Ruggedness of Laboratory Tests for Asphalt Mixture Cracking Resistance (2022) / Chapter Skim
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Pages 91-99
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91 Introduction The development of a test standard involves many steps. Ruggedness testing is a crucial step of the development and must be a part of the validation phase.
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92 Ruggedness of Laboratory Tests for Asphalt Mixture Cracking Resistance Recommended Cracking Tests for Field Validation One of the tasks of NCHRP 09-57A is to recommend the cracking tests for field validation, with the goal of the tests being used in three major applications: asphalt mix design, QC/QA, and pavement structural design. When recommending cracking tests for field validation, the research team considered seven factors.
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Cracking Test Recommendations for Field Validation 93 Scenario 1: Sufficient Funding Scenario 2: Constrained Funding Scenario 3: Extremely Constrained Funding 1.
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94 Ruggedness of Laboratory Tests for Asphalt Mixture Cracking Resistance Cracking Test 12.5-mm SMA 12.5-mm Superpave 9.5-mm Superpave Sensitivity ASTM D7313: DCT-Gf 775 397 334 12.5-mm SMA has much better cracking resistance than the two Superpave mixtures; the two Superpave mixtures have very similar cracking resistance. AASHTO TP 105: SCB-LT-Gf 575 312 273 AASHTO TP 124: SCB-FI 31.7 4.7 4.7 ASTM D8225: IDEAL-CT 608 71 75 AASHTO T 321: BBF-Na 601497 66267 29779 Tex-248-F: OT-N 970 67 66 Tex-248-F: OT-CRI 93.5 39.4 41.9 Tex-248-F: OT-CPR 0.3 0.7 0.7 UF-IDT-ER 2.2 1.4 2.0 SMA is better.
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Cracking Test Recommendations for Field Validation 95 Figure 49. Cracking test adoption (West, 2020)
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96 Ruggedness of Laboratory Tests for Asphalt Mixture Cracking Resistance – AASHTO TP 105: SCB-LT is a complex test. The test has a nine-step loading process, including eight steps of preloading, before actually starting a CMOD-controlled loading, as shown in Figure 26.
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Cracking Test Recommendations for Field Validation 97 (a) Taylor (2018)
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98 Ruggedness of Laboratory Tests for Asphalt Mixture Cracking Resistance In addition, in extremely constrained conditions, the research team recommends that SCB-Jc be removed from field validation. Jc is an indication of the amount of energy required to propagate a crack (or a preexisting flaw)
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Cracking Test Recommendations for Field Validation 99 Summary This chapter discussed all 10 cracking tests according to various criteria. A one-page summary for each test is provided in Appendix J
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