Tytuł Data publikacji Autor
The phenomenon of vehicle overloading—illegal exceeding of maximum legal weight of vehicles, is a serious problem both in developing and developed countries around the world. Overloaded vehicles occur less frequently in comparison to properly loaded vehicles but due to their greater potential to cause damage they significantly contribute to distress of pavement structure. As studies show, the number of overloaded vehicles increases when the control of traffic is insufficient. Weigh in Motion (WIM) systems significantly improve control level and contribute to decrease in the number of overloaded vehicles. Data delivered from WIM were used to perform statistical analysis of vehicle overloading in Poland. The average percentage of overloaded vehicles (OV) in Poland varies from 5% for roads with high enforcement level to 23% for roads where control is poor. Every weighed vehicle was considered in terms of exceeding maximum legal gross weight and maximum legal axle load. For each vehicle separately truck equivalency factors were calculated. Subsequently the relationship between average values of truck equivalency factors and percentages of overloaded vehicles was found. This relationship was used as a basis to determine the impact of overloaded vehicles on decrease in fatigue life of pavement structure (DFL) and increase factor IF, which expresses the extension of service period. It was proved that reduction of overloaded vehicles from 23 to 5% will contribute to increase in service period of pavement structures by factor 1.5. The life cycle cost analysis (LCCA) was performed for two levels of overloading OV = 23% and OV = 5%. The paper revealed that improvement of vehicle control and reduction of the percentage of overloaded vehicles from 23 to 5% will cause the reduction of whole life cost borne by road authority by 11%. 1 Introduction
2019
Dawid Ryś,
Piotr Jaskuła
The article presents the observed deviations from the time-temperature superposition principle of asphalt concretes, tested in the bending beam creep test at low temperatures for a long time of loading. In almost all tested asphalt concretes, deviations appeared after 500 s of loading at the temperature of -10 C. Some types of bitumen presented deviations at other temperatures – usually the harder the grade of the bitumen, the higher was the temperature of appearance of deviation. The article investigates also the impact of the following factors on the described deviations: type of bitumen, assumed time of loading and level of loading.
2019
Mariusz Jaczewski,
Józef Judycki,
Piotr Jaskuła
The paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the material-defining parameter values. Such a random approach leads to the mean values of breaking and fracture-triggering loads, dealing with their dispersion too. The estimated parameters allow to form appropriate numerical models of asphalt mixture specimens. This type of analysis supports the laboratory tests. The paper presents the authors' simplified model considering non-uniform material features. The results reflect the scatter of real laboratory test outcomes. In order to do so an algorithm to calibrate the numerical model parameters was created.
2019
Cezary Szydłowski,
Jarosław Górski,
Marcin Stienss,
Łukasz Smakosz
The paper presents the results and analysis of low-temperature properties of asphalt mixtures according to Thermal Stress Restrained Specimen Test (TSRST) and Indirect Tensile Test methods. Different groups of bitumen were investigated: neat, SBS-modified and highly SBS-modified. Influence of cooling rates (1 C/h, 3 C/h, 5 C/h and 10 C/h) and additives (aramid fibres and crumb rubber) was identified as well. Moreover, for each factor stiffness moduli were back-calculated from the TSRST results and analysed. The greatest impact on the TSRST results had type of bitumen, followed by the cooling rate and additives. Application of longer fibres improved low-temperature properties of the asphalt mixtures.
2019
Marek Pszczoła,
Cezary Szydłowski,
Mariusz Jaczewski
The paper presents application of equivalent temperature for design of asphalt pavements. The calculation methods of equivalent temperature: the Shell method, the French method, the methods that use the AASHTO and the Asphalt Institute fatigue criteria were presented. The results of calculations of equivalent temperature for Polish climatic conditions were presented and discussed. It was shown that different asphalt pavement design methods and utilization of Polish climatic data resulted in various calculated values of equivalent temperature that could be used in the design process.
2019
Marek Pszczoła
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