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OCR for page 86
86 APPENDIX NCHRP Project 9-35 Aggregate Specification Survey 1) Do you use the sand equivalent test (AASHTO T176) to identify clay-like particles in fine aggregate? If yes, do the minimum specification values as a function of design traffic in your specifications match those in AASHTO MP2? If no, what test, if any, do you use? If you use alternate test methods or specification values, what research or experience prompted this change? 2) Do you use the fine aggregate angularity test (AASHTO T304) to identify rounded fine aggregates? If yes, do the minimum specification values as a function of design traffic and depth from the pavement surface in your specifications match those in AASHTO MP2? If no, what test, if any, do you use? If you use alternate test methods or specification values, what research or experience prompted this change? Do you limit the percentage of natural sand in a mix by specification?

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87 3) Do you use the coarse aggregate angularity test (ASTM D5821) to identify the number of fractured faces on coarse aggregates? If yes, do the minimum specification values as a function of design traffic and depth from the pavement surface in your specifications match those in AASHTO MP2? If ASTM D5821 is specified, do you specify it on all coarse aggregates, or only on gravel sources? If ASTM D5821 is not specified, what test, if any, do you use? If you use alternate test methods or specification values, what research or experience prompted this change? 4) Do you specify the flat and elongated particle test (ASTM D 4791) to identify misshapen coarse aggregate particles? If yes, do the minimum specification values as a function of design traffic in your specifications match those in AASHTO MP2? In addition to the 51 maximum-to-minimum dimension specified in AASHTO MP2, do you have any additional specification requirements--for example, 31, 21, flat particles, or elongated particles? If you do not specify ASTM D4791, what test, if any, do you use? If you use alternate test methods or specification values, what research or experience prompted this change?

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88 5) Do you use LA abrasion (AASHTO T96) as a source property to identify aggregate hardness and polish resistance? If you do not use the LA abrasion test, what test if any do you use? (We will retrieve your specification levels from the specifications you provide.) 6) Do you use sodium or magnesium sulfate soundness (AASHTO T104) as a source property for freeze-thaw durability? Do you allow sodium sulfate, magnesium sulfate, or both? If you allow both, are your specification requirements the same for both sodium and magnesium sulfate soundness? If you do not use sodium or magnesium soundness, what test, if any, do you use to qualify aggregate durability? (We will retrieve your specification levels from the specifications you provide.) 7) Are there any other source properties that you specify (please list)? 8) Have you modified the Superpave gradation bands from those shown in AASHTO MP2? If you have altered the gradation bands, why was this done?

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89 9) Do you differentiate between coarse and fine Superpave mixes? If so, what do you use to differentiate them? Do you have different density specifications for coarse and fine Superpave mixes? Do you have permeability specifications that are a function of gradation? Do you vary recommended lift thickness as a function of gradation or nominal maximum aggregate size? What are your recommended ranges for lift thickness to nominal maximum aggregate size? (If they are in your specifications that you have sent, please indicate.) 10) What aggregate specific gravity do you use during design to calculate VMA? a) Apparent b) Effective c) Bulk 11) Who determines the aggregate specific gravities used for design? a) Contractor b) Agency c) Other ________________________________ 12) What aggregate specific gravity is used during production to calculate VMA and how is it determined? 13) Do your minimum VMA requirements match those found in AASHTO MP2?

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90 14) Are your laboratory compaction efforts as a function of traffic level the same as those specified in AASHTO MP2? 15) What time interval do you use to calculate design ESALs? 16) Please identify your most common aggregate types--for example, granite, limestone, gravel. 17) Do you import aggregate from out of state to meet Superpave aggregate properties? If so, what aggregate properties are difficult to meet? 18) Do you have any problematic aggregate sources or types? If so, please identify the aggregate type and typical problem. 19) Is there any ongoing or recently completed research you are sponsoring on aggregate properties relevant to this study? If so, who is conducting this research and where may we obtain copies of reports? 20) Do you have any recommendations for additional aggregate research? 21) Do you have any additional comments or recommendations for this research effort?