Certain Mechanisms of Thermostress Field Variations in Layered Pavement Structures

Abstract

Refined mechanical and mathematical models of pavement deformation and strength were constructed for different structural schemes, materials, and impact of transport and thermomechanical loads. The final stage of computer analysis resulted in the construction of mathematical models with finite element approximation in the form of linear algebraic equations of higher order. They can be used to analyze the initiation of fractures under the action of time-varying temperature perturbations in view of changes in the stiffness characteristics of the pavement material. The distribution of temperature fields in the pavement structure, irrespective of its comparatively simple geometric schemes and shapes, causes the functions of thermal perturbation, involved in thermoelastic phenomena, to become much complicated. It makes those phenomena nontrivial and their simulation labor-intensive. The medium of temperature field evolution is nonuniform layered, and its simulation at chosen thermomechanical characteristics and sizes of an examined area belongs to the class of singularly perturbed. On the external thermal perturbation, the heat flow is not managed to penetrate from the boundary surface deep into the bulk and the temperature field would be noticeably changed only in a narrow zone, acquiring the form of the so-called boundary effect. The temperature function not only essentially increases in the boundary zone but also its gradients acquire high values, i.e., the derivatives with respect to spatial variables that generate intensive stress fields. The effects of rearrangement of temperature and stress fields in nonuniform layered pavement structures under daily and seasonal changes in environmental temperature are examined.