using a Tukey test was performed to evaluate whether differences between any two pairs
of category means were significant. Table 5.6 displays the means for groups in
homogeneous subsets. According to Table 5-6, only the dynamic modulus values for the
first category (combination of Low nca and Low nfa) are significantly different from the
other category groups at an alpha level = .05. This means that if nca is less than 0.5 and
nfa is less than 0.59, a "high" dynamic modulus will likely be obtained for a given
aggregate type and asphalt grade.
Table 5-4. Mean and standard deviation of |E40*| for the four different categories
Category Groups N Mean Std. Deviation
Low nca + Low nfa 3 1000.00 105.14
Low nca + High nfa 3 709.00 150.80
High nca + Low nfa 4 673.25 128.76
High nca + High nfa 3 540.33 90.61
Total 13 726.23 198.83
Table 5-5. One-Way analysis of variance (ANOVA) of |E40*| (total N=13)
Sum of Squares df Mean Square F Sig.
Between Groups 340640.89 3 113546.96 7.64 0.008
Within Groups 133763.41 9 14862.60
Total 474404.30 12
Table 5-6. Post-Hoc analysis for homogeneous subsets of hypothesized categories
Subset for alpha = 0.05
Group N Statistically Not statistically
Significant Significant
Low nca + Low nfa 3 1000.00
Low nca + High nfa 3 709.00
High nca + Low nfa 4 673.25
High nca + High nfa 3 540.33
Category Analysis of Power Law Parameters for Coarse and Fine Graded Mixtures
The mixtures in Table 5-1 were divided into two subsets, depending on whether the
mixtures were coarse-graded or fine-graded, according to the Superpave mixture design