EFFECT OF MOISTURE ON THE STRUCTURAL PERFORMANCE OF A CRUSHED-LIMESTONE ROAD BASE

Abstract

A series of repeated load triaxial tests on a crushed-rock aggregate is described, including variations in grading and degree of compaction as well as moisture content. The effects of these variables are discussed and it is found that elastic stiffness tends to decrease slightly with increased moisture content for broadly graded materials. The influence of density is negligible, and that of grading minor, which results in some stiffness reduction as the fines content increases. The accumulation of permanent strain under multicycle loading is found to be strongly dependent on density; denser material performs better. Grading has a minor effect. Increased moisture content results in substantially increased straining. The value of suction, which could exist in a granular material, is then explored indirectly by means of unconfined compression tests, and its effect on drainage is noted. Permeability measurements are given and their possible effect on drainage considered. Finally, computations are presented that illustrate the influence of partial and full saturation of a base layer of a pavement structure.