The National Academies Press

Currently Skimming:

Pages 74-102

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 74... ... 74 Experiment 1: Effect of Increased P-200 Content Introduction As stated earlier in the Work Plan section, the original plan was to modify the Georgia design by adding baghouse fines (BHF) to the mixture and therefore increase the P-200 material. Read the entire page →
From page 75... ... Part 2 75 Mixture Type Georgia Good South Carolina Poor Mixture Designation Control +2%BHF +4%BHF Control +2%BHF +4%BHF Aggregate Type Granite Asphalt Type PG 76-22 Binder Modifier 2.5% SBS Polymer Anti-strip 0.5% by weight of binder Fiber, % 0.4 0.3 AC, % 6.0 Total P-200, % 2.0 3.9 6.0 1.7 3.7 5.6 Table 41. Experiment 1 mix design components. Read the entire page →
From page 76... ... 76 Performance-Based Mix Design of Porous Friction Courses The CoreLok air voids of the mixtures (Figure 60) did decrease to a point with added BHF. Read the entire page →
From page 77... ... Part 2 77 Effect on Film Thickness The film thickness of the designs did significantly decrease with the added BHF (Figure 61) Read the entire page →
From page 78... ... 78 Performance-Based Mix Design of Porous Friction Courses with the increased BHF. As seen in Table 45, the Georgia mixes with +2BHF and +4BHF at 5.0% AC had comparable stone loss to the mix at 6.0% AC but without added BHF. Read the entire page →
From page 79... ... Part 2 79 BHF was statistically different from the South Carolina JMF Control Table 46(B) Read the entire page →
From page 80... ... 80 Performance-Based Mix Design of Porous Friction Courses Permeability As discussed in Part 1, there appears to be a direct correlation between air void content and permeability of the PFC specimens. The increased P-200 causes the air void content of the specimens to decrease; therefore, it was expected that the permeability of the specimens would also decrease. Read the entire page →
From page 81... ... Part 2 81 permeability at other asphalt contents. An ANOVA of the results indicates a significant difference (p-value = 0.000) Read the entire page →
From page 82... ... 82 Performance-Based Mix Design of Porous Friction Courses improvement was observed with the 4.0% BHF, specimens based on the HWTT rut depths and RRI values. Moisture Susceptibility Testing The testing for TSR in this experiment was critical. Read the entire page →
From page 83... ... Part 2 83 to ensure passing results. The improvement in performance of the mixture should offset the additional cost of the change in dosage or type of anti-strip. Read the entire page →
From page 84... ... 84 Performance-Based Mix Design of Porous Friction Courses prior to reaching the 93% load reduction and therefore had to be extrapolated. An outlier in both the Georgia Control and Georgia +2BHF designs was observed. Read the entire page →
From page 85... ... Part 2 85 I-FIT Results The I-FIT results for the mix designs with the increased P-200 can be found in Figure 68 through Figure 70. As previously analyzed, the peak load, Gf, and FI of each mix was calculated and summarized. Read the entire page →
From page 86... ... 86 Performance-Based Mix Design of Porous Friction Courses 1.694 1.973 1.892 1.263 1.472 1.592 0.000 0.500 1.000 1.500 2.000 2.500 Av er ag e Pe ak L oa d (k N ) Georgia SBS Control Georgia +2BHF Georgia +4BHF South Carolina SSS Control South Carolina +2BHF South Carolina +4BHF Figure 68. Read the entire page →
From page 87... ... Part 2 87 The ANOVA (α = 0.05) showed that some of the mixtures were statistically differvent when comparing peak load and FI (Table 56) Read the entire page →
From page 88... ... 88 Performance-Based Mix Design of Porous Friction Courses trend of increased P-200 and peak load was linear for each of the designs. There were two outliers removed from the data (1 each from Georgia Control and Georgia +2BHF) Read the entire page →
From page 89... ... Part 2 89 The Gf of both the South Carolina and Georgia designs showed no statistical improvement by increasing the P-200 for each mixture (Figure 72) Read the entire page →
From page 90... ... 90 Performance-Based Mix Design of Porous Friction Courses alone would be sufficient to prevent draindown, and (2) to see if the fiber had an impact on the raveling or cracking potential of the mixture. Read the entire page →
From page 91... ... Part 2 91 Mix ID Total AC (%) Fiber (%) Read the entire page →
From page 92... ... 92 Performance-Based Mix Design of Porous Friction Courses Binder and Fiber Effect on Cantabro Results The Cantabro data showed that the designs without fiber performed better than the design with fiber. This seems to indicate that with the use of modified binders, fiber stabilizers may not be needed. Read the entire page →
From page 93... ... Part 2 93 Binder Effect on Permeability The permeability summary can be seen in Table 66, while a graphical depiction of the results is shown in Figure 76. The Control and SBS had similar permeability results, which may indicate that the fiber had no effect on the permeability of the specimens. Read the entire page →
From page 94... ... 94 Performance-Based Mix Design of Porous Friction Courses 80 79 33 37 0 10 20 30 40 50 60 70 80 90 100 Georgia Control Georgia PG 76-22 SBS Georgia PG 76-22 GTR Georgia PG 82-22 SBS Av er ag e Pe rm ea bi lit y (k ) m et er /d ay Figure 76. Read the entire page →
From page 95... ... Part 2 95 Effect of Binder Type on Moisture Susceptibility The TSR summary results are presented in Table 68. The unconditioned strengths dropped slightly for all of the designs with binder modification, but according to the ANOVA in Table 69 there is not a statistical difference between the unconditioned strengths. Read the entire page →
From page 96... ... 96 Performance-Based Mix Design of Porous Friction Courses An ANOVA was conducted on both the peak load and cycles to failure data. Both sets of analysis have goodness of fit values greater than 90%, which indicates that the models show a good fit with the data. Read the entire page →
From page 97... ... Part 2 97 provides greater elastic recovery. The cracking resistance of the GTR as measured by cycles to failure is significantly less than that of the polymer. Read the entire page →
From page 98... ... 98 Performance-Based Mix Design of Porous Friction Courses with the binder modifications over the Control, but the designs were not statistically different except for the HiMA design (Figure 80 and Table 75) Read the entire page →
From page 99... ... Part 2 99 1,828 2,034 2,178 2,475 0 500 1000 1500 2000 2500 3000 3500 Georgia Control Georgia PG 7622 SBS Georgia PG 7622 GTR Georgia PG 8222 SBS Av er ag e Fr ac tu re E ne rg y (J /m 2) Figure 80. Read the entire page →
From page 100... ... 100 Performance-Based Mix Design of Porous Friction Courses 3.111 3.302 3.110 2.413 0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 4.000 Georgia SBS Control Georgia PG 76-22 SBS Georgia PG 76-22 GTR Georgia PG 82-22 SBS Av er ag e Pe ak L oa d (k N ) Figure 82. Read the entire page →
From page 101... ... Part 2 101 the machine had to be manually stopped. Since the specimens did not reach the 0.1 kN cutoff, all of the area under the curve was not attainable. Read the entire page →
From page 102... ... 102 Performance-Based Mix Design of Porous Friction Courses Mix ID NMAS (mm) Read the entire page →

From page 74...

... 74 Experiment 1: Effect of Increased P-200 Content Introduction As stated earlier in the Work Plan section, the original plan was to modify the Georgia design by adding baghouse fines (BHF) to the mixture and therefore increase the P-200 material.