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15 Confined 40 C Confinement, +2% 40 C 20 C 4C -Teflon / +Latex - Milled / +Sawed -Without / +With Membrane Strain, +25 microstrain -Water / +Air Time, min Temperature, +0.5 C -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 Change in Dynamic Modulus, % Figure 6. Effect of statistically significant ruggedness factors on the dynamic modulus. outside the membrane, the membrane affects the defor- phase angle, these tables present p-values indicating the sig- mation measurements. nificance of the regression coefficients for each of the factors included in the ruggedness experiment. Again to highlight the important effects, p-values of 0.10 or less are shown in bold. 2.2.2 Factors Affecting Data Table 19 presents a summary table with the percentage of Quality Indicators times a specific factor was found to be significant. The notes Similar analyses were performed for the data quality indi- indicate when a factor was significant for only one laboratory cators. The results are summarized in Table 15 and Table 16 or only one material. Like the measured material properties, for tests in AAT's laboratory using the ITC equipment and in the data quality indicators were not affected very often by the Table 17 and Table 18 for tests in the FHWA's laboratory ruggedness factors. The sections that follow discuss each of using the IPC equipment. Like the tables for modulus and the data quality indicators. Confined 40 C Confinement, +2% 40 C 20 C 4C -Teflon / +Latex - Milled / +Sawed -Without / +With Membrane Strain, +25 microstrain -Water / +Air Time, min Temperature, +0.5 C -4 -3 -2 -1 0 1 2 3 4 5 Change in Phase Angle, Degree Figure 7. Effect of statistically significant ruggedness factors on the phase angle.

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16 Table 15. Significance of dynamic modulus ruggedness test factors on data quality indicators for the dense mixture tested in AAT's Laboratory with the ITC SPT. Factors Load Standard Error Deformation Standard Error Deformation Uniformity Phase Uniformity 4C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 20 40 40 C Confined Confined Confined Confined Equilibrium Temperature 0.67 0.62 0.66 0.85 0.68 0.05 0.09 0.16 0.01 0.50 0.78 0.71 0.98 0.94 0.69 0.97 Transfer time 0.75 0.54 0.79 0.75 0.82 0.61 0.61 0.73 0.15 0.52 0.69 0.70 0.22 0.81 0.06 0.76 Conditioning Fluid (Water vs Air) 1.00 0.69 0.20 0.73 0.95 0.08 0.54 0.09 0.78 0.94 0.17 0.34 0.28 0.51 0.02 0.38 Strain Level 0.06 0.30 0.05 0.45 0.07 0.13 0.09 0.05 0.01 0.89 0.06 0.74 0.46 0.35 0.00 0.04 Membrane (No vs Yes) 0.34 0.10 0.88 NA 0.25 0.00 0.72 NA 0.21 0.99 0.81 NA 0.28 0.35 0.76 NA Confinement (135 vs 145 kPa) NA NA NA 0.38 NA NA NA 0.41 NA NA NA 0.32 NA NA NA 0.92 End Condition (Mill vs Saw) 0.68 0.32 0.81 0.40 0.78 0.32 0.99 0.46 0.26 0.53 0.21 0.48 0.19 0.31 0.20 0.66 Friction Reducer (Teflon vs Latex) 0.84 0.37 0.56 0.97 0.76 0.01 0.94 0.29 0.31 0.37 0.25 0.59 0.95 0.50 0.12 0.08 Table 16. Significance of dynamic modulus ruggedness test factors on data quality indicators for the SMA mixture tested in AAT's Laboratory with the ITC SPT. Factors Load Standard Error Deformation Standard Error Deformation Uniformity Phase Uniformity 4C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 20 40 40 C Confined Confined Confined Confined Equilibrium Temperature 0.70 0.59 0.33 0.01 0.64 0.61 0.70 0.74 0.50 0.07 0.59 0.24 0.57 0.62 0.32 0.89 Transfer time 0.65 0.74 0.19 0.13 0.70 0.86 0.07 0.12 0.87 0.22 0.39 0.00 0.07 0.23 0.34 0.49 Conditioning Fluid (Water vs Air) 0.58 0.09 0.84 0.62 0.51 0.37 0.69 0.28 0.62 0.57 0.78 0.53 0.68 0.91 0.41 0.90 Strain Level 0.06 0.22 0.01 0.58 0.08 0.71 0.85 0.30 0.91 0.86 0.80 0.30 0.69 0.13 0.47 0.60 Membrane (No vs Yes) 0.69 0.54 0.62 NA 0.55 0.17 0.41 NA 0.68 0.84 0.94 NA 0.85 0.47 0.41 NA Confinement (135 vs 145 kPa) NA NA NA 0.46 NA NA NA 0.27 NA NA NA 0.00 NA NA NA 0.04 End Condition (Mill vs Saw) 0.62 0.36 0.71 0.16 0.74 0.33 0.89 0.03 0.08 0.19 0.86 0.02 0.92 0.26 0.36 0.52 Friction Reducer (Teflon vs Latex) 0.55 0.29 0.36 0.23 0.71 0.93 0.75 0.30 0.76 0.91 0.24 0.66 0.07 0.33 0.30 0.03 Table 17. Significance of dynamic modulus ruggedness test factors on data quality indicators for the dense mixture tested in FHWA's Laboratory with the IPC SPT. Factors Load Standard Error Deformation Standard Error Deformation Uniformity Phase Uniformity 4 C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 20 40 40 C Confined Confined Confined Confined Equilibrium Temperature 0.33 0.01 0.44 0.98 0.10 0.79 0.90 0.76 0.35 0.33 0.53 0.15 Transfer time 0.93 0.42 0.29 0.17 0.06 0.62 0.05 0.62 0.33 0.57 0.27 0.10 Conditioning Fluid (Water vs Air) 0.38 0.47 0.29 0.52 0.19 0.04 0.74 0.33 0.38 0.38 0.54 0.86 Strain Level 0.18 0.00 0.24 0.33 0.14 0.43 0.26 0.87 0.73 0.46 0.51 0.03 Membrane (No vs Yes) 0.93 0.11 NA 0.65 0.39 NA 0.92 0.81 NA 0.06 0.21 NA Confinement NA NA 0.28 NA NA 0.65 NA NA 0.16 NA NA 0.37 End Condition (Mill vs Saw) 0.54 0.16 0.40 0.08 0.64 0.17 0.07 0.16 0.72 0.84 0.12 0.02 Friction Reducer (Teflon vs Latex) 0.53 0.11 0.30 0.42 0.79 0.34 0.27 0.62 0.34 0.31 0.18 0.17 Table 18. Significance of dynamic modulus ruggedness test factors on data quality indicators for the SMA mixture tested in FHWA's Laboratory with the IPC SPT. Factors Load Standard Error Deformation Standard Error Deformation Uniformity Phase Uniformity 4 C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 C 20 C 40 C 40 C 4 20 40 40 C Confined Confined Confined Confined Equilibrium Temperature 0.06 0.08 0.00 0.09 0.91 0.31 0.00 0.88 0.67 0.55 0.10 0.83 0.30 0.24 0.67 0.68 Transfer time 0.14 0.26 0.03 0.90 0.22 0.78 0.85 0.13 0.60 0.90 0.68 0.49 0.48 0.43 0.80 0.97 Conditioning Fluid (Water vs Air) 0.16 0.42 0.01 0.00 0.52 0.16 0.01 0.03 0.98 0.10 0.08 0.80 0.67 0.75 0.56 0.77 Strain Level 0.18 0.08 0.00 0.00 0.29 0.04 0.63 0.95 1.00 0.35 0.14 0.45 0.29 0.77 0.79 0.96 Membrane (No vs Yes) 0.67 0.49 0.00 NA 0.26 0.71 0.00 NA 0.24 0.19 0.21 NA 0.09 0.22 0.38 NA Confinement NA NA NA 0.01 NA NA NA 0.76 NA NA NA 0.69 NA NA NA 0.72 End Condition (Mill vs Saw) 0.57 0.97 0.03 0.44 0.83 0.25 0.75 0.44 0.26 0.83 0.90 0.65 0.26 0.54 0.75 0.96 Friction Reducer (Teflon vs Latex) 0.60 0.53 0.19 0.11 0.78 0.67 0.83 0.55 0.49 0.41 0.51 0.62 0.33 0.65 0.73 0.33

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17 Table 19. Percentage of times each ruggedness factor was found to be significant. Load Standard Deformation Deformation Phase Error Standard Error Uniformity Uniformity Equilibrium Temperature 40 27 20 0 Transfer time 71 13 13 202 Conditioning Fluid (Water vs Air) 20 33 131 72 Strain Level 53 40 132 20 Membrane (No vs Yes) 182 18 0 181 Confinement 251 0 0 252 End Condition (Mill vs Saw) 71 13 20 71 Friction Reducer (Teflon vs Latex) 0 72 0 202 Notes: 1 SMA Mixture in FHWA Laboratory with IPC 2 AAT Laboratory with ITC 2.2.2.1 Load Standard Error During Phase II of this project a maximum deformation standard error of 10 percent was associated with good qual- The load standard error is a measure of how well the SPT ity data (11). For the deformation standard error, transfer applies a sinusoidal loading to the specimen. During Phase II time, confinement, end condition, and friction reducers did of this project, a maximum load standard error of 10 percent not appear to affect the results. The effects of the remaining was associated with good quality data (11). For the load stan- factors are shown in Figure 9. From Figure 9, it is clear that dard error, transfer time, end condition, and friction reducers the deformation standard error for high-temperature tests is did not appear to affect the results. The effects of the remain- higher when water is used as the conditioning fluid and when ing factors are shown in Figure 8. Although some ruggedness the unconfined dynamic modulus is measured with the factors were statistically significant, it is clear from Figure 8 membrane in place. These two conditions should, therefore, that these have only a minor effect on the load standard error be avoided. when the allowable range of 10 percent is considered. 2.2.2.2 Deformation Standard Error 2.2.2.3 Deformation Uniformity The deformation standard error is a measure of how close The deformation uniformity is a measure of how close the the deformations measured in the SPT are to a sinusoid. individual deformation measurements made on a sample Confined 40 C Confinement, +2% 40 C 20 C 4C -Teflon / +Latex - Milled / +Sawed -Without / +With Membrane Strain, +25 microstrain -Water / +Air Time, min Temperature, +0.5 C -10 -8 -6 -4 -2 0 2 4 6 8 10 Change in Load Standard Error, Percent Figure 8. Effect of statistically significant ruggedness factors on the load standard error.

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18 Confined 40 C Confinement, +2% 40 C 20 C 4C -Teflon / +Latex - Milled / +Sawed -Without / +With Membrane Strain, +25 microstrain -Water / +Air Time, min Temperature, +0.5 C -10 -8 -6 -4 -2 0 2 4 6 8 10 Change in Deformation Standard Error, Percent Figure 9. Effect of statistically significant ruggedness factors on the deformation standard error. agree with one another. During Phase II of this project a the data from the sawed ends are more variable in the un- maximum deformation uniformity of 20 percent was associ- confined tests at 20C and 40C. Thus, the effects of the ated with good quality data (11). For the deformation uni- ruggedness factors on the deformation uniformity are small formity, only the temperature and end condition were found and not consistent. to be statistically significant. Figure 10 shows the effect of these two factors on the deformation uniformity. The tem- 2.2.2.4 Phase Uniformity perature effect is small considering the allowable value of 20 percent for good quality data. The end condition effect The phase uniformity is a measure of how close the indi- is larger, but not consistent over the temperature ranges. vidual phase angle measurements made on a sample agree For unconfined tests at 4C and confined tests at 40C, the with one another. During Phase II of this project a maximum data from milled ends are more variable. On the other hand, phase uniformity of 3 degrees was associated with good quality Confined 40 C Confinement, +2% 40 C 20 C 4C -Teflon / +Latex - Milled / +Sawed -Without / +With Membrane Strain, +25 microstrain -Water / +Air Time, min Temperature, +0.5 C -20 -15 -10 -5 0 5 10 15 20 Change in Deformation Uniformity, Percent Figure 10. Effect of statistically significant ruggedness factors on the deformation uniformity.