Certain elements of the currently used Hungarian pavement design method are based on the mechanistic-empirical pavement design principles, although they are not always readily implemented in practice. When designing a new pavement structure, it is only possible to select predetermined composition from a catalogue. The use of the Hungarian design catalogue is unquestionably comfortable, but nowadays special requirements (e.g. economy, sustainability) have been formulated as well. Those requirements increasingly call for the development of a method that can be used under Hungarian conditions, which can provide for the employment of various material properties. Instead of offering a predefined solution it needs to provide a useful tool for designers to enable realistic comparisons of engineering alternatives. This paper introduces the results of an ongoing research that aims to provide an alternative procedure for the design of newly constructed asphalt pavements. It establishes the framework for better characterization of the material properties of the natural subgrade and bound pavement layers compared to the utilization of predetermined designs. It also provides opportunity to consider local, environmental, geographical and other conditions and innovative building and technology capabilities.

The concept of ecologically conscious and energy saving roads must be expanded to the performance of the asphalt mixtures as well as to the test related to it. This paper investigates the tests focusing on a better description of the behaviour of asphalts as well as on a deeper revelation of the impact of different compositions. Based on the international experiences the recording of the asphalt's complex module over the entire temperature range by the determination and evaluation of the mater-curves appeared as a possible solution for more precise description of the asphalt behaviour.

There are a number of sustainable and environmentally friendly techniques and methods currently available in the construction industry. To promote sustainable development, different rating and certificating systems that evaluate the level of sustainability during the development of infrastructure construction projects have been developed. The aim of the research presented in this paper was to examine the applicability of sustainability rating systems in Hungary and find the most suitable option. After a review of commonly used rating systems, i.e., Greenroads, GreenLITES, I-LAST, Envision, and INVEST, the most suitable existing rating system is selected with the help of the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) mathematical decision analysis method. This was achieved by utilizing 12 categories of input data (weights) analyzed through TOPSIS. The input data (weights) of the TOPSIS method were determined by a small research group of industry experts and academic professionals based on Hungarian practices and methodology. As a result of the calculation, the study found that the Envision rating system satisfies the criteria best, closely followed by Greenroads.

-The paper introduces a new method for calculating the elastic moduli of pavement layers. The method requires only two input parameters: the thickness of the upper "bound" layer and the Falling Weight Deflectometer (FWD) or Improved Benkelman Beam Apparatus (IBBA) measurement data. The authors developed a continuously differentiable regression function, which can be applied to describe the shape of the deflection bowl. Additional parameters of the deflection bowl (e.g. radius of curvature, position of inflexion point) can be calculated based on the regression function. FWD measurements were simulated running the BISAR (Bitumen Stress Analysis in Roads) software on different pavement variations. Outputs of the simulations were further processed with self-developed software. As a result, a series of diagrams were elaborated, by which the elastic moduli of the pavement layers can be determined. Stiffness / pavement layers / elastic moduli / deflection bowl / BISARKivonat -A pályaszerkezet merevségének hatása a behajlási teknő alakjára. Útpályaszerkezetek esetében a megfelelő rehabilitációs eljárás kiválasztása igen nagy gazdasági jelentőséggel bír. Ezért a szerkezetek állapotának megfelelő ismerete nélküli döntéshozatal igen költséges lehet. Emiatt különösen fontos, hogy az FWD (Falling Weight Deflectometer) vagy IBBA (Improved Benkelman Beam Apparatus) eszközzel mért elmozdulások elemzésével olyan többletinformációhoz jussunk, ami a döntést megkönnyíti a gyakorló mérnök számára. Az FWD vagy IBBA eszközzel mért deformációs vonalra illesztett függvényből levezetett görbületi sugár (R 0 ) és a burkolatvastagság (h) ismeretében a kötött rétegek alján jelentkező megnyúlásokat jól lehet becsülni. A BISAR (Bitumen Stress Analysis in Roads) programmal végzett számítások statisztikai elemzése pedig azt mutatja, hogy a D 0 (központi behajlás) és R 0 (görbületi sugár) paraméterek ismeretében lehetőség nyílik a kötött és szemcsés rétegek modulusának visszaszámolására. Merevség / pályaszerkezet rétegek / rugalmassági modulus / behajlási teknő / BISAR

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Abstract

The aim of this research study was to analyse the approaches for establishing a spatial model of a radial truck tyre, based on the finite element method, in order to perform a realistic analysis of static as well as dynamic tyre–pavement interactions. A complex rubber tyre model having a large number of elements was formulated combining current state-of-the-art modelling techniques and, from that model, a simplified model having a smaller number of elements was derived. The complex model proved to be useful only for static loading, because of its high computational demand, while the simplified model proved to be also suitable for dynamic modelling. The two tyre models having different numbers of elements were compared by analysing the contact areas and stresses. Our results indicate that the basic idea of not changing material characteristics while simplifying the model, rebuilding only the carcass using composite shell elements, did not prove to be a satisfactory direction. The results given by the simplified model do not describe the behaviour of the radial tyre well but, rather, describe the behaviour of the diagonal tyre, regarding contact areas and stresses. On the contrary, when analysing stresses and strains in the road pavement structure, the two finite element models provided similar results in practice. Based on our comparison calculations, applying the average contact pressure q at analysis points at a 5–8 cm depth, the contact behaviour of the finite element tyre model can be used in any elastic-layer theory-based software.

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