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From page 103... ... 103 Analysis of Engineering Properties Statistical analyses were conducted to assess whether differences exist between WMA and HMA for the binder properties, mix characteristics, in-place properties, and laboratorymeasured engineering properties. For projects with one WMA and an HMA control, t-tests were used to compare the characteristics and properties that have replicate data with a 95% confidence level (α = 0.05) Read the entire page →
From page 104... ... 104 Variable HMA WMA Mean Difference P-value Significant Pb (TCE) Mean 5.22 5.44 -0.22 0.02 Y SD 0.27 0.21 Tc High Mean 84.9 83.9 1.0 0.28 N SD 6.1 5.1 Tc Intermediate Mean 26.6 26.6 0.0 0.42 N SD 3.9 3.0 Tc Low Mean -19.2 -19.5 0.3 0.42 N SD 5.9 3.9 Tc Mean -6.2 -5.2 1.0 0.14 N SD 3.6 2.3 LAS Low Strain Mean 696,642 513,434 183,208 0.15 N SD 640,729 376,790 LAS High Strain Mean 8,598 5,771 2,827 0.10 N SD 6,593 2,733 JNR3.2 Mean 0.118 0.077 0.04 0.05 Y SD 0.008 0.003 Table 4-1. Read the entire page →
From page 105... ... 105 Location Mix ID Gmm Va (%) Read the entire page →
From page 106... ... 106 Frequency Mixture 4°C 20°C 40°C Avg. Read the entire page →
From page 107... ... 107 Frequency Mixture 4°C 20°C 40°C Avg. Read the entire page →
From page 108... ... 108 A dj . Read the entire page →
From page 109... ... 109 Fl ow N um be r (c yc le s) Read the entire page →
From page 110... ... 110 HMA mixtures indicated that no statistical difference was evident (p-value = 0.153) Read the entire page →
From page 111... ... 111 FW–HMA FW–WMA H M A P G 6 422 15 % R A P– 3% R A S H M A P G 5 828 15 % R A P– 3% R A S Ev o 3G P G 6 422 15 % R A P– 3% R A S H M A P G 6 422 5% R A S Austin Gravel Quartz Illinois Fort Worth Fl ex ib ili ty In de x Figure 4-4. Flexibility index of cores from existing projects (FW = Fort Worth) Read the entire page →
From page 112... ... 112 On average, the quartzite mix had a flexibility index of 10.1 and the gravel mix had a flexibility index of 7.9; however, there was no statistical evidence to conclude that these mixes had different flexibility index values at a confidence level of 95% (p-value = 0.27, two-sample t-test) Read the entire page →
From page 113... ... 113 criteria were used to evaluate the overall performance of all mixtures. Table 4-12 shows that the majority of the mixtures (11 of 15) Read the entire page →
From page 115... ... 115 • Moderate inversely proportional correlation between the true PG high critical temperature and Overlay Test and flexibility index, • Moderate proportional correlation between the true PG intermediate critical temperature and dynamic modulus, • Moderate inversely proportional correlation between the true PG intermediate critical temperature and bending beam fatigue, • Moderate inversely proportional correlation between the true PG low critical temperature and semi-circular bend–Jc, • Moderate inversely proportional correlation between volume percentage of effective binder Vbe and dynamic modulus and flow number, • Strong proportional correlation between the D/B ratio and dynamic modulus and flow number, • Moderate proportional correlation between Pba and dynamic modulus at intermediate and low temperatures, • Strong proportional correlation between Pba and flow number, • Moderate inversely proportional correlation between Pbe and dynamic modulus and IDT critical pavement temperature, • Strong inversely proportional correlation between Pbe and flow number, • Moderate proportional correlation between the percent of material passing the No. 200 sieve (P200) Read the entire page →
From page 116... ... 116 Effect of Material Properties on Laboratory Performance Hierarchical cluster analysis was performed to separate observations by similar groups (Table 4-17) Read the entire page →
From page 117... ... 117 cluster contains mixtures with higher dynamic moduli, lower resistance to fatigue cracking (Overlay Test and Flexibility Index Test) , slightly higher Hamburg rutting, and lower susceptibility to thermal cracking. Read the entire page →
From page 118... ... 118 MW–RAS–MW–RAS –B et a– G am m a MW–RAS NC HMA MW–RAS NC HMA PC–RAS Figure 4-6. Relaxation spectra parameter versus inflection point. Read the entire page →
From page 119... ... 119 R² = 0.9944 R² = 0.9882 R² = 0.992 0 5 10 15 20 25 30 35 40 4 4.5 5 5.5 6 6.5 Ph as e An gl e (d eg re es ) Read the entire page →
From page 120... ... 120 The greater the dynamic modulus inflection point (towards the right) , the stiffer and/or more oxidized the mixture. Read the entire page →
From page 121... ... 121 From the overall combined rank, the top five are all WMA mixtures; and within each project, the WMA mixtures rank higher than the HMA mixtures. Bending beam fatigue results were not included in the analysis because of the difference in procedures used to obtain the number of cycles to failure on the first project. Read the entire page →
From page 122... ... 122 low-temperature cracking -- are WMA mixtures. The two Indiana mixtures are the stiffest at this temperature and frequency. Read the entire page →
From page 123... ... 123 Table 4-19. Ranking comparison among low-temperature performance parameters. Read the entire page →

From page 103...

... 103 Analysis of Engineering Properties Statistical analyses were conducted to assess whether differences exist between WMA and HMA for the binder properties, mix characteristics, in-place properties, and laboratorymeasured engineering properties. For projects with one WMA and an HMA control, t-tests were used to compare the characteristics and properties that have replicate data with a 95% confidence level (α = 0.05)