The Selected Problems of Multi-layer Pavements – Influence of Composite Impacts Vehicles and Climatic Factors on the Behavior of Roads Pavements

Abstract

Multi-layer pavement models, which utilize solutions such as the one of Boussinesq, Burmister, Kogan, Odemark and others, contain many simplifications that have a significant influence on the estimated real value of stress, strain, deflection as well as on the coefficient of pavement layers interaction. In the article based on the experiments carried out, we want to present our own layered-pavement models and solutions to them, which can be used mainly in the diagnostics of bearing capacity. The estimation of bearing capacity is conducted on the basis of full time data obtained with the FWD device. In order to prove the climatic factors impact on the bearing capacity of the multilayer pavement structure a theoretical analyses of the joined dynamic and thermal impacts has been performed. Additionally qualitative and quantitative changes of road surface deflection in a thermo-viscoelastic model were presented. In the proposed model it was examined the impact of the relevant climatic factors, inter alia, such as: stream of solar radiation, humidity and wind speed on the surface pavement deflection bowl under load dynamic. Moreover, the conclusions implicated by the above mentioned analysis are of big importance in design and operation process of road and airfield pavements. They pertain not only to the influence of modulus and thickness of particular layers but also to the way of pavement layers interaction, Poisson's coefficient and others.

Multislice Spiral CT Imaging Localization and Nursing Care of Catheter Fracture of Scalp Vein Indwelling Needle

“…Using Siemens Somatom Definition 64-layer spiral CT, application of full automatic intelligent current selection techniques (ACSs) from the lower jaw to the conventional location and parietal scanning [ 8 ]. After the scan is completed, the automatic reconstruction data will be transmitted to the SyngommvvpVE23 A workstation, and the image will be reconstructed jointly with InSpace software and NenroDSA software.…”

Archives of Civil Engineering

“…2. Geometric model of a homogenized pavement in detail in [24]. These criteria concerned, in particular, the equivalence of mass, equivalence of internal energy, equivalence of the temperature differential between the top (outer) surface and the subgrade, equivalence of parameters describing the wave propagation of heat in a multi-layer pavement system and its homogenized equivalent.…”

“…Comparing the results obtained for the layered and homogenized models we observe good consistency between the temperature distributions. The temperature differences result primarily from the methods of calculating the average values of the thermal quantities from the constants of leptokurtic distribution given in [24] which consider primarily the effect of thickness of a given layer assuming uniform temperature distribution in it. This problem will be solved by modifying the layered pavement system homogenization method.…”

“…Similar classical heat conduction problems of the layer/subgrade system are presented in [21] and [22].…”

“…The nomographs relating to homogenization, which we used in these calculations, come from [24] where they are given in numerical version.…”