INFLUENCE OF WHEEL LOAD AND INFLATION PRESSURE ON THE RUTTING EFFECT AT ASPHALT-PAVEMENTS - EXPERIMENTS AND THEORETICAL INVESTIGATIONS. SIXTH INTERNATIONAL CONFERENCE, STRUCTURAL DESIGN OF ASPHALT PAVEMENTS, VOLUME I, PROCEEDINGS, UNIVERSITY OF MICHIGAN, JULY 13-17, 1987, ANN ARBOR, MICHIGAN

The presented paper includes a study of the influence of wheel loading and inflation pressure on the rutting effect at asphalt-pavements. The statements are based on laboratory-tests with single tire equipment as well as with twin tire equipment and on theoretical investigations. The tests were performed with a test facility which enables full-scale rutting tests with loading by real tires, test specimens of natural dimension, and practical temperatures. In the here described test series only the parameters wheel loading, inflation pressure, and tire arrangement (single tire, twin tires) were varied. The pavement system, the temperature gradient (according to the relevant temperatures of a hot summer-day), and the speed in test were not changed. The rutting development was measured by superimposed transverse surface profiles. The dependence of rutting on the influence parameters loading number, wheel load, and inflation pressure was determined by regression analysis. The theoretical investigations were based on the elastic multi-layer theory using computer program BISAR of SHELL whereby deformation was separated from general strain. The calculated deformations were compared with the test results. With the results of theoretical calculation the test results could be completed or extended. The tests and the theoretical investigations have shown that the wheel load, the inflation pressure, the average contact pressure between tire and pavement surface (depending on both factors), and the tire arrangement have an important influence on the rutting effect. With regard to the design of heavy trucks these parameters need a particular consideration.