Limiting Damage to Flexible and Composite Pavements due to the Presence of Water Guidelines (2025) / Chapter Skim
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APPENDIX G: AGENCY AND INDUSTRY SURVEYS
APPENDIX G: AGENCY AND INDUSTRY SURVEYS
Pages 134-157
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From page 134... ...
. The industry survey was sent to the state asphalt and concrete associations, the American Concrete Pavement Association, the Asphalt Emulsion Manufactures Association, the Asphalt Interlayer Association, the Asphalt Recycling and Reclaiming Association, the FP2 for Pavement Preservation, the Geosynthetics Material Association, the International Slurry Surfacing Association, the National Asphalt Pavement Association, and the National Center for Pavement Preservation (total of seventy-three industry personnel)
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From page 135... ...
Asphalt pavement distress due to the presence of water. New Construction Rehabilitation Preservation 40 No.
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Of the responding agencies, 16 indicated premature failure or accelerated distress due to the presence of water in new asphalt pavements, while only one agency indicated an issue with new composite pavement construction (only 14 agencies indicated construction of new composite pavements)
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Agency Asphalt Pavements Composite Pavements New Rehab Pres New Rehab Pres Alabama DOT Alaska DOT&PF Alberta Transportation ― ― Arizona DOT California DOT Colorado DOT Connecticut DOT Florida DOT Hawaii DOT Idaho TD Indiana DOT Kansas DOT Kentucky TC Maine DOT Manitoba I&T Maryland SHA Michigan DOT ― ― ― ― Minnesota DOT Mississippi DOT Missouri DOT Nebraska DOR Nevada DOT New Brunswick DOTI New Jersey DOT New York State DOT ― Ohio DOT Oklahoma DOT Ontario MOT Oregon DOT Pennsylvania DOT Saskatchewan MHI South Carolina DOT South Dakota DOT Tennessee DOT Texas DOT Virginia DOT Washington State DOT West Virginia DOH ― Wisconsin DOT = Water-related damage not an issue -- no premature failures or accelerated distress. = Water-related damage an issue -- premature failures or accelerated distress.
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From page 138... ...
will be considered for use as case studies or agency examples in the guidelines. Agency practices that have helped to minimize premature failure or accelerated distress are summarized in Tables G-2 and G-3 for asphalt and composite pavements, respectively.
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From page 139... ...
• Use geosynthetic. • Tighter requirements on • Remove weak soils, place bituminous material.
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Drainage Feature Interstate Principal Minor Arterial Collector Arterial Urban Rural Urban Rural Urban Rural Urban Rural Ditches 21 30 21 30 20 28 18 24 Curb and gutter 21 6 31 12 29 13 24 9 Underdrain 18 16 17 16 11 10 8 8 Daylighted base 10 18 9 17 10 17 9 13 Edge drains 17 16 14 14 9 9 8 8 Aggregate permeable base 10 11 10 11 10 11 9 9 Geosynthetic separator layer 12 13 10 11 9 10 6 6 French drains 9 11 9 11 7 8 7 6 Asphalt-treated permeable base 11 11 8 8 4 4 4 4 Retrofit edge drains 9 8 5 8 2 3 1 2 Open-graded friction course 8 8 7 6 2 2 2 2 Cement-treated permeable base 6 5 4 3 2 2 1 1 Permeable friction course 6 6 4 4 2 2 0 0 Fin drains 2 2 2 3 0 1 0 0 Note: values shown represent number of responding agencies. Agencies were asked to indicate if a drainage design checklist was used to assist the designer in determining if and when special designs are warranted for mitigating existing water or potential water problems.
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Practices for Addressing Weak Soils Figure G-7 provides a summary of agency practices for addressing weak soil conditions. The primary practices include removing and replacing weak soil with higher quality material (twentyeight responses)
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. Materials Agencies responded to a number of questions related to material properties for aggregate base, asphalt- and cement-treated permeable base, geosynthetics, and asphalt materials.
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Agency permeable base material specifications. Material Property Aggregate Base or Asphalt-Treated Cement-Treated Separator Layer L.A.
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• Predominate asphalt mixture type used by responding agencies include (see Figure G-10) : − Dense-graded (thirty-two responses)
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Agency approved asphalt mixture additives. Note: Responses have been supplemented with the results from a survey conducted in December 2014 by the AASHTO Subcommittee on Materials.
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1 After pavement (placed at edge of outside shoulder) 1 Verifying Drain Functionality Agency specification for inspection and repair 16 Contractor option 5 Permeable Aggregate Base/Separator Layer Aggregate gradation 18 Layer thickness 17 In-place density 14 Number of passes 4 Asphalt-Treated Permeable Base Layer thickness 12 Binder content 9 Aggregate gradation 8 In-place density 7 Placement temperature 6 Number of passes 6 Compaction temperature 4 Permeability/drainability 1 Asphalt Mixture Placement Density Cores 28 Nuclear density gauge 24 Non-nuclear density gauge 6 Cement-Treated Permeable Base Layer thickness 9 Aggregate gradation 6 Curing method 6 Cement content 5 In-place density 4 146
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. Chip seal, thin asphalt overlay, and microsurfacing applications on composite pavements are conducted by half of the responding agencies, and ten agencies indicated the use of surface seals.
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Agency composite pavement preservation activities. Rehabilitation A summary of agency responses for asphalt pavement rehabilitation treatments for mitigating damage due to the presence of water is shown in Figure G-16.
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From page 149... ...
indicated milling followed by an asphalt overlay as an effective treatment for mitigating damage to composite pavements due to the presence of water (Figure G-17)
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From page 150... ...
Agency assessment of drainage and pavement feature effectiveness. Feature/Condition Effectiveness 1 2 3 4 5 Asphalt mixture additives 1 2 7 9 12 Asphalt mixture aggregate quality 1 3 6 12 8 Asphalt mixture air voids/in-place density 1 2 4 10 10 Pavement drainage design 0 3 5 5 14 Asphalt mixture binder content 1 2 10 12 4 Asphalt mixture type 1 3 8 6 8 Environmental conditions 1 2 12 6 4 Traffic level considerations 3 1 11 8 0 Base type 1 4 12 2 5 Pavement age consideration 2 2 14 3 0 Notes: – Values shown represent number of responding agencies.
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From page 151... ...
While the results of the industry survey indicated that edge drains and underdrains were more effective than fin drains and aggregate trenches in removing water from the pavement structure, very few of the industry responses indicated that these drainage systems were effective in removing water from the pavement structure.
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From page 152... ...
were also effective methods for addressing weak soils. Only three industry members indicated increasing the asphalt layer thickness and only two industry members indicated increased the concrete layer thickness (for composite pavements)
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As shown in Figure G-21, the industry rank order of effective methods for addressing high or perched water tables is the same as the agency responses. Industry Agency 12 No.
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The agency ranking of the effective methods for measuring subgrade compaction is similar to those of the industry responses. Industry Agency 12 No.
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Industry assessment of effective methods for controlling placement of aggregate base/separator layers. • The industry responses for effective methods for controlling placement of asphalt-treated permeable base, as well as comparison to agency responses, are provided in Figure G-25.
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Industry assessment of effective methods for controlling placement of asphalt-treated permeable base. • The industry responses for the methods for controlling placement of cement-treated permeable base are shown in Figure G-26.
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From page 157... ...
Industry assessment of effective methods for controlling placement of asphalt mixtures.
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