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From page 123... ... D-1 Analysis of Mixture Fatigue and Binder Test Data Introduction One of the biggest challenges during NCHRP 09-59 was developing methods to effectively compare mixture fatigue performance to specific binder test data. There are a few problems in making such comparisons, especially when the comparison involves performance of actual pavements. Read the entire page →
From page 124... ... D-2 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Modeling Fatigue in Asphalt Concrete There are two general types of fatigue laws. The first and most common expresses fatigue life, typically as cycles to failure, as a function of stress or strain, modulus, and one or more volumetric factors such as air void content or voids filled with asphalt. Read the entire page →
From page 125... ... Analysis of Mixture Fatigue and Binder Test Data D-3 A New Approach to Analyzing Asphalt Concrete Fatigue Damage None of the available fatigue models discussed has proved useful in correlating binder test data to mixture fatigue performance. Standard laboratory fatigue tests are often not even particularly good indicators of field performance. Read the entire page →
From page 126... ... D-4 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures where R = Christensen-Anderson R-value (rheologic index) Read the entire page →
From page 127... ... Analysis of Mixture Fatigue and Binder Test Data D-5 In this case, the calculation of damage can be done by breaking up the loading history into numerous small segments with approximately equal strain and calculating and summing the damage according to Equation D-7. Failure will occur when D = 1, which leads to the following equation for calculating FSC for a laboratory fatigue test in which strain is not constant (where Nf is the total loading cycles to failure) Read the entire page →
From page 128... ... D-6 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures asphalts vary from the average or typical failure envelope. For instance, many polymer-modified binders exhibit FSC values substantially higher than typical non-modified binders. Read the entire page →
From page 129... ... Analysis of Mixture Fatigue and Binder Test Data D-7 Analysis of Mixture Fatigue and Binder Test Data Materials and Test Methods Asphalt Binders Sixteen asphalt binders were selected for testing as part of NCHRP 09-59. These covered a wide range of binder grades and types. Read the entire page →
From page 130... ... D-8 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures may not appear overly complicated, developing and fine tuning this analysis was difficult and time consuming -- many different approaches were tried and evaluated before settling on the approach described here. The first step in this analysis was to analyze the mixture flexural fatigue data. Read the entire page →
From page 131... ... Analysis of Mixture Fatigue and Binder Test Data D-9 Vbe = mixture effective binder content, volume (%) ; k1 = fatigue exponent coefficient of 2; εt = mixture maximum tensile strain (%) Read the entire page →
From page 132... ... D-10 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures deviation, t-values, and p-values are also included in these tables. Note that the standard deviation and related statistics for asphalt AAM could not be determined because of restrictions on degrees of freedom in the model. Read the entire page →
From page 133... ... Analysis of Mixture Fatigue and Binder Test Data D-11 loose-mix aging used in NCHRP 09-59. Figure D-4 is a plot showing the ± 2s confidence limits for all 16 binders included in this analysis. Read the entire page →
From page 134... ... D-12 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures limited to modulus values represented in the NCHRP 09-59 data used in the analysis. There is good agreement between the GFTAB failure envelope and the other two shown in Figure D-6 -- the minor discrepancy is easily explained by differences between the simple state of stress existing in binder tests and the complex, triaxial stress conditions existing in a mixture subject to fatigue. Read the entire page →
From page 135... ... Analysis of Mixture Fatigue and Binder Test Data D-13 In this equation, the damage is summed up incrementally and then used to calculate the fatigue strain capacity for the individual binder (Equation D-6) , and then divided by FSC* Read the entire page →
From page 136... ... D-14 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures analysis. Figure D-8 shows the ±2s confidence limits for FFPR values as determined from uniaxial fatigue data; the results are expressed in arithmetic terms, rather than the log transform, to make them easier to understand and interpret. Read the entire page →
From page 137... ... Analysis of Mixture Fatigue and Binder Test Data D-15 Analysis of Binder Test Data The R-values for the binders were calculated from LAS data at 10 Hz using an equation based on the Christensen-Anderson model and assuming a glassy modulus of 1 GPa (Christensen and Anderson, 1992) Read the entire page →
From page 138... ... D-16 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Analysis of the SDENT data is complicated by the fact that the heavily notched specimen cannot be analyzed as if it were a tension test, using calculated stresses, strains, and modulus. The procedure used instead relied on comparing measured specimen extension and initial specimen stiffness. Read the entire page →
From page 139... ... Analysis of Mixture Fatigue and Binder Test Data D-17 Binder Code Mix FFPR/ Flexural Fatigue Mix FFPR/ Uniaxial Fatigue R-Value Binder FFPR/ SDENT Extension Binder FFPR/ LAS Test A 0.577 0.618 3.140 0.581 0.559 B 0.721 0.742 2.440 0.839 0.956 C 1.024 0.959 2.280 1.075 0.934 D 1.036 2.100 0.934 0.880 E 0.617 2.910 0.759 0.686 F 0.690 2.490 0.773 0.800 G 0.747 2.450 1.313 0.804 H 0.750 2.640 0.978 0.746 I 1.007 1.004 2.100 0.941 0.944 J 0.839 0.834 2.320 1.123 0.900 K 0.787 0.767 2.650 0.739 0.720 L 0.367 3.060 0.582 0.670 M 0.915 0.659 2.560 1.016 0.955 N 0.534 3.210 0.629 0.652 O 1.128 0.859 2.290 1.106 0.973 P 0.645 0.569 2.580 0.812 0.781 AAA 1.108 1.730 1.248 1.142 AAB 0.952 2.080 0.960 0.921 AAC 1.047 2.010 1.048 0.939 AAD 1.146 1.770 1.057 1.200 AAF 1.339 1.930 1.167 1.014 AAG 2.008 1.350 1.545 1.242 AAK 1.443 1.780 1.108 1.170 AAM 0.810 2.440 0.759 0.894 Est. Read the entire page →
From page 140... ... D-18 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures R² = 63% 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 M ix tu re F ati gu e FF PR SDENT Extension FFPR SHRP (non-modified) BBF non-modified BBF polymer modified Uniaxial non-modified Uniaxial polymer modified R² = 98% R² = 73% R² = 56% R² = 91% 5 10 15 20 25 1.E+05 1.E+06 1.E+07 D EN T Ex te ns io n, m m \|G* Read the entire page →
From page 141... ... Analysis of Mixture Fatigue and Binder Test Data D-19 relationship for non-polymer-modified binders. As discussed, the shift in the polymer-modified data is probably because the relatively slow loading rate in the SDENT results in enhanced polymer effectiveness compared to the mixture fatigue tests. Read the entire page →
From page 142... ... D-20 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Figure D-14 shows the relationship between mixture fatigue FFPR values and LAS FFPR. The r2 value for this relationship, like Figure D-12, is only moderate (68%) Read the entire page →
From page 143... ... Analysis of Mixture Fatigue and Binder Test Data D-21 R-value and strain tolerance as indicated by FFPR suggests one reason these binders tend to be prone to excessive cracking -- they are excessively brittle. As discussed elsewhere in this report, there are at least two other reasons these binders show poor field performance: (1) Read the entire page →
From page 144... ... D-22 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Kutner, M Read the entire page →

From page 123...

... D-1 Analysis of Mixture Fatigue and Binder Test Data Introduction One of the biggest challenges during NCHRP 09-59 was developing methods to effectively compare mixture fatigue performance to specific binder test data. There are a few problems in making such comparisons, especially when the comparison involves performance of actual pavements.