Determining the most dangerous loading application point for asphalt-concrete layers on a rigid base

Abstract

Operating conditions of asphalt-concrete layers on cement-concrete slabs differ significantly from other structural solutions. Practical road construction applies the insufficiently developed methods for calculating the strength of asphalt-concrete coating for rigid road beds since only separate strength criteria of the asphalt-concrete layer are standardized. Current calculation methods do not take into consideration the patterns in the stressed-strained state of an asphalt-concrete layer on cement-concrete slabs under various conditions for the application of load, such as the middle part of a slab, the edge of a slab, and the corner of a slab. The mismatch between the conditions for calculation and the actual stressed-deformed state of a structure predetermines the premature failure of an asphalt-concrete layer and, consequently, shortens the inter-maintenance period and leads to additional costs for unplanned repair.We have simulated the stressed-strained state of a road bed structure by using a finite-element method in the programming environment ANSYS for three variants of arrangement of transport loading, specifically in the center of a slab, at the edge of a slab, and in the corner of a slab.The paper provides, for the accepted variants of the transport loading, the derived values for the von Mises stresses, principal stresses, horizontal and maximal horizontal shear stresses. The stresses' values were determined at the surface of an asphalt-concrete layer, at a point of contact between an asphalt-concrete layer and a cement-concrete slab, and at a contact point between a cement-concrete slab and a base.We have compared the defined stresses in the layers of a road bed for different variants of the application of a transport loading, as well as compared the results obtained with known solutions.That has made it possible to establish that for the asphalt-concrete layer the arrangement of load in the corner of slab is the most dangerous, both in terms of shear stresses and the von Mises stresses. The stresses that occur when the load is applied at the corner of a slab are approximately 10 % higher than the stresses that occur when the load is applied at the edge of a slab, and are approximately 20 % higher than the stresses arising when the load is applied in the center of a slab.