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From page 36... ... 36 This chapter presents and discusses most of the technical effort of NCHRP 09-59. Immediately after this introduction, the results of the laboratory testing and analysis of the resulting data are presented. Read the entire page →
From page 37... ... Findings and Applications 37 Binder ID k1 k2 r2 (%) Read the entire page →
From page 38... ... 38 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures 2. The fatigue life curves at 10°C were closer together compared with those at 20°C, indicating that the fatigue lives of these mixes became less different as the test temperature decreased. Read the entire page →
From page 39... ... Findings and Applications 39 Mixture Fatigue Testing -- GFTAB Analysis In applying the GFTAB model to flexural fatigue data, statistical methods were applied to determine FFPR values as outlined in Chapter 2 and discussed in detail in Appendix D Table 9 is a summary of the non-linear least squares analysis of the flexural fatigue data using the GFTAB model. Read the entire page →
From page 40... ... 40 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Figure 17 is a plot showing observed and predicted cycles to failure, coded for data source (NCHRP 09-59 or SHRP) Read the entire page →
From page 41... ... Findings and Applications 41 0.0 0.5 1.0 1.5 2.0 2.5 A B C I J K M O P AAA AAB AAC AAD AAF AAG AAK AAM Flexural Fatigue FFPR Bi nd er C od e 0.0 0.5 1.0 1.5 2.0 A B C D E F G H I J K L M N O P Uniaxial Fatigue FFPR As ph al t B in de r C od e Figure 18. é 2s Confidence limits for flexural fatigue FFPR values. Read the entire page →
From page 42... ... 42 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures R² = 75% 0.40 0.60 0.80 1.00 1.20 0.40 0.60 0.80 1.00 1.20 FF PR fr om U ni ax ia l T es tin g FFPR from Flexural Fatigue Figure 20. Comparison of FFPR from flexural fatigue testing with FFPR from uniaxial fatigue testing. Read the entire page →
From page 43... ... Findings and Applications 43 R² = 83% 0.0 0.5 1.0 1.5 2.0 2.5 0.0 1.0 2.0 3.0 4.0 M ix tu re F ati gu e FF PR R-value SHRP (non-modified) BBF non-modified BBF polymer modified Uniaxial non-modified Uniaxial polymer modified R² = 81% R² = 96% 0.0 0.5 1.0 1.5 2.0 2.5 0.0 1.0 2.0 3.0 4.0 SD EN T Ex t. Read the entire page →
From page 44... ... 44 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Furthermore, it appears to be valid for both polymer-modified and non-modified binders. This finding initially puzzled the research team, but they now believe that the effect of polymer modification on mixture fatigue in highly aged mixtures at intermediate to low temperatures is reduced compared with the effect in binder tests on lightly to moderately aged binders at intermediate temperatures. Read the entire page →
From page 45... ... Findings and Applications 45 As mentioned, there are several reasons for this but the most important is perhaps the relatively slow loading rate used in the SDENT test compared with mixture fatigue loading. The resulting relatively low binder stiffness in the SDENT test seems to improve the performance of most polymers used in the NCHRP 09-59 binders. Read the entire page →
From page 46... ... 46 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures R² = 68% 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 M ix tu re F ati gu e FF PR LAS FFPR SHRP (non-modified) BBF non-modified BBF polymer modified Uniaxial non-modified Uniaxial polymer modified R² = 73% 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 2.0 2.5 3.0 3.5 M ix tu re F ati gu e FF PR R-value Uniaxial non-modified Uniaxial polymer modified R² = 38% 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0.0 0.5 1.0 1.5 M ix tu re F ati gu e FF PR SDENT Extension FFPR Uniaxial non-modified Uniaxial polymer modified Figure 25. Read the entire page →
From page 47... ... Findings and Applications 47 fatigue as a function of R-value; the r2 value in this case is moderate at 66%. The final plot in this series, Figure 29, shows flexural fatigue FFPR as a function of SDENT FFPR. Read the entire page →
From page 48... ... 48 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Healing Experiment Results of the healing experiment are shown in Figures 30 through 32. Figure 30 shows healing ratio as a function of binder phase angle at 0.13 rad/s; this frequency represents an approximate equivalent to the recovery time for the pulse loading. Read the entire page →
From page 49... ... Findings and Applications 49 "Validating an Endurance Limit for HMA Pavements: Laboratory Experiment and Algorithm Development," found a relationship between mixture and binder stiffness and healing and endurance limit, in which increasing healing is associated with decreasing binder stiffness (see Witczak et al. Read the entire page →
From page 50... ... 50 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures with healing. This is probably because of the more complex rheology and chemistry of polymermodified binders. Read the entire page →
From page 51... ... Findings and Applications 51 A layered elastic analysis was performed on two simple hypothetical pavement systems. The "thin" pavement structure consisted of 100-mm of asphalt concrete over a 200-mm subbase with a modulus of 150 MPa, resting on a subgrade with a modulus of 80 MPa. Read the entire page →
From page 52... ... 52 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Layered Elastic Analysis and Potential Fatigue Specification Parameters Is there a rheological parameter that relates well to the fatigue life of a pavement? Examples are the current binder fatigue specification parameter, \|G* Read the entire page →
From page 53... ... Findings and Applications 53 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 Cy cl es to fa ilu re 2 < R < 2.5 2.5 < R < 3 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 \|G* \| sin δ, kPa 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 Cy cl es to fa ilu re 2 < R < 2.5 2.5 < R < 3 GRP, kPa 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 Cy cl es to fa ilu re 2 < R < 2.5 2.5 < R < 3 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 Binder \|G* Read the entire page →
From page 54... ... 54 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 Cy cl es to fa ilu re 2 < R < 2.5 2.5 < R < 3 \|G* \| sin δ, kPa 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 Cy cl es to fa ilu re 2 < R < 2.5 2.5 < R < 3 GRP, kPa 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 Cy cl es to fa ilu re Binder \|G* Read the entire page →
From page 55... ... Findings and Applications 55 In the previous discussion, the terms "thin" and "thick" pavement refer to the specific structures used in the layered elastic analysis: "thin" meaning the pavement with 100 mm of bound material over a 200-mm subbase, and "thick" meaning the pavement with 200 mm of bound material over a 300-mm subbase. In the remainder of this report, these terms are for the most part used in a more general sense: "thin" pavements are those in which the strains are relatively high and mostly controlled by the pavement subgrade, while "thick" pavements are those in which the strains are relatively low and controlled by the stiffness of the bound layers. Read the entire page →
From page 56... ... 56 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures and a pavement thickness (bound material) increased by 20 mm. Read the entire page →
From page 57... ... Findings and Applications 57 selected new fatigue parameter. Significant evidence has also shown that fatigue performance is related to R-value and that an allowable range for R-value would also help ensure good fatigue performance. Read the entire page →
From page 58... ... 58 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures relaxing R-value requirements for polymer-modified binders. Another reason for maintaining the same R-value limits for polymer-modified binders is that these materials are expected to exhibit superior performance -- if the maximum R-value is relaxed for polymer-modified binders, some materials might exhibit no better fatigue resistance than non-modified binders. Read the entire page →
From page 59... ... Findings and Applications 59 R² = 77% 0.1 1.0 10.0 100.0 1.E+03 1.E+04 1.E+05 Fa tig ue S tr ai n Ca pa ci ty , % \|G* \| sin δ, kPa R² = 74% 0 5 10 15 20 0 20 40 60 80 100 FS C, % SDENT Extension, mm Figure 47. Read the entire page →
From page 60... ... 60 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Two significant problems in the current binder fatigue specification have been identified in this report to this point: (1) the current parameter, \|G* Read the entire page →
From page 61... ... Findings and Applications 61 test temperature and average pavement temperature; the test temperature is too high for harder binder grades and too low for softer grades. Figure 51 shows the relationship for the proposed system. Read the entire page →
From page 62... ... 62 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures proposed system would at least partially correct this problem. A better match between fatigue test temperature and average test temperature would probably involve a more complicated system and a significant increase in the number of grades producers would have to supply. Read the entire page →
From page 63... ... Findings and Applications 63 Field Validation Sites Three sets of test pavements were included in validation testing: (1) four test sections on US-93 about 50 miles north of Wikieup, Arizona; (2) Read the entire page →
From page 64... ... 64 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures Project Age at Survey years Section Code Fatigue Cracking AZ US-93 near Wikieup 11 1-1 7.9 m 1-2 17.8 m 1-3 64.7 m 1-4 66.1 m MN US-112 near Rochester/ Olmsted Co. 8 1-2 0.8 m 1-3 18.8 m 1-4 39.2 m 1-5 0 m NCAT test track, Auburn, AL 3 N1 22.5% N8 17.0% S5 0% S6 0% Table 17. Read the entire page →
From page 65... ... Findings and Applications 65 0 5 10 15 20 25 0 20 40 60 80 100 0 50,000 100,000 Cr ac ki ng , % a re a Cr ac ki ng , s qu ar e m et er \|G* Read the entire page →
From page 66... ... 66 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures the relationship for the Arizona and NCAT test sites is reversed from what is expected and from that observed for the Minnesota test site. For the Arizona and NCAT test sections, cracking decreases with increasing R-value rather than increasing. Read the entire page →
From page 67... ... Findings and Applications 67 0 5 10 15 20 25 0 20 40 60 80 100 0 10,000 20,000 30,000 40,000 Cr ac ki ng , % a re a Cr ac ki ng , s qu ar e m et er AZ (left) , 78% MN/MTE (left) Read the entire page →
From page 68... ... 68 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures fatigue performance is mostly a function of binder modulus, with R-value having a secondary effect. Modulus is mostly a function of temperature, so if the fatigue test temperature is not selected consistently, the resulting parameter values will not be effective in controlling fatigue performance. Read the entire page →
From page 69... ... Findings and Applications 69 R² = 94% 0 20 40 60 80 100 0 2,000 4,000 6,000 8,000 Pe rc en t C ra ck ed GRP, kPa R² = 91% 0 20 40 60 80 100 0 5,000 10,000 15,000 Pe rc en t C ra ck ed \|G* Read the entire page →
From page 70... ... 70 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures 8,000 kPa to account for the more severe aging and for where the various binders appear on this plot. Of the seven binders with estimated good fatigue performance, six pass the proposed specification. Read the entire page →
From page 71... ... Findings and Applications 71 However, this standard envelope varies significantly among different binders. A fundamental question addressed in NCHRP 09-59 is which test or tests are good indicators of this inherent strain tolerance. Read the entire page →
From page 72... ... 72 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures A serious concern -- probably even more significant than the concern with \|G* \| sin δ -- is the ineffective way the current specification addresses fatigue test temperature. Read the entire page →
From page 73... ... Findings and Applications 73 As discussed previously in this report, parameters other than R-value exert a similar control over binder rheology. These include ΔTc and BBR stiffness at m = 0.30 (S (0.3) Read the entire page →
From page 74... ... 74 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures modified, healing increases with increasing phase angle. This means that healing will increase with increasing temperature and decreasing values of R or increasingly positive values of ΔTc. Read the entire page →
From page 75... ... Findings and Applications 75 of service, pavements made with polymer-modified binders might exhibit significantly better fatigue performance than those made with non-modified binders. Even if this benefit were to disappear after 5 to 10 years of service, the initial improvement in performance should still result in substantially longer pavement life when polymer-modified binders are used. Read the entire page →
From page 76... ... 76 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures polymer-modified binders evaluated in NCHRP 09-59 -- that is, even though their FFPR values are not much different from the non-modified binders, their expected fatigue performance as indicated by GRP is generally better than the non-modified binders. This expected performance is clear from Figure 65, which shows GRP at the proposed fatigue test temperature and 10 rad/s for the 16 NCHRP 09-59 binders. Read the entire page →
From page 77... ... Findings and Applications 77 than commonly used in mixture fatigue tests. Most mixture fatigue tests done during SHRP, for example, involved conditions corresponding to binder modulus values ranging from about 3 to 30 MPa. Read the entire page →

From page 36...

... 36 This chapter presents and discusses most of the technical effort of NCHRP 09-59. Immediately after this introduction, the results of the laboratory testing and analysis of the resulting data are presented.