PAVEMENT STRENGTHENING USING UNBOUND MATERIALS

The aim of the present study was to examine how the elasticity of crushed gravels can be determined by means of their grain size distribution. The study focused especially on the elastic modulus of crushed gravel. The material used in the study consists of the results of bearing capacity and density measurements of road embankments, which were gathered from the Roads and Waterways Administration's quality control reports (1974-1980). It also consists of the determination of the grain size distribution of layer materials used from a total of 108 building projects and 380 road kilometres. Because of the measuring arrangements only data for the analysis of the base course were available. Therefore the study had to be limited to the base course only. The work was done in two parts. First, the elastic moduli of the layer materials were calculated by means of measurements of the bearing capacity and the thickness of the layer. The calculations were based on the dimensioning formula developed by Nils Odemark. In the second phase the interdependence of the above calculated elastic moduli and the key figures, which were determined from the grading curve, were examined by means of statistical mathematical methods. It was found that the modulus of elasticity of the base course material can be calculated using the grading curve parameters, this, however, in limited conditions (moisture, temperature). (Author/TRRL)