The effect of grading and density on the mechanical properties of a crushed dolomitic limestone

Abstract

This paper describes laboratory tests on specimens of dry, crushed, dolomitic limestone of different gradings carried out in order to determine the characteristics necessary for use in pavement design and evaluation computations involving analytical methods. A servo hydraulically controlled repeated load triaxial test facility was used for the tests. Seven gradings were investigated, ranging from single sized to very broadly graded, but all with the same maximum particle size of 10 mm. Three specimens were made at each grading, using difference compactive efforts, in order to investigate the influence of density on the mechanical properties. Results are presented which show the comparative insensitivity of elastic stiffness to both density and grading and the dominant influence of density on shear strength and resistance to plastic straining under cyclic load. The relative merits of uniform and broadly graded materials are compared in the light of these tests and also with respect to effects from the presence of moisture, including both suction and possible positive pore pressures (a).