Annotated Literature Review for NCHRP Report 640 (2009) / Chapter Skim
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97 1.22.7 Performance No specific performance measures were given. 1.22.8 Structural Design No specifics on inclusion with structural design were given.
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98 Table 53: Gradations Used Percent Passing Sieve Size Original FHWA Gradation Gradation Similar to FHWA Used New Gradation #1 New Gradation #2 New Gradation #3 19 mm -- - 100 100 100 100 12.5 mm 100 95 95 95 95 9.5 mm 95-100 65 65 65 65 4.75 mm 30-50 40 30 25 15 2.36 mm 5-15 12 7 7 7 0.075 mm 2-5 4 3 3 3 The FHWA gradation has 40 percent material passing the 4.75 mm sieve, and the coarsest of the other three gradations has 15 percent material passing the 4.75 mm sieve. The coarsest gradation is very similar to the gradation that is being used by many states reporting good experience at the time with OGFC mixes.
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99 Table 54: Summary of Mix Volumetric Properties Compacted OGFC Mix Gradation (% passing 4.75 mm sieve) Asphalt Content TMD*
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100 mixes were then prepared with six different types of binder (Table 55)
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101 Table 57: Abrasion Loss (Aged Samples) for Mixes with Different Types of Binder Duncan Grouping Mean (%)
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102 Again, both polymer-modified binder and fiber should be most effective especially in cold climates with freeze/thaw cycles. To provide a clear understanding of the methods used by the authors, the following paragraphs describe the various tests utilized in the research.
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103 aged specimens should not exceed 30 percent, while no individual result should exceed 50 percent. Raveling of the OGFC may take place due to stripping in the mix, especially from freeze and thaw cycles in northern tier states with cold climates.
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104 Selection of the design gradation entails blending selected aggregate stockpiles to produce three trial blends. It was suggested that the three trial gradations fall along the coarse and fine limits of the gradation range along with one falling in the middle.
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105 Step 4. Evaluate Mix for Moisture Susceptibility The mix designed with Step 1 through 3 should be evaluated for moisture susceptibility using the modified Lottman method (AASHTO T283)
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106 Table 58: Laboratory Test Results for the Six OGFC Mixes (6) Test D D16R DM DC DP DCP Percent passing 19.0 mm 100 100 100 100 100 100 Percent passing 12.5 mm 99 99 99 99 99 99 Percent passing 9.5 mm 75 75 75 75 75 75 Percent passing 4.75 mm 18 18 18 18 18 18 Percent passing 2.36 mm 8 8 8 8 8 8 Percent passing 0.075 mm 2 2 2 2 2 2 Percent Asphalt Binder of Total Mix % AC 6.0 6.6 6.3 6.4 6.2 6.4 Other Test Data Cantabro (% Wear)
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107 Based on Table 59, five of the produced mixes were finer than the JMF gradation on the 4.75 mm sieve. Only one gradation (DM)
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108 All six test sections had experienced some coarse aggregate popout. The D16R section appeared to have the most while the DC, DM, and DP sections all had a very low amount.
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