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From page 34... ... 34 5.1 Sensitivity Experiments The results of the sensitivity study were analyzed using the linear regression method. For each combination of variables (furnace type, test temperature, air flow, sample mass, and asphalt content) Read the entire page →
From page 35... ... 35 Table 26. Significance of asphalt content correction factor test parameters based on p-values – sensitivity study – Experiment 1 by mixture. Read the entire page →
From page 36... ... 36 From Table 26 and Table 27, results for the correction factors are discussed in the following. Read the entire page →
From page 37... ... 37 significant for 10 of 12 combinations, air flow for seven of 12 combinations, and asphalt content for eight of 12 combinations. Sample mass was found significant only for one combination, Mix 2 for the Troxler furnace. Read the entire page →
From page 38... ... Ignition Unit Variable Levels Average Correction Factor (%) Statistically Significant (Y/N) Read the entire page →
From page 39... ... 39 Table 29 through Table 32 indicate whether the results are statistically significant and practically significant. The analysis of the results for Mix 1 presented in Table 29 indicate the following: • Test temperature (burning profile for the Troxler unit) Read the entire page →
From page 40... ... 40 approximately the same D correction factor, equal to 0.6. For both units, higher temperature resulted in a higher correction factor. Read the entire page →
From page 41... ... 41 0 20 40 60 80 100 120 140 160 Mix 1 Mix 2 Mix 3 Mix 4 Mix 1 Mix 2 Mix 3 Mix 4 800°F 1000°F A ve ra ge T es t Ti m e (m in ) Figure 27. Read the entire page →
From page 42... ... 42 only include the time the samples were inside the furnace, not the time the samples were allowed to cool. Figure 30 and Figure 31 show the average maximum test temperature by mixture type and test temperature for the Thermolyne and Troxler furnaces for testing conducted at 800°F (427°C) Read the entire page →
From page 43... ... 43 Factors 1/2" 3/8" #4 #8 #16 #30 #50 #100 #200 Furnace (Thermolyne, Troxler, Gilson) 0.06 0.09 0.00 0.02 0.05 0.15 0.71 0.99 0.08 Test temp. Read the entire page →
From page 44... ... 44 Based on the analysis results shown in Table 33 through Table 36, the following observations were made regarding the test results: For Mix 1. • Furnace type was found to be significant for six of nine sieve sizes. Read the entire page →
From page 45... ... 45 to be affected by sample mass. This contrasts with the findings for the asphalt correction factors since this particular variable did not affect the asphalt correction factor results. Read the entire page →
From page 46... ... 46 with the exception of #200 sieves for Mixes 1, 2, and 4. Using the average gradation and the blank sample gradations, the approximate aggregate correction factors were determined for each sieve size. Read the entire page →
From page 47... ... 47 the factors with their corresponding p-values; p-values that are less than or equal to 0.10 are shown in bold. Table 42 summarizes the average asphalt correction factors for each significant variable at each level of analysis by mixture. Read the entire page →
From page 48... ... 48 were 1,010, 965, and 1,050°F (543, 518, and 566°C) , respectively. Read the entire page →
From page 49... ... 49 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 La b 1TH La b 2TH La b 3TH La b 4TH La b 5TH La b 6TH La b 7TH La b 8TH La b 9TH La b 10 -T H La b 11 -T H La b 12 -T H La b 13 -T H La b 14 -T H La b 15 -T H La b 16 -T H La b 17 -T H La b 16 -G S La b 18 -G S La b 19 -G S La b 10 -T X La b 20 -T X La b 17 -T X La b 4TX La b 21 -T X La b 22 -T X La b 12 -T X La b 23 -T X Thermolyne Gilson Troxler A sp ha lt C on te nt C F Mix 1 Average=0.11 Min. =-0.66 Max.=0.62 Figure 32. Read the entire page →
From page 50... ... 50 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 La b 1TH La b 2TH La b 3TH La b 4TH La b 5TH La b 6TH La b 7TH La b 8TH La b 9TH La b 10 -T H La b 11 -T H La b 12 -T H La b 13 -T H La b 14 -T H La b 15 -T H La b 16 -T H La b 17 -T H La b 16 -G S La b 18 -G S La b 19 -G S La b 10 -T X La b 20 -T X La b 17 -T X La b 4TX La b 21 -T X La b 22 -T X La b 12 -T X La b 23 -T X Thermolyne Gilson Troxler A sp ha lt C on te nt C F Mix 3 Average=0.92 Min. =0.55 Max.=1.51 Figure 34. Read the entire page →
From page 51... ... 51 Figure 36 shows the average test time by mixture type for Thermolyne (17 units) , Troxler (eight units) Read the entire page →
From page 52... ... 52 0 0.5 1 1.5 2 2.5 3 3.5 4 La b 1TH La b 2TH La b 3TH La b 4TH La b 5TH La b 6TH La b 7TH La b 8TH La b 9TH La b 10 -T H La b 11 -T H La b 12 -T H La b 13 -T H La b 14 -T H La b 15 -T H La b 16 -T H La b 17 -T H La b 16 -G S La b 18 -G S La b 19 -G S La b 10 -T X La b 20 -T X La b 17 -T X La b 22 -T X La b 12 -T X La b 23 -T X Thermolyne Gilson Troxler k St a s cs Mix 2 Crical value =2.23 Figure 38. Within-laboratory k values by laboratory and furnace type – Mix 2 (without extreme outliers) Read the entire page →
From page 53... ... 53 0 0.5 1 1.5 2 2.5 3 La b 1TH La b 2TH La b 3TH La b 4TH La b 5TH La b 6TH La b 7TH La b 8TH La b 9TH La b 10 -T H La b 11 -T H La b 12 -T H La b 13 -T H La b 14 -T H La b 15 -T H La b 16 -T H La b 17 -T H La b 16 -G S La b 18 -G S La b 19 -G S La b 10 -T X La b 20 -T X La b 17 -T X La b 4TX La b 21 -T X La b 22 -T X La b 12 -T X La b 23 -T X Thermolyne Gilson Troxler k St a s cs Mix 3 Crical value =2.22 Figure 39. Within-laboratory h values by laboratory and furnace type – Mix 3. Read the entire page →
From page 54... ... 54 -3 -2 -1 0 1 2 3 4 La b 1TH La b 2TH La b 3TH La b 4TH La b 5TH La b 6TH La b 7TH La b 8TH La b 9TH La b 10 -T H La b 11 -T H La b 12 -T H La b 13 -T H La b 14 -T H La b 15 -T H La b 16 -T H La b 17 -T H La b 16 -G S La b 18 -G S La b 19 -G S La b 10 -T X La b 20 -T X La b 17 -T X La b 22 -T X La b 12 -T X La b 23 -T X Thermolyne Gilson Troxler h St a s cs Mix 1 Crical value =2.62 Crical value =-2.62 Figure 41. Between-laboratory h values by laboratory and furnace type – Mix 1 (without extreme outliers) Read the entire page →
From page 55... ... 55 -3 -2 -1 0 1 2 3 4 La b 1TH La b 2TH La b 3TH La b 4TH La b 5TH La b 6TH La b 7TH La b 8TH La b 9TH La b 10 -T H La b 11 -T H La b 12 -T H La b 13 -T H La b 14 -T H La b 15 -T H La b 16 -T H La b 17 -T H La b 16 -G S La b 18 -G S La b 19 -G S La b 10 -T X La b 20 -T X La b 17 -T X La b 4TX La b 21 -T X La b 22 -T X La b 12 -T X La b 23 -T X Thermolyne Gilson Troxler h St a s cs Mix 3 Crical value =2.63 Crical value =-2.63 Figure 43. Between-laboratory h values by laboratory and furnace type – Mix 3 (without extreme outliers) Read the entire page →
From page 56... ... 56 once for Mix 4, by Lab 16-GS. For Mix 3 and Lab 21-TX, the h value was 2.45; this number closely approached the critical value but did not exceed it. Read the entire page →
From page 57... ... 57 lime is accurately added to a mixture at a consistent rate, then the ignition test should be satisfactory for use, at least for lowmass-loss aggregates. No testing was performed with lime in high-mass-loss aggregates, so it is not certain what the effect of that might be. Read the entire page →
From page 58... ... 58 It is also interesting to note that higher correction factors for a specific mix and unit do not always translate to higher standard deviations when compared to lower correction factor test results for the same mix but a different unit. 5.3 Troubleshooting Outliers from Round-Robin Study NCAT personnel visited the six laboratories identified as outliers to explore the possible causes of the differences in their test results. Read the entire page →
From page 59... ... 59 For the Troxler furnace, the results from the RRS for Mixes 1 and 2 were significantly different from the average correction factors for all laboratories (as presented in Table 48) Read the entire page →
From page 60... ... 60 from Mixes 3 and 4 were tested by NCAT to determine possible causes of the high results. Two replicates of each mixture were first tested without any changes to verify the results from the RRS. Read the entire page →
From page 61... ... 61 The results from the Thermolyne furnace during the RRS were higher than the mean AC content from the other laboratories for Mix 3. During the laboratory visit, several tests were conducted using samples from Mixes 3 and 4. Read the entire page →
From page 62... ... 62 Figure 50. Thermolyne ignition furnace in Lab 16. Read the entire page →
From page 63... ... 63 (538°C) instead of the recommended 1,562°F (850°C) Read the entire page →
From page 64... ... 64 Figure 54. Troxler ignition furnace in Lab 21. Read the entire page →

From page 34...

... 34 5.1 Sensitivity Experiments The results of the sensitivity study were analyzed using the linear regression method. For each combination of variables (furnace type, test temperature, air flow, sample mass, and asphalt content)