Distribution of temperature, moisture, stress and strain in the highway
The paper analyzes regularities for the distribution of temperature, moisture, stresses and strains in pavement and subgrade of the highway, located in northern part of Kazakhstan, within one year, especially during cold season. Distribution of temperature and moisture has been determined experimentally with the use of special sensors. Stresses and strains have been calculated with the use of elastic multilayer semi-space model. It has been shown that the stiffness (elasticity modulus) of asphalt concrete layers and upper part of subgrade soil increases considerably during cold winter season: up to 18000 MPa and 10000 MPa respectively. All the components of stresses and strains vary considerably in points of pavement and subgrade during the annual cycle. Variations of pavement surface deflection and horizontal stress in the bottom asphalt concrete layer are of quasi harmonic nature, and horizontal strain in this point varies under the quasi bicyclic law. Horizontal stress during the cold season is a tensile one and has the biggest value, and during hot season it changes its sign and becomes the compressive one. Horizontal strain during the whole annual cycle remains only a tensile one. The biggest variations of stresses and strains occur in the upper part of subgrade. During cold season the vertical compressive stresses and strains are the minimal ones, and in the beginning of spring they are the maximal ones.