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74 APPENDIX A Chip Seal Synthesis Questionnaire The following pages contain the questionnaire that was dis- as a number of chip seal contractors that expressed an inter- tributed to state department of transportation (DOT) mainte- est in the project. Table A1 is a list of the respondents from nance directors, similar positions in 10 foreign countries, which the results of this report are drawn. points of contact at the county and municipal level, as well TABLE A1 SUMMARY OF CHIP SEAL SYNTHESIS SURVEY RESPONSES Canadian U.S. Canadian International Other U.S. DOTs Local Local Agencies Province DOTs Agencies Responses Agencies Alaska (2) Lubbock, TX Alberta Ottawa, ON New Zealand Faehrner Arizona Austin, TX British Columbia Halifax, NS Transit (3) Asphalt Arkansas Missoula, MT Manitoba (WI California Des Moines, IA contractor) Colorado (6) Connecticut Salt Lake City, Saskatchewan Australia: Koch Florida (NP) UT New Brunswick Victoria Materials Georgia Tulsa, OK Ontario Northern (Midwest Hawaii (NP) Quebec Territory MN) Idaho (3) Contra Costa Newfoundland Australia: Indiana County, CA Nova Scotia Tasmania Illinois (NP) Washington Mainroads Iowa County, OR (Western Kansas Australia) Kentucky San Diego Price Edward South Africa Louisiana County, CA Island United Maine (NP) Yukon Kingdom Maryland Territories (2) Michigan Minnesota (2) Mississippi Missouri Montana Nebraska Nevada New Hampshire (NP) New Jersey (NP) New Mexico New York North Carolina North Dakota Oklahoma Ohio Pennsylvania Rhode Island South Carolina Texas (3) Vermont (NP) Virginia Washington Wyoming NP = No chip seal program.
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75 NCHRP SYNTHESIS 35-02 CHIP SEAL BEST PRACTICES PURPOSE OF THE SYNTHESIS larly successful chip seal best practice are invited to indicate their willingness to contribute detailed information about the Chip seal is one of the most frequently used preventive main- project, and they will be contacted individually by the tenance treatments on flexible pavements. For purposes of researcher to obtain the case study information. this study and questionnaire, the term "chip seal" is defined as a single or double course of aggregate placed on an asphalt The results of this synthesis will be shared and distributed binder that has been applied to the surface of an existing through AASHTO, FHWA, TRB, and others, with the goal pavement. Much of the practice is based on local anecdotal of assisting in the development and implementation of pave- experience rather than sound engineering principles, and ment preservation programs. I want to thank you in advance while the design and installation of chip seals involve a sig- for your support for this project. We do not often get the nificant degree of "art," a strong body of knowledge on the opportunity to do substantive research in the field of highway subject has been developed and is scattered throughout the maintenance and as this field is so vital to the health of a literature of transportation organizations, government agen- nation's transportation system, this project's results will fur- cies, and academia. Technical information is available on nish a means to disseminate the experience of maintenance good practice for materials, design, construction techniques, engineers from around the world in a very straightforward and effectiveness of chip seals, and will be summarized in a fashion. synthesis. The project's scope will be limited to single- and double-course preventive maintenance chip seal surface When you have completed this survey, please return it by treatments. January 12, 2004 by any convenient means to This questionnaire will take approximately 45 minutes to Douglas D. Gransberg, PE complete. The purpose of this questionnaire is to collect spe- University of Oklahoma cific information on chip seal practices from sources ranging 830 Van Vleet Oval, Room 162 from the municipal to the international level. Additionally, Norman, OK 73019-6141 those respondents that believe that they have a chip seal proj- Fax: 405-325-7558 ect that would make a good case study to illustrate a particu- E-mail: firstname.lastname@example.org
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76 RESPONDENT INFORMATION Agency/organization name: State: Country: USA Other country, please specify: Mailing address: Point of contact name: ; Point of contact phone: ; Point of contact fax: ; Point of contact e-mail address: ; Type of agency/organization: Federal agency State/provincial agency County agency Municipal agency Other public agency, please specify: Private organization If private, what type? Engineering/design/planning firm Construction company Material supplier Professional or trade organization Other private organization, please specify: Chip seal involvement: Primary business activity or program Major portion of routine business activity or program Minor portion of routine business activity or program Occasional chip seal projects Do you have a potential case study project that you would be willing to share specific detailed information about to illustrate an important "Best Practice" or "Lesson Learned" by your organization? Yes No If the answer to the above question is Yes? What is the name of the project? What is the "Best Practice" or "Lesson Learned"? Please answer the following questions to the best of your knowledge. If providing an exact answer will require more time than you can allow, please furnish your best estimate. If you are a non-U.S. respondent, when asked to furnish cost data, please indicate the national currency that you are using in your response. If you have questions on the proper interpretation of the questionnaire, please e-mail the researcher at email@example.com. We greatly appreciate your time and support for this syn- thesis project. Questions for Respondents A. General 1. At this time, what proportion of your highway lane miles have chip seals or surface treatments as the wearing course? Total centerline miles/ km miles/ km with chip seal Rural--local Rural--collector Rural--arterial Rural--interstate Urban--local Urban--collector Urban--arterial Urban--interstate
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77 2. Do you follow a specific preventive maintenance cycle for chip seals? Yes No 3. If the answer to Question 2 is Yes, what is the cycle length? Roughly every years. 4. What is the typical life span (age or traffic applications) of a chip seal in your agency? Approximately years or approximately ESALs on major roads Approximately years or approximately ESALs on minor roads 5. What percentage of your chip seal work is done with in-house crews? Approximately % 6. How much chip seal work does your agency do each year? Approximately US$/year or other national currency /year which includes approximately lane miles/year or lane kilometers/year 7. How do you rate your organization's experience with the performance of in-house chip seals? (Check one box only.) Excellent; we have very little difficulty with in-house chip seal performance. Good; we have minor difficulties with in-house chip seal performance. Fair; we have routine, manageable difficulties with in-house chip seal performance. Poor; we have serious difficulties with in-house chip seal performance. Unacceptable; we use in-house chip seals when it is the only alternative. Not applicable; we do not use in-house chip seals. 8. How do you rate your organization's experience with the performance of contract chip seals? (Check one box only.) Excellent; we have very little difficulty with contract chip seal performance. Good; we have minor difficulties with contract chip seal performance. Fair; we have routine, manageable difficulties with contract chip seal performance. Poor; we have serious difficulties with contract chip seal performance. Unacceptable; we use contract chip seals when it is the only alternative. Not applicable; we do not use contract chip seals. 9. What are the primary problems associated with in-house chip seal work? (Check all that apply and indicate the single problem that is most common.) Check only one Early loss of aggregate most common Loss of aggregate due to cool evenings most common Premature flushing/bleeding most common Loss of aggregate over patches most common Flushing/bleeding over patches most common Flushing/bleeding at intersections and turning areas most common Other, please specify: most common 10. What are the primary problems associated with contract chip seal work? (Check all that apply and indicate the single prob- lem that is most common.) Check only one Early loss of aggregate most common Loss of aggregate due to cool evenings most common Premature flushing/bleeding most common Flushing/bleeding over patches most common Flushing/bleeding at intersections and turning areas most common Other, please specify: most common 11. Which approach seems to yield a better final chip seal product? Agency constructed Contractor constructed No difference
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78 B. Design 12. Does your organization design chip seal projects? Yes No If No, please skip down to Section C, Contracting Procedures. 13. How do you characterize existing pavement conditions during the design of chip seal applications? Penetrometer Level of oxidation (hunger factor) Qualitative factors Other method, please specify: Don't characterize existing conditions 14. What is the major reason for your organization's decision to apply a chip seal to a given pavement? (Check one box only.) Distress (cracking) Improve skid resistance Prevent water infiltration Provide a wearing surface Oxidation Raveling Eliminate surface rutting Improve night vision Improve contrast between stripes and road surface Other, please specify: 15. What is the "trigger point" in your chip seal decision-making process? Pavement condition rating or index Level/amount of cracking Skid number Amount of oxidation Age of the surface No trigger point Other reason, please specify: 16. What is the design procedure you use? Kearby Method McLeod Method Modified Kearby Method Penetrometer per U.K. Road Note 39 Asphalt Institute Method (MS-19) Modified Marshall Hammer per New Zealand TNZ P17 Method Sand patch testing Empirical method based on past experience No formal design method Individual organizational method Please briefly describe your process or attach a copy of your design method to this questionnaire when you submit it. No design. Chip seal is treated as a commodity and the chip seal contractor or the agency in-house staff determines the appropriate design 17. What design criteria are used? (Check all that apply.) Pavement condition Absorption factor/oxidation Traffic volume Turning movements Percent trucks Texture factor Weather (cold/hot/rain/humidity) Precoat condition (green/dry) Source of asphalt Residual factor Number and width of lanes Other, please specify: 18. Who performs the design? Agency in-house design section. Agency in-house construction group. Agency in-house maintenance group. Design consultant under design contract. Chip seal contractor under the construction contract. Other, please specify:
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79 19. For how long has the current design procedure been used? years. 20. How do you determine the binder rates? Compute using design procedure Based on past experience Chip seal contractor sets the rates Agency in-house staff set the rates Other, please specify: 21. How do you determine the aggregate rates? Compute using design procedure Based on past experience Chip seal contractor sets the rates Agency in-house staff set the rates Other, please specify: 22. How would you describe the level of distress (cracks) on roads that generally receive a chip seal? Severe Moderate Slight None 23. How do you characterize the pavement's structural cross section on roads that generally receive a chip seal? Excellent Good Fair Poor Very Poor C. Contracting Procedures 24. Do you feel that an adequate number of experienced chip seal contractors bid on your jobs? Yes No 25. How many chip seal contractors typically bid on your jobs? 13 46 79 Over 10 26. Do you have a prequalified list of contractors that are allowed to bid on your chip seal projects? Yes No 27. Do you require warranties in your chip seal projects? Yes No If so, what is the length of the warranty? weeks/months/years 28. What is your typical chip seal construction season? From the month of to the month of 29. Do you require different binderaggregate combinations for chip seals in different types of highways? Yes No 30. If the answer to Question 29 is Yes, what is the factor that differentiates between the different requirements? Number of lanes Average daily traffic Proximity to urban areas Proximity to specialized aggregate sources like lightweight aggregates Other, please specify: 31. What types of contracts do you use for chip seal projects? (Check all that apply.) Unit pricelow bid Lump sum/firm fixed price Cost plus Indefinite delivery/indefinite quantity Designbuild 32. What is the range for the length of a typical chip seal project? lane miles or lane kilometers 33. What is the maximum traffic volume on roads on which your agency constructs chip seals? ADT < 500 ADT < 1,000 ADT < 2,000 ADT 20,000
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80 D. Materials 34. What uniformly graded aggregates gradation(s) do you use for your chip seal jobs? (Check all that apply.) 5/8 in. or 16.0 mm 1/2 in. or 12.5 mm 3/8 in. or 10 mm Other, please specify: Which gradation is most commonly used? 35. What well-graded aggregates gradation(s) do you use for your chip seal jobs? (Check all that apply.) 5/8 in. minus or 16.0 mm minus 1/2 in. minus or 12.5 mm minus 3/8 in. minus or 10 mm minus Other, please specify: Which gradation is most commonly used? 36. Are any special gradations used? Yes No If Yes, please specify the special gradations: 37. Do you use more than one gradation of aggregate if doing a two course surface treatment? Yes No If Yes, please specify the special gradations: 38. Do you use precoated aggregates on Asphalt cement chip seals? Yes No If Yes, what do you use for precoating material? Emulsion chip seals? Yes No If Yes, what do you use for precoating material? 39. Have you ever used synthetic aggregates for your chip seals? Yes No If Yes, do you use Lightweight aggregate? Crushed slag aggregate? Other, please specify: If you regularly use synthetic aggregates, please indicate those situations where you typically specify these aggregates: 40. What is the typical cost for your aggregates? Natural stone or gravel chip seal aggregate: $/ton or currency/ton Lightweight chip seal aggregate: $/ton or currency/ton Crushed slag chip seal aggregate: $/ton or currency/ton Other, please specify: $/ton or currency/ton 41. What types of natural aggregate are typically used on your chip seal projects? Limestone % of program Quartzite % of program Granite % of program Trap rock (igneous) % of program Sandstone % of program Natural gravels % of program Other, please specify: % of program 42. What binder types do you normally use in the organization? Please indicate the percent usage on an annual basis and aver- age unit price for each type. AC 2.5 % of program $/gal or currency/liter AC 5 % of program $/gal or currency/liter AC 5-latex % of program $/gal or currency/liter
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81 AC 10 % of program $/gal or currency/liter AC 10-latex % of program $/gal or currency/liter AC 15P % of program $/gal or currency/liter AC15-5TR % of program $/gal or currency/liter AC20 % of program $/gal or currency/liter AC 40 % of program $/gal or currency/liter CRS-1 % of program $/gal or currency/liter CRS-1H % of program $/gal or currency/liter CRS-1P % of program $/gal or currency/liter CRS-2 % of program $/gal or currency/liter CRS-2H % of program $/gal or currency/liter CRS-2P % of program $/gal or currency/liter HFRS % of program $/gal or currency/liter HFRS-2P % of program $/gal or currency/liter Other % of program $/gal or currency/liter 43. How do you select the binder type for chip seal jobs? Local climate Traffic level of road to be sealed Season in which seal will be applied Past experience Design procedure determines it Other, please specify: 44. Do you use modifiers with your asphalt or emulsions? Yes No If Yes, what modifiers are allowed for use? (Check all that apply.) Polymers Latex Rubber crumb Anti-stripping agents Additives Other, please specify: 45. Has your agency constructed any geotextile-reinforced chip seals? Yes No If Yes, have the geotextile-reinforced chip seals been successful? Yes No E. Equipment 46. Do you require computerized controls on your distributors? Yes No 47. Do you require computerized gate controls on your chip spreaders? Yes No 48. What roller types are considered appropriate for use on chip seals using emulsion binders? Static steel Vibratory steel Pneumatic-tired Combination pneumatic/steel Combination vibratory/pneumatic Other, please specify: 49. What roller types are considered appropriate for use on chip seals using asphalt binders? Static steel Vibratory steel Pneumatic-tired Combination pneumatic/steel Combination vibratory/pneumatic Other, please specify: 50. Do you require any specific makes and models (proprietary specifications) for the chip seal equipment? Yes No If Yes, for which of the following equipment? (Check all that apply.) Binder distributors Aggregate spreaders
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82 Rollers/rolling equipment Sweeping equipment Traffic control equipment/devices Other, please specify: F. Construction 51. Prior to chip sealing, what road preparation methods are typically performed for the existing surface? Chip seal placed on freshly paved asphalt surface Crack sealing Fog coat Cold mix patch and level Geotextile to retard reflective cracking Other, please specify: 52. What are your specifications for ambient air temperature to do chip seal work? degrees No specification 53. What are your specifications for pavement temperature to do chip seal work? degrees No specification 54. How soon after the binder spray operation is aggregate spread? minutes Is this different for asphalt concrete and emulsion? Yes No 55. What is the typical time span between aggregate spread and initial rolling? 56. What is the typical number of pneumatic-tired rollers required? One Two Three Four Other, please specify: 57. What is the typical number of steel-wheeled rollers required? One Two Three Four Other, please specify: 58. Which of the following controls are in place for your roller operations? Number of passes Rolling patterns Speed limits Roller weight Other, please specify: 59. What is the typical time span between final rolling and initial brooming? 60. What is the typical number of broom passes? One Two Three Other, please specify: 61. What traffic control measures are typically required? Reduced speed Interim pavement markings and devices Pilot vehicles Flaggers Other, please specify: 62. What is the typical maximum reduced speed allowed? mph/km/h 63. What is the typical time span between final rolling and opening to reduced speed traffic? minutes/hours 64. What is the typical time span between final rolling and opening to full speed traffic? minutes/hours 65. Do you require a scrub seal or fog seal to be applied on a fresh chip seal? Yes No If Yes, please indicate how long after the seal. Next day hours Other, please specify:
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83 G. Quality Control 66. Who performs the final inspection? Your agency Private consultant Contractor How many people perform the inspection? Individual Team 67. Which of the following tests are performed on your aggregate? Percent fracture Flakiness index Decant test Anti-strip test (compatibility with binder) Tests for the presence of clay Percent sodium sulfate loss (resistance to freezethaw) Other, please specify: 68. Do you perform any field tests to monitor the quality of the binder? Yes No If Yes, what are they? 69. Do you require calibration of binder spray equipment? Yes No If Yes, how often? 70. Do you require calibration of aggregate spreading equipment? Yes No If Yes, how often? 71. What tolerances are allowed for binder spray and aggregate spread rates? Binder spray ± gal/sy or L/sm Aggregate spread ± lb/sy or kg/sm 72. Beyond calibration of chip spreader and binder distributors, do you perform any other field tests to check material appli- cation rates? Yes No 73. If Yes, what is it called? Please attach a copy of the test to this questionnaire if possible. 74. Are any special quality control tests employed by your agency? Yes No If Yes, please specify: H. Performance 75. What common distresses are observed in your chip seals? To the right, please indicate the top three distresses in order of occurrence. Potholes Raveling Bleeding 1. __________ Corrugation Crack reflection 2. __________ Streaking Transverse joints 3. __________ Longitudinal joints Other, please specify: 76. Which factor is most important in minimizing defects? (Check one box only.) Construction procedure Design method Better binder Better aggregates Quality control Double seal Other, please specify: 77. What is the most common public-user complaint about a chip seal? (Check one box only.) Loose stone Road noise Vehicle ride Appearance Other, please specify:
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84 78. How would you describe the pavement ride on roads that generally receive a chip seal? Excellent Good Fair Poor Very Poor 79. Of your organization's chip seal failures, which of the following was a likely cause? To the right, please indicate the top three distresses in order of importance. Weather 1. __________ Insufficient rolling Improper binder application rate 2. __________ Improper aggregate rate Aggregate spread early 3. __________ Aggregate spread late Dirty or dusty aggregate Aggregate gradation Improper binder viscosity Improper binder temperature Other, please specify: 80. Which factors are most critical in determining the life of your chip seals? Original quality Traffic Underlying structure Maintenance spending Friction loss Cold climate considerations (freezethaw cycles, snowplowing, etc.) 81. Which methods do you use to maintain your chip seals? (Check all that apply.) Crack sealing Seal patch Sanding or chat Lime slurry Fog seal Local strengthening Other, please specify: If there is anything that you would like to add that was not covered in this questionnaire that you feel would benefit this study, please write your comments below: THANK YOU FOR SUPPORTING THIS IMPORTANT EFFORT Please respond by January 12, 2004