CRD-C130-01 Standard Recommended Practice for Estimating Scratch Hardness of Course Aggregate Particles
This recommended practice describes a method of estimating the quantity of soft particles in coarse aggregates on the basis of scratch hardness. It is intended to be used to identify materials that are soft, particularly those which are so poorly bonded that the separate particles in the piece are easily detached from the mass. The test is not intended to identify other types of deleterious materials in aggregates, separate mention of which should be made in specifications.