COMPUTATION OF ROAD STRUCTURES WITH GRANULAR BASE COURSES . THIRD INTERNATIONAL CONFERENCE ON BEARING CAPACITY OF ROADS AND AIRFIELDS. PROCEEDINGS, NORWEGIAN INSTITUTE OF TECHNOLOGY, TRONDHEIM, NORWAY, JULY 3-5 1990. VOLUMES 1-2

This paper discusses calculations of the characteristics of road structures consisting of an asphalt layer, a base layer and a 5 m thick sand package. The structures had variable thickness of both asphalt and base layers and used different granular materials in the base layer. The results of the calculations are compared with measurements of tensile strain at the bottom of the asphalt layer of test pavements. The test pavements contained sections with bases consisting of different granular materials, ranging from sand to unbound materials like lava and self-cementing materials like crushed concrete. The measurements were performed at the Road and Railroad Research Laboratory, Delft University of Technology, Netherlands. The following results were obtained: (1) in agreement with theory, the experiments found that the G-modulus and K-modulus of granular materials increase with the spherical pressure; (2) triaxial tests showed that Poisson's ratio could increase by over 50%, because of 'elastic dilation'; (3) in several cases, the measured and calculated asphalt strains agreed well, and deviations in other cases could be explained; (4) calculations with the nonlinear elastic model approximated the measured asphalt strains reasonably well. (TRRL)