The difficulties and uncertainties in the stability evaluation of embankments composed of, or founded on, materials with different engineering characteristics have long confronted geotechnical engineers. Failure of these structures frequently occurs, despite careful investigation, testing and analysis procedures.
The use of graded crushed stone as basecourse material is an economical and reliable alternative to using bituminous materials, provided that the crushed stone has adequate density. Density specifications of crushed stone in terms of apparent density can sometimes lead to unrealistic requirements being set that the contractor cannot meet, because no indication of compactability is obtained with this test. This paper dealt with a laboratory invesligalion into the factors that affect the compaction of crushed stone. The influence of grading and the shape and texture of the aggregates on compactabllIty was evaluated, and a method was given whereby the compactability of crushed stone can be predicted. The influence of moisture content was also investigated and it was found that the optimum moisture content is often at or near the saturation point.