Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements (2022)

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56 A P P E N D I X A Survey Questionnaire Dear member of the AASHTO Committee on Materials and Pavements (COMP): The Transportation Research Board, through the National Cooperative Highway Research Program (NCHRP), under the sponsorship of the American Association of State Highway and Transportation Officials (AASHTO), and in cooperation with the Federal Highway Administration (FHWA), is preparing a synthesis on Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements. The objective of this synthesis is to document current practices agencies use to assess and mitigate moisture damage during mix design and acceptance as well as emerging technologies they are exploring. This information will be collected through this survey, an extensive literature review, and follow-up interviews with selected agencies reflecting a range of approaches to deal with moisture damage. This survey is being sent to the voting state DOT members of the AASHTO COMP for distribution to applicable employees. If you are not the appropriate person at your agency to complete this questionnaire, please forward this request to the correct person. Your cooperation in completing the questionnaire will help to ensure the success of this effort. The survey consists of 10 main questions with some follow up questions depending on your answers. We estimate that completion of this questionnaire should take less than 15-20 minutes. We respectfully request that this survey be completed and submitted by February 24, 2020. If you have any questions or problems with the survey, please contact Dr. Rebecca S. McDaniel. Thank you for your cooperation and assistance with this effort. Please provide your contact information: Name _____________________________________________________ Position/Title _______________________________________________ Agency ___________________________________________________ City ______________________________________________________ State _____________________________________________________ Phone ____________________________________________________ Email ____________________________________________________

Survey Questionnaire 57   May we please contact you for additional information? Yes No Please contact this person instead (name and contact info): ________________________________________________ 1. Is moisture damage considered a major issue affecting the durability of flexible pavements in your state? Yes No Would be a problem but the agency has tests and/or specifications to adequately address the problem. 2. Does your agency require testing asphalt mixtures or component materials for moisture susceptibility during mix design? Yes No Sometimes/under certain conditions. (Please specify.) ________________________________________________ Skip to 3 if 2. Does your agency require testing asphalt mixtures or component materials for moisture susceptibility = No

58 Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements 2a. What test method(s) is (are) required for mix design? (Check all that apply.) Modified Lottman Test (AASHTO T 283) Hamburg Wheel-Track Test (AASHTO T 324) Boiling Water Test (ASTM D3625) Static Immersion Test (AASHTO T 182) Immersion-Compression Test (AASHTO T 165) State devised or modified test method Other________________________________________________ 2b. What parameter(s) and criterion are used for mix design? (Example: minimum TSR 80%) ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ 2c. Has your state modified any parameters of a standardized test method for mix design? (Examples: test temperature, mixture conditioning) Yes (please explain, include a link, or send copy to Dr. Rebecca S. McDaniel) ________________________________________________ Unsure No 2d. Approximately what percentage of mixes fail testing criteria during mix design approval? ________________________________________________________________ Display this question if 2a. What test method(s) is (are) required for mix design? (Check all that apply.) = Hamburg Wheel-Track Test (AASHTO T 324)

Survey Questionnaire 59   2e. If Hamburg is used, how is stripping inflection point determined? ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ 3. Does your agency require testing asphalt mixtures or component materials for moisture susceptibility during production/acceptance? Yes No Sometimes/under certain conditions. (Please specify.) ________________________________________________ Skip to 4 if 3. Does your agency require testing asphalt mixtures or component materials for moisture susceptibility = No 3a. What test method(s) is (are) required for acceptance? (Check all that apply.) Modified Lottman Test (AASHTO T 283) Hamburg Wheel-Track Test (AASHTO T 324) Boiling Water Test (ASTM D3625) Static Immersion Test (AASHTO T 182) Immersion-Compression Test (AASHTO T 165) State devised or modified test method Other________________________________________________

60 Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements 3b. What parameter(s) and criterion are used for acceptance? (Example: minimum TSR 75%) ________________________________________________________________ 3c. Has your state modified any parameters of a standardized test method for acceptance? (Examples: test temperature, mixture conditioning) Yes (please explain, include a link or send copy to Dr. Rebecca S. McDaniel) ________________________________________________ Unsure No Display this question if 3a. What test method(s) is (are) required for acceptance? (Check all that apply.) = Hamburg Wheel-Track Test (AASHTO T 324) 3d. If Hamburg is used, how is stripping inflection point determined? ________________________________________________________________ 4. Does your agency require the use of any anti-strip additive(s) such as lime or liquid? Yes, for all mixtures Yes, for certain mixtures or materials (aggregates) Yes, based on results of testing No Skip to 5 if 4. Does your agency require the use of any anti-strip additive(s) such as lime or liquid? = No

Survey Questionnaire 61   4a. What types of anti-strip additives are allowed by your agency? (Check all that apply.) Hydrated lime added to moist aggregates Hydrated lime added to aggregate in pugmill Hydrated lime injected into the drum Hydrated lime slurry Liquid anti-strip additive added at terminal Liquid anti-strip additive added in plant asphalt storage tank Liquid anti-strip additive added through in-line blending at mix plant Other (please specify) ________________________________________________ 4b. What mixtures or materials require the use of an anti-strip additive? ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ 5. Does your agency use other measures – including alternate tests, limitations in your specifications, or other requirements – to mitigate moisture damage (examples: enhanced density requirements, field permeability testing, prohibiting use of certain aggregate types, Superpave5, or others)? ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________

62 Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements 6. What are the predominant aggregate types used in flexible pavements in your state? (Check all that apply.) Carbonates (e.g., limestone, dolomite) Sandstones (e.g., quartzite, greywacke) Granites or other igneous rocks (basalt, gabbro, diorite, etc.) Siliceous sands and gravels Chert Gneiss or other metamorphic rocks (slate, schist, marble, etc.) Blast furnace slag Steel slag Other, please specify ________________________________________________ 7. Is your agency implementing or researching the use of new or emerging technologies to identify moisture-susceptible materials or mixtures? Yes Considering No Skip to 8 if 7. Is your agency implementing or researching the use of new or emerging technologies to identify... = No

Survey Questionnaire 63   7a. Which technologies are you using or considering? (Check all that apply.) Surface free-energy analysis (universal sorption device, Wilhelmy plate, atomic force microscopy, calorimetry, etc.) MiST Rotary wheel tester Dynamic modulus differences between moisture conditioned and non-conditioned specimens Other, please specify ________________________________________________ 7b. Please identify the test method by including a link or emailing a copy to Dr. Rebecca S. McDaniel. ________________________________________________________________ 8. Has your state conducted or sponsored any research related to moisture susceptibility (currently or in the past)? Yes (please provide reference or link) ________________________________________________ No Not sure Considering the need

64 Practices for Assessing and Mitigating the Moisture Susceptibility of Asphalt Pavements 9. Do you see a need for additional research into any of the following? (Please click all that apply.) Improved lab tests to identify moisture-susceptible materials or mixtures Improved analysis of Hamburg stripping inflection point Improved anti-strip additive Correlation of lab testing and field performance related to moisture damage Construction or quality-assurance procedures to prevent moisture damage Other (please specify) ________________________________________________ 10. Would you be willing to participate in a follow-up interview with the principal investigator to provide additional details for a possible case example for the synthesis report? Yes No Display this question if 10. Would you be willing to participate in a follow-up interview with the principal investigator... = Yes 10a. If yes, please provide details or request consultant to call you to discuss at a time of your convenience. ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________