PREDICTION OF THE MAXIMUM LEVEL OF TANGENT STRESSES IN THE ASPHALT CONCRETE SURFACE LAYING ON THE CONCRETE BASE OF A MOTOR ROAD

Abstract

In this paper, in order to evaluate the tangential stress levels in the asphalt concrete coating arranged on concrete foundation, finite element modeling of various constructions of road clothing with different values of the thickness of the asphalt layer and its modulus of elasticity, was carried out. The thickness of the asphalt layer varied from 5 cm to 30 cm with a step of 5 cm. The modulus of elasticity of asphalt ranges from 3000 MPa to 9000 MPa. In addition, the position of the transport load in relation to the deformation joint between the slabs of the concrete base varied for different versions of the structures. Calculations using the finite element method show that in this case τxz is the largest tangent component of the stress tensor. Among the different load positions, the option was chosen in which the tangential stress τxz in asphalt reaches a maximum in terms of modulus. Based on the maximum tangential stress values in the asphalt calculated in this way, a surface plot of the function τmax is obtained, which depends on two variables h and E. From the appearance of this surface, it can be seen that τmax increases with decreasing asphalt coating thickness and depends almost linearly on its elastic modulus. For this surface, an approximating function is proposed, with the help of which the level of maximum tangential stresses in the asphalt layer above the expansion joint can be approximately estimated for structures with intermediate values of h (cm) and E (MPa). Based on this surface level diagram, the design parameters of road clothing can be chosen such that the maximum tangential stress level in it is lower than the allowable value.