements, bridges, tunnels). This will enable BIM and Asset Management Systems (AMS) to exchange data and help optimise and integrate data management across systems and throughout the different asset lifecycle phases, from build to operation. This work will be followed up with three pilot projects to demonstrate the feasibility of integrating asset data from various sources through linked data/semantic web technology to build the connection between AMS and BIM platforms.
Ključne besede: CoDEC, asset managemen, asset data, data dictionary, linked data, BIM, ontology
Objavljeno v DiRROS: 22.02.2024; Ogledov: 172; Prenosov: 65
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Povzetek: 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.
Ključne besede: bitumen, polietilen, reologija, medlaboratorijska primerjava
Objavljeno v DiRROS: 20.02.2024; Ogledov: 132; Prenosov: 60
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Povzetek: The structural and physio-chemical properties of biochar are crucial to determining biochar’s quality and the adequate application. Specifically, the large porosity of biochar has been known as a favorable feature, especially for environmental remediation. In this regard, physical and chemical modifications have been used to improve biochar’s porosity which requires high-energy consumption and involves chemical agents. The objective of this study was to prepare biochar with developed porosity using mild treatments. Arundo donax and olive stone were demineralized by a water-washing method. Treated and non-treated biomasses were pyrolyzed, and part of the derived samples was subjected to wet ball milling. Samples were characterized with proximate, Fourier transform infrared, particle size, and physisorption analyses. The effect of demineralization depended on the biomass type, as ash reduction only influenced Arundo donax-derived biochar, which was attributed to the difference in initial ash content that was relatively low for olive stone. The carbonization yield decreased by 46% for the Arundo donax biomass after demineralization. Moreover, demineralization expanded the surface area and total pore volume of the Arundo donax biochar. The ball milling was effective in producing micro-sized biochar particles with a mean size ranging between 30 ± 2 µm and 42 ± 2 µm and between 13 ± 1 µm and 22 ± 2 µm for Arundo donax and olive stone without and with demineralization, respectively. Ball milling increased the surface area of non-demineralized Arundo donax by 47% and demineralized Arundo donax by 124%. Additionally, ball milling increased the surface area of non-demineralized olive stone by 65% and demineralized olive stone by 62%.
Ključne besede: biomass, carbonisation, porosity
Objavljeno v DiRROS: 13.02.2024; Ogledov: 134; Prenosov: 75
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