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    Long-Term Monitoring of the Behavior of Modified Bitumens of RC Type
    (MDPI, 2024-12-17) Varaus, Michal; Dašek, Ondřej; Hýzl, Petr; Stehlík, Dušan; Spiegl, Markus
    This paper discusses the properties of OMV Starfalt® PmB 45/80 RC bituminous binder developed by the Austrian oil company OMV Downstream GmbH (OMV, Vienna, Austria), intended to be used for the recycling of reclaimed asphalt mixtures (RAP). The binder is characterized by various adjusted properties like higher needle penetration, higher softening point and higher elastic recovery (close to 95–100%), with the aim to compensate for the properties of the aged binder contained in the reclaimed asphalt. Three experimental sections were laid in the Czech Republic. Monitoring was performed on these sections (cores were taken after 0, 6, 12, 24, 44 and 93 months) with a consecutive analysis of the properties of the used binder—the binder was extracted from the cores and tested for penetration, softening point, critical temperature at bending beam rheometer (BBR), complex modulus and phase angle using a dynamic shear rheometer (DSR). The previously described binder was used during the construction of trial sections in the villages Domasov and Lednice and near the city Opava. In the first case, a surface course mixture of asphalt concrete type (AC surf 11+) contained 18% of RAP, whereas in the second and third case, a binder course mixture of asphalt concrete type (AC bin 22 S) comprised 23% and 39% of RAP, respectively. After approx. 8 years (Domasov and Lednice) and 3.5 years (Opava) in service, no failures or defects were recorded at any of the sections. This paper gives an update of the research work carried out in 2019 with the latest results from 2023.
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    Portable Telematic System as an Effective Traffic Flow Management in Workzones
    (Transport and Telecommunication Institute, 2015-04-18) Ščerba, Marek; Apeltauer, Tomáš; Apeltauer, Jiří
    Traffic infrastructure localities with temporal restrictions for example due to reconstructions, or modernization, are important aspects influencing the traffic safety and traffic flow. On the basis of our research, we can identify main factors, which generate travel time loses, and which often cause traffic accidents in bottlenecks. First of all, it is improper late merge, speeding, tailgating, lower tolerance and consideration to other road users. Nervousness and ignorance of drivers also play an important role in generation of traffic congestions, lower level of service and resulting external economic loses. One of the tools eliminating the traffic restriction negative impacts is usage of portable telematics systems. In 2011 to 2013,project ViaZONE was in progress, which was to design an intelligent system with the aim to eliminate the mentioned risks and reduce economic losses generated by traffic congestions. Using available data and information, we have proved profitability and cost-effectiveness of dynamic systems for traffic control of work zones. Regarding traffic management, the system showed some problems due to indisciplined drivers and the system proved that speeding in these hazardous road segments is a common practice which caused accidents and congestions.
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    Usage of foamed bitumen in asphalt mixtures
    (Growing Science Ltd., 2020-05-08) Hýzl, Petr; Dašek, Ondřej; Stehlík, Dušan
    This paper focuses on the application of foamed bitumen technology in the production of asphalt mixtures. This technology replaces the common asphalt binder with foamed bitumen for production of asphalt mixtures. Given the foaming, it is possible to produce asphalt mixture at a lower working temperature.
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    Verification and validation of a numerical model of fire and smoke development in a railway tunnel
    (Czech Technical University, 2016-01-01) Cábová, Kamila; Apeltauer, Jiří; Wald, František
    The paper describes the verification and validation of a numerical model of the development of fire and smoke in a railway tunnel carried out in the Fire Dynamic Simulator numerical code. To evaluate the correctness of a numerical solution of the model with respect to the mathematical model, the results are compared with a solution executed in the SmartFire numerical code. The influence of mesh size on the gas temperature results in the vicinity of the fire source is studied. The level of agreement between the numerical model and a physical model is validated by comparing the calculated data with data measured during a fire test in the Valik road tunnel in the Czech Republic.
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    Modernisation of Regional Roads Evaluated Using Ex-Post CBA
    (MDPI, 2021-02-08) Halámek, Petr; Matuszková, Radka; Radimský, Michal
    The aim of this evaluation is to verify the telling value of the Cost and Benefits Analysis (CBA) of regional roads modernisation based on an ex-post evaluation of the investments and their impacts on the incidence of traffic accidents. A set of 144 projects were the subject of evaluation. The analysis of the actual investment costs confirmed the assumption that the majority of projects were planned with a sufficient provision. When compared with the costs foreseen for the entire set of projects, the total reduction of actual costs spent was over 11%. The investigation of project impacts on traffic accidents was based on an analysis done prior to and after construction by using the Czech Police database. The measurement results show only minimum changes in the incidence of traffic accidents in the scenario prior to and after project completion. This however strongly contradicts the project goals declared, because the projects were anticipating almost zero accidents with a fatality and a 50% reduction of accidents with health consequences. However, a slight increase in road fatalities and in light and serious injuries was measured. These facts have a significant impact on the Net Present Value (NPV) and the weighted profitability index for the entire set of projects dropped from 16.7% to 2.8%. The key recommendation is to eliminate the impact on traffic accidents in the case of project evaluations processed ex-ante for projects focused only on a reconstruction or modernisation of existing roads.