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Recycling and Reclamation of Asphalt Pavements Using In-Place Methods (2011)

Chapter: CHAPTER FOUR Specifications

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Page 35
Suggested Citation:"CHAPTER FOUR Specifications." National Academies of Sciences, Engineering, and Medicine. 2011. Recycling and Reclamation of Asphalt Pavements Using In-Place Methods. Washington, DC: The National Academies Press. doi: 10.17226/14568.
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Page 35
Page 36
Suggested Citation:"CHAPTER FOUR Specifications." National Academies of Sciences, Engineering, and Medicine. 2011. Recycling and Reclamation of Asphalt Pavements Using In-Place Methods. Washington, DC: The National Academies Press. doi: 10.17226/14568.
×
Page 36
Page 37
Suggested Citation:"CHAPTER FOUR Specifications." National Academies of Sciences, Engineering, and Medicine. 2011. Recycling and Reclamation of Asphalt Pavements Using In-Place Methods. Washington, DC: The National Academies Press. doi: 10.17226/14568.
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Page 37

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33 CHAPTER FOUR SPECIFICATIONS (Table 33). The use of a method specification tends to con- tradict state preferences for allowing the contractor to design the recycled mix and field adjust the designs as needed. TABLE 32 WRITTEN RESPONSES FOR USE OF WARRANTIES Warranty: Does your agency specify a warranty period for the different in-situ recycling processes. If so, what is the length of the warranty and what type of assurance is required? Written Responses from Agencies Written Responses from Contractors Warranty—3 yr for rutting, cracking, delaminations, raveling, and smooth- ness (FL) Warranty—5 yr period; bond required (WI) Warranty—none (AL, AK, AZ, AR, CA, CO, CT, DC, DE, GA, IA, ID, KS, KY, MO, MT, NC, ND, NE, NV, NY, PA, SC, SD, TX, UT, VA, WA, WY) Warranty—under consideration (VT) Warranty—under development (IL) 1-yr warranty (4) 2-yr warranty bond for 100% (2) 3-yr warranty bond for 100% 3-yr warranty materials; bonding company has issues with 3 years 4-yr warranty bond for 50% of construction cost; Performance measures: fatigue, edge crack- ing, rutting, potholes; nothing HMA related No experience (3) TABLE 33 STATE RESPONSES FOR TYPE OF SPECIFICATION USED FOR RECYCLING PROJECTS Question: Specifications: What type of specifications does your agency use? Surface Treatments Agency Responses HIR CIR FDR Method AR, AZ, CA, FL, IA, ID, KY, MD, MO, MT, NC, NE, WI AZ, CA, CO, DE, FL, IA, ID, MN, MO, MT, NC, ND, NE, NH, NV, OR, RI, SD, UT, VA, VT, WI, WY CA, CO, DE, GA, IA, ID, MD, MN, MO, MT, NC, ND, NE, NH, NV, OR, SD, TX, UT, VA, VT, WY End Results CO, KS, KY, MO, TX CO, IA, KS, MO, NV, ONT AK, CO, GA, IA, MO, NV, SC Performance CA, CO, DC, TN, TX CA, DC, TN CA, DC, TN Warranty FL FL, WI NY Note: Some states indicated they may use more than one type of specification. The content and extent of what is defined in a specifica- tion depend on the type of specification used by an agency. Regardless of the type of specification, they generally con- tain the following sections: 1. Description: Define the type of process to be used. 2. Materials: List all materials, specifications, test methods, and mix composition to be used (method specification). For end result, performance, and war- ranty specifications, identify who is responsible for these decisions. 3. Construction Requirements: Identify key require- ments for weather, surface preparation, equipment, material properties (e.g., moisture content of RAP, mix temperatures) for method specifications. For end result, performance, and warranty specifica- tions, identify who is responsible for these decisions. Information on minimum expectations for materi- als, workmanship, and performance criteria is also included in this section. 4. Method of Measurement: Define the units for each product or material to be measured (e.g., liquid RA in gallons, cement slurry in tons, square yard of surface) and how performance criteria are measured. 5. Basis of Payment: Define payment for accepted quan- tities and include description of what is included in the units. State agency respondents were asked to identify the type of specifications used for in-place recycling projects. Method specifications are most frequently used (Table 32), which indicates that the states define what materials will be used and how they will be placed. End result specifications are used by some states, and neither performance nor warranty specifications are commonly used by states. The responses to the use of warranties for recycling projects show that only two states use warranties of 3- and 5-year durations

34 Contractors are likely to have some experience with a range of specification types (Figure 29). The length of the warranty period ranges from 1 to 4 years. Shorter warranties (3 years or less) require the full cost of the recycling to be bonded but are reduced to 50% for longer warranty periods. Distresses specifically related to the surface treatment (e.g., HMA overlay) are excluded from the warranty. Performance measurements include fatigue cracking, edge cracking, rut- ting, and pothole formation. A closer examination of these nonstate agency warranty programs could provide key infor- mation regarding performance history, performance criteria limits, warranty successes, and warranty administration. FIGURE 29 Experience of agencies and contractors with different types of in-place recycling specifications. Percentages are based on the number of agencies and contractors with experience using the specific recycling process. The agency and contractor responses were used to rank and summarize the current use of different types of specifi- cations for in-place recycling projects (Table 34). TABLE 34 TYPES OF SPECIFICATIONS USED FOR IN-PLACE RECYCLING Type of Specification HIR CIR FDR Method Often Often** Frequently End Result Sometimes* Sometimes Frequently Performance Sometimes* Sometimes* Often* Warranty Sometimes* Sometimes Often* Rarely = lower than 10% average of agency and contractor with experience. Sometimes = between 10% and 25% average of agency and contractor with experience. Often = between 25% and 50% average of agency and contractor with experience. Frequently = greater than 50% average of agency and contractor with experience. *Contractor response was significantly higher than agency with experience. **Agency response was significantly higher than contractor with experience. Method specifications are commonly used by agencies for in-place recycling projects. However, agencies also rou- tinely require the contractor to select additives and provide mix designs and make field adjustments for in-place recy- cling projects, which suggests that end result or short-term performance specifications are more appropriate types of contracting approaches. Materials testing, mixture testing, and specification par- ticulars were not well defined from the survey responses. Therefore, a combination of agency survey information, a search for existing state specification in the National High- way Specification website (FHWA 2010), and a literature search was used to help define typical characteristics of in- place recycling specifications. Key word searches of the National Highway Specifica- tion website were conducted for this information (Table 35). The key word search was conducted for “all agencies” and “all categories,” which include standard specifications and supplements as well as innovations and emerging specifi- cations. The majority of the titles for each hit were evalu- ated for descriptions of in-place recycling methods of HMA. Unfortunately, a number of the search hits were related to a range of other topics (e.g., fly ash, slag, glass, and shin- gles). Cold planning was usually associated with milling for removal and use in central plant applications. TABLE 35 SPECIFICATION SEARCH PARAMETERS Key Word(s) No. of Hits Reclamation 56 Pulverized 134 Cold planning 445 Reconditioning 51 Reclaimed 228 Reclaimed base 165 Full depth recycling 228 Recycling, recycled 343 CIR 133 HIR 3 Hot-in-place Crashed Cold-in-place 8 The specifications referring to in-place recycling of HMA had little consistency in titles or terms (Table 36). The lack of consistent terminology made key word searching difficult and a simple summary impossible. Examples of the range of spec- ifications found in the search are provided in Appendix B. Wisconsin Specification Section 325 is an example of the simplest version of an FDR specification. The only specifics provided in this specification are requirements for a maxi- mum of 97% of the 50-mm (2-in.) RAP, timing of general recycling activities, types of compactors for different lift thicknesses, and a description of what is included in the pay- ment measurement (square yard).

35 moisture content or dust control, paver (pick up, screed), construction timing and sequencing, weather conditions for paving (no foggy, rainy conditions), curing (calcium chloride curing compound, until 1% moisture), testing (gradation, den- sity, optimum moisture), payment measurement (square yard, square meter, tons of new materials, gallons of liquid stabiliz- ers), and what is included in the area measurement payment. There is no consistent use of in-place recycling terms or specification content. It would be useful if there were uniform guidelines for specification development and stan- dardization of terms. TABLE 36 IN-PLACE RECYCLING SPECIFICATIONS FOUND IN NATIONAL HIGHWAY SPECIFICATION WEBSITE State Section Title California Special Provisions CIR and full depth reclamation Connecticut 4.03 Cold reclaimed asphalt pavement Illinois Article 663 Asphalt pavements—hot-in-place recycling Iowa 2318 Cold-in-place asphalt pavement recycling 2125 Reclaiming present surfacing material (in-place or central plant) 2318 Cold-in-place asphalt pavement recycling Georgia 403 Hot-in-place recycled asphaltic concrete Kansas 605 Surface recycled asphalt construction Maine 307 Full depth reclamation Massachusetts 403 Reclaimed base course Mississippi 305 In grade modification Missouri JSP-04-12A One inch continuous process hot-in-place recycling with alternate methods of surfacing JSP-04-12B Two inch continuous process hot-in-place recycling with alternate methods of surfacing Montana 302 Bituminous pavement pulverization New Hampshire 306 Reclaimed stabilized base New York 402.6 Hot-in-place recycling of hot mix asphalt Oklahoma 311 Processing existing base and surface Pennsylvania 341 Cold recycled bituminous base course, cold-in-place Texas Item 358 Asphalt concrete surface rehabilitation Utah 02962 In-place cold recycled asphaltic base Vermont 310 Reclaimed stabilized base 409 Cold mixed recycled bituminous pavement Wisconsin 325 Pulverized and re-laid pavement Ontario, Canada OPSS 333 Construction specification for cold-in-place recycling OPSS 331 Construction specification for full depth reclamation OPSS 335 Construction specification for cold-in-place recycling with expanded asphalt Kansas and Georgia specifications had errors on state specification sites. A more complex specification is Maine Specification 307 for FDR. This specification includes information on the size of the pulverized materials, new aggregate (as needed to meet gradation), equipment (pulverizer, grader, rollers, pulverizing), weather limitations, and testing for density control (nuclear gauge). Other specifications may or may not include specific direc- tions for surface preparation (sweeper or cutter to protect adja- cent surfaces), pulverizer features (self-propelled, automatic depth control), mixer (self-propelled, automatic depth control, liquid distributor, rotary pugmill), water truck for optimum

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TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 421: Recycling and Reclamation of Asphalt Pavements Using In-Place Methods discusses the use of hot in-place recycling, cold in-place recycling, and full-depth reclamation of asphalt pavements.

In-place recycling and reclamation of asphalt pavements provides agencies with the ability to optimize the value of in-place materials, minimize construction time and traffic flow disruptions, and reduce the number of construction vehicles moving in and out of the construction area.

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