THE INFLUENCE OF ROAD CROSS-PROFILE, SUBBASE AND SUBGRADE, AND PRECIPITATION ON THE BEARING CAPACITY OF FLEXIBLE PAVEMENTS

Between 1987 and 1991, eleven series of measurements of the bearing capacity of flexible pavements were carried out in 3 regions of the Republic of Slovenia. The measurements were made on 57 test sections with lengths from 100m to 500m on roads with traffic. The selected test sections have very similar pavement structures and quality of materials, but the subbase and subgrade material varied from clay to sandy gravel and crushed stone. The climatic characteristics varied from harsh winters with mild summers, to a continental climate with harsh winters and hot summers. Three types of cross profile were selected: cut, embankment, and formation level (ground). The aim of these measurements was to determine the influence of subbase and subgrade materials, as well as of the quantity of precipitation and road cross-profile on the bearing capacity results measured by a Lacroix deflectograph improved by the technicians of our Institute. During the project the data on pavement surface temperatures, precipitation, geological and hydrological conditions, the thicknesses and quality of materials in road construction, and the foundation soil constitution were obtained.