In addition to the statistical significance analyzed above,
the practical significance of the aggregate specific gravity test
results also was determined for concrete and asphalt mix design
methods. The practical ranges of the within-lab precision
estimates for Gsb determinations are reasonable for concrete.
However, for asphalt, the Gsb test result has a very large impact
on VMA, one of the more critical criteria for asphalt mix design
and acceptance. To reduce the impact on VMA to a tolerable
level, the acceptable range of differences between within-lab
replicates alternative methods would have to be less than 0.010,
which is about one-third of what is currently practically
attainable.