almost all of the comparisons. The comparisons (also confirmed
by Bartlett’s test) show that there should be two levels
of precision: one for materials with absorptions of less
than 2.5 percent (Elmore gravel, Preston sandstone, and RC
limestone) and another level for more absorptive materials
(blast furnace slag and recycled concrete). Thus, the precision
information determined in this study for the two methods
for coarse aggregate are shown in Table 3-17. The precision
information was determined based on limited data generated
in this project, so a round robin is needed to verify this precision
information prior to future implementation. Table 3-17
also includes the precision information (based on aggregates