Relative Compaction of Fill Having Oversize Particles

Three methods used to determine the relative compaction of fill having oversize particles are compared. For the purpose of this study, oversize particles are defined as rock that is retained on the 3/4-in. (19-mm) sieve, while the soil matrix is the material passing the 3/4-in. (19-mm) sieve. The three methods are the elimination method, adjusted maximum dry density method, and the substitution method. The three methods did not give the same results for the tested soil. Assuming a fill that must be compacted to 90% relative compaction, the elimination method would require the highest field dry density, while the adjusted maximum dry density method would require the lowest field dry density. For fill that contains large amounts of oversize particles, the adjusted maximum dry density method should be used with caution, since this method can result in low dry density values of the soil matrix.