Thin and Ultra-Thin Whitetopping (2004)

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51 APPENDIX A Responding Agency Information Responding Agency City State Alaska DOT & Public Facilities (PF) Juneau AK Arizona DOT Phoenix AZ Arkansas State Highway and Trans. Dept. (SH&TD) Little Rock AR Colorado DOT Aurora CO Connecticut DOT Rocky Hill CT Delaware DOT Dover DE Florida DOT Tallahassee FL Georgia DOT Forest Park GA Hawaii DOT Honolulu HI Illinois DOT Springfield IL Indiana DOT West Lafayette IN Iowa DOT Ames IA Kansas DOT Topeka KS Louisiana DOTD Louisiana Trans. Res. Center (LTRC) Baton Rouge LA Maine DOT Augusta ME Maryland State Highway Administration (SHA) Brooklandville MD Michigan DOT Lansing MI Minnesota DOT Maplewood MN Mississippi DOT Jackson MS Montana DOT Helena MT Nebraska Department of Roads (DOR) Omaha NE New Hampshire DOT Concord NH New Jersey DOT Trenton NJ New York State DOT Albany NY North Dakota DOT Bismarck ND Ohio DOT Columbus OH Oklahoma DOT Antlers OK Oregon DOT Eugene OR South Carolina DOT Columbia SC South Dakota DOT Pierre SD Texas DOT Austin TX Utah DOT Salt Lake City UT Vermont Agency of Transportation Montpelier VT Virginia DOT Virginia Trans. Research Council (VTRC) Charlottesville VA Washington State DOT Olympia WA Wisconsin DOT Madison WI Wyoming DOT Cheyenne WY ACPA—Illinois Chapter, Inc. Springfield IL ACPA—Missouri/Kansas Chapter Overland Park KS ACPA—NE Chapter Caldwell NJ ACPA—NE Chapter Buffalo NY ACPA—Oklahoma/Arkansas Chapter Oklahoma City OK ACPA—Utah Chapter Park City UT F.A. Rohr Bach, Inc. (Contractor) Allentown PA Ministry of Transportation, British Columbia Victoria (Canada) BC Manitoba Transportation and Government Services Winnipeg (Canada) MB New Brunswick DOT Fredericton (Canada) NB Dept. Works, Srvcs. & Trans., Newfoundland and Labrador St. John’s (Canada) NL Ministere des Transports du Quebec Quebec (Canada) QC

52 GENERAL 1. How many whitetopping overlay projects has your organization been involved in the last year? Average 0.9 projects per respondent. Average 2.3 projects per respondent with at least one project. Maximum 10 projects. 2. Of those, approximately what percentage are UTW [less than or equal to 100 mm (4 in.)]? Average 66%. 3. How many in the last five years? Average 4.2 projects per respondent. Average 6.0 projects per respondent with at least one project. Maximum 40 projects. 4. How many in total? Average 5.6 projects per respondent. Average 6.6 projects per respondent with at least one project. Maximum 50 projects. Over what period of time (years)? Average 8 years. Minimum 1 year. Maximum 28 years. 5. Is there a specific “typical” project that exemplifies current whitetopping practice in your jurisdiction? 57% Yes. 43% No. 6. If yes to #5, please identify the location, date of construction, and performance of the project. If a report is avail- able with additional details, please provide a citation: • Colorado DOT: SH-83 (Parker Road)—Parker Road has had three thin whitetopping projects over 6 years; one project in Region 6, two in Region 1. The dates of construction were 1997, 1999, and 2002. All three projects were 5.5 to 6.0 in. thick, two with fibers; all have similar traffic and subgrade conditions. To date, two of three have excellent performance and one has very good performance. • Delaware DOT: We whitetopped an existing HMA ramp that came off an Interstate to an intersection. Portions of the panels have cracked and spalled due to an adjacent construction project where heavy trucks ran over the corners of the panels. • Georgia DOT: Our first UTW was 2.75 in. in an approach to a static scale in a truck weigh station on I-85 in Franklin County. This job was placed in 1993 and has served well. It was placed in an area of severe rutting of the asphalt that was being repaired every 6 months. The whitetopping had some minor repairs over the years due to cracked panels. All panels were 2 ft x 2 ft. This truck weigh station is being upgraded at this time and the UTW was removed in 12/02. We have four other jobs in the southern part of the state, also at intersections where heavy truck traffic was causing rutting and shoving of the asphalt. These have also performed well over the years with little repairs required. • Illinois DOT: State Highway System—US Highway 51 and Pleasant Hill Road in Carbondale. This project was con- structed in 1998 and unfortunately was removed this summer due to a realignment of US Highway 51 through Carbon- dale. Performance was very good prior to removal. Local Highway System—County Highway 3 between Louisville and Sailor Springs in Clay County. This project was also constructed in 1998 and performance has been very good to date. • Minnesota DOT: TH-30, Amboy. Constructed July 1993. Six 6-in.-thick whitetopping test sections. Very good perfor- mance after 9 years of service. Very low volume road, however. • Mississippi DOT: US-72 at Hinton Street in Corinth. Constructed in April 2001 with poor to satisfactory performance to date. Surface is too rough (IRI = 4.75 mm/m) and a couple of panel corner breaks will become a maintenance issue. Report available in the TRIS database (AN:00929214 “Construction, Testing, and Preliminary Performance on the Resin Modified Pavement Demonstration Project” Author: R.L. Battey). • Montana DOT: Contact Bob Weber or Craig Abernathy for more information. • South Carolina DOT: Location—Intersection of SC-707 and US-17, Myrtle Beach. Date of construction: Oct. 2000; Performance—Very good.

53 • Texas DOT: Intersections of LP250 with Garfield and Modkiff, Midland. Construction completed in the summer of 2001 with excellent performance so far. The only distress observed so far is minor cracking on some panels. Project consisted of removing existing asphalt and base to depth of 9 in., placed 7 in. of a TY B dense-graded mix, milled 1 in., placed 3 in. of UTW. Used quick setting concrete 3,000 psi in 24 h, 3 # of fiber/cy, 5% to 7% air entrainment. Carpet drag or rough broom finish. No technical report has been prepared for the project. • Virginia DOT (VTRC): Rte 29 NBL approximately 10 mi south of Charlottesville, July 1995. 2000 ft project, 2 lanes, 2-in., 3-in., and 4-in. thick sections. 800 ft of 2-in thick section was badly cracked, began spalling, and had to be removed. Two reports are available: Interim Report: Evaluation of the Initial Condition of Hydraulic Cement Concrete Overlays on Three Pavements in Virginia, M.M. Sprinkel and C. Ozyildirim, VTRC 99-IR3, April 1999. Final Report: Evalua- tion of Hydraulic Cement Concrete Overlays on Three Pavements in Virginia, M.M. Sprinkel and C. Ozyildirim, FHWA/VTRC 01-R2, Aug. 2000. • Wisconsin DOT: State Trunk Highway 82 in Adams County. Constructed in 2001. The performance to date is excellent. • ACPA—Illinois Chapter, Inc.: Piatt County near Monticello is typical. County job, 5-in. minimum thickness. The UTW projects have been an assortment. • ACPA—Missouri/Kansas Chapter: Intersection of College and Pflumm in Overland Park, Olathe, and Lenexa, Kansas (corner of all three cities). The project was constructed in 1996 and has performed well. There are a few cracked pan- els at the curb edge that need repair and a few out in the wheelpath that remain intact due to the fibers and bond. We can get pictures if needed. • ACPA—NE Chapter: The project is a New York State DOT whitetopping. It was an intersection at Waldon and Cen- tral Avenues and was constructed in 2002. The project was unique in that the contractor had to place new asphalt, then mill the depth of 2 in. and overlay the area with 4 to 5 in. of PCC pavement. The performance is adequate; however, there was minor cracking where the concrete was placed over the newly placed asphalt. In areas where there was suffi- cient existing asphalt, the concrete did not exhibit cracking. • ACPA—Utah Chapter: Location: SR-198 at Arrowhead Trail, Spanish Fork, Fall of 2002, Performance: Excellent to date. • F.A. Rohr Bach, Inc. (Contractor): Shortlidge Road, State College, Pennsylvania, July 2001. Project was designed as a 3-in. UTW overlay of a downgrade intersection approach. The project is being monitored. Cracks have developed along the longitudinal edges, but have not had an adverse effect on the performance of the overlay. The previous pave- ment had terrible washboarding and was milled and overlaid every 3 years. As long as the cracking does not cause fur- ther deterioration of the UTW, it would be successful. General Comments: • Colorado DOT: CDOT has two urban and one rural thin whitetopping projects along with test sections constructed in 1994 and 1990. • Georgia DOT: We currently have a project this year in Savannah, with 43,000 yd2, 4 in. thick, to be placed in inter- sections on SR-204. • Illinois DOT: A construction and early performance report is available for these and other projects in Illinois. T.J. Winkelman, Whitetopping Construction and Early Performance in Illinois, Illinois DOT, Bureau of Materials and Phys- ical Research Report No. 144, June 2002. • Maine DOT: Maine DOT is hopefully going to construct a 4 in. ultra-thin whitetopping later this year. The location is a busy intersection in Portland. Estimated quantity is nearly 400 yd3. • Michigan DOT: Michigan completed its only whitetopping project to date in 1999. The project involved four test sec- tions: 150 mm with fibers, 150 mm without fibers, 125 mm with fibers, and 75 mm ultra thin. The ultra thin is not a whitetopping, strictly speaking. It was over a composite pavement. • Minnesota DOT: For more information, see the 2003 TRB paper “Whitetopping and Hot-Mix Asphalt Overlay Treat- ments for Flexible Pavement: A Minnesota Case History,” by T. Burnham and D. Rettner. • Nebraska DOR: Whitetopping sections of the projects are intermittent and consist of 9-in. PCC over AC. AC thickness depended on how much milling was needed to match the required profile and elevation. • New York State DOT: NYSDOT has had good success with its UTW projects over the past 5 years. • Oklahoma DOT: Division II has done two whitetopping projects on US-69 because our asphalt overlays were not last- ing very long (4 years usually) and we were looking for something better. These two projects have been done with Divi- sion II maintenance of our roads, such as overlays, armor coats, and now whitetopping. Because our maintenance money is limited, these projects are small (first project was 1.5 mi long, second was 1.2 mi long). • South Carolina DOT: Four-inch UTW with 4-ft joint spacing. • Texas DOT: Overall, TxDOT is happy with UTW performance. • Utah DOT: All of our recent whitetopping projects have been UTW.

54 • Virginia DOT (VTRC): Whitetopping should not be placed at a thickness of 2 in. Thicknesses of 3 and 4 in. are per- forming well. Based on the project, whitetopping is not practical relative to asphalt at most locations because of the high cost and long lane closure time required for construction and curing. • ACPA—Illinois Chapter, Inc.: To say there is a general type of project is probably a misstatement. Every one of the projects seems to have its own unique aspects. These are detailed on the attached sheets. • ACPA—NE Chapter: This project was the first for the Port Authority of New York and New Jersey (PANYNJ) in the state of New Jersey. A larger one has been awarded by PANYNJ at JFK Airport in New York. That project has not started to date. • ACPA—Utah Chapter: This UTW was part of an asphalt contract. UDOT requested a change order to replace the inter- section with UTW. Project was on a 5% grade and exhibited AC ruts greater than 2.5 in. in places. All construction was completed in less than 1 week. PROJECT SELECTION 7. Rank the following criteria for their influence on the decision-making process for hot-mix asphalt pavement reha- bilitation strategies where whitetopping is a viable alternative. 1 = Strongly considered; 2 = Routinely considered; 3 = Occasionally considered; 4 = Rarely considered; 5 = Not/never considered. Initial cost Average 1.52 (Rank: 1-tied). Longevity (life) of “fix” Average 1.52 (Rank: 1-tied). Traffic control Average 1.71 (Rank: 3). Life-cycle cost Average 2.44 (Rank: 4). Improvement to smoothness Average 2.56 (Rank: 5). Improvement to texture (safety) Average 2.64 (Rank: 6). Geometric design Average 2.68 (Rank: 7). Agency experience Average 2.84 (Rank: 8). Contractor experience Average 3.48 (Rank: 9). Improvement to noise Average 3.72 (Rank: 10). 8. Do you run life-cycle cost analyses of whitetopping strategies? 27% Yes. 73% No. 9. If yes to #8, what is the basis for unit costs? Area (e.g., square miles) only 57%. Volume (e.g., cubic meters) 0%. Combination of area and volume 43%. 10. Do you consider surface preparation (e.g., milling) prior to placing the overlay as a separate pay item? 85% Yes. 15% No. Comments on Project Selection: • Georgia DOT: We core the existing pavement and evaluate the existing asphalt to determine thickness and quality. We mill off 4 in. and try to maintain at least 4 in. of asphalt for support. Requests are normally made by our maintenance department, about where asphalt problems are frequently occurring. • Michigan DOT: I was not involved in the design phase and therefore cannot answer all of these questions. I have only been involved to record construction information and monitor performance. • Nebraska DOR: Whitetopping is rarely considered as a rehabilitation strategy. • New York State DOT: Intersections and ramps that have rutting or shoving as their primary form of distress are primary candidates for UTW. • Oklahoma DOT: Our project was getting an asphalt overlay about every 4 years and we were looking for something that would last longer. The main problem with this road was rutting caused by all the truck traffic. Our traffic count is 16,200 vpd, with 35% trucks. These concrete whitetopping project costs are about twice as much as our asphalt over- lay would cost but if it lasts longer than 8 years then we are financially ahead. • South Carolina DOT: UTW is generally considered after HMA strategies have been repeatedly unsuccessful.

55 • Virginia DOT (VTRC): We are not using whitetopping for reasons cited in Question 6. In situations where rutting asphalt is a problem (some intersections and turning lanes), we are constructing a full-depth concrete pavement starting with the base. • ACPA—Missouri/Kansas Chapter: Most of our UTWs are at intersections where asphalt has historically not held up well (3-year overlay cycles). Many of the cities in the Kansas City area use UTW as a standard maintenance procedure for these intersections despite the remainder of their projects being asphalt. The initial cost of the UTW is substantially higher than an AC overlay (4–6 times), but most of the agencies feel a 12–15 year fix will warrant the added expense. • ACPA—NE Chapter: This area in Port Newark, New Jersey, has a tremendous amount of heavy truck traffic. This area contains numerous shipper terminals with containers coming and going. The PANYNJ has experienced many asphalt failures at numerous traffic lights in the area. • ACPA—NE Chapter: The NYSDOT Regional Maintenance Engineer wanted a longer term fix. • ACPA—Utah Chapter: UTW is a new process in Utah. Whitetopping (>4 in. is not), but nothing has been placed since the late 1980s. Have no idea why. Performance of whitetopping on Interstates throughout Utah has been excellent. Per- formance of UTW in Utah (oldest ones placed in 1999) has been excellent as well. Comes down to money. • F.A. Rohr Bach, Inc. (Contractor): Extensive effort needs to be made in determining the thickness of the existing road base, particularly at the lowest point of the UTW, as that is probably a water flow line and has had the least amount of overlay. DESIGN 11. What techniques are used to evaluate the existing hot-mix asphalt layer for use in whitetopping design? Visual inspection of condition 90%. Pavement management data 62%. Falling weight deflectometer (FWD) 45%. Rut measurements 76%. Lab testing of hot-mix asphalt 7%. Test Method: • Georgia DOT: Tensile None 0%. Other (please elaborate): • Colorado DOT: Cracking, in-place thickness, condition, etc. • Montana DOT: Cores. • South Carolina DOT: Visual inspection of pavement cores. • Texas DOT: Cores of existing pavement taken to determine depth and quality of various layers of the existing pave- ment structure. • Utah DOT: Cores. • Virginia DOT (VTRC): All answers apply to the 1995 installation. • ACPA—Illinois Chapter, Inc.: Cores. • ACPA—NE Chapter: Cores (thickness and subbase evaluation). • F.A. Rohr Bach, Inc. (Contractor): Cores (thickness). 12. What techniques are used to evaluate the existing support (subgrade/base) layers for use in whitetopping design? Visual inspection of condition 52%. Falling weight deflectometer (FWD) 45%. Rut measurements 24%. Lab testing of subgrade and/or subbase 17%. Test Method: • Colorado DOT: R-value and soil classification. • Maine DOT: Borings to subgrade. • Nebraska DOR: Moisture and density. None 14%. Other (please elaborate): • Colorado DOT: FWD or a layer analysis might be used for design. • Delaware DOT: Past experience. • Louisiana DOTD (LTRC): It is anticipated that in the near future FWD will be used for subbase evaluation and the DCP (dynamic cone penetrometer) will be used for base/subgrade evaluations. • Montana DOT: Some subsurface investigation (if needed).

56 • Wisconsin DOT: As-builts. • ACPA—NE Chapter: History. 13. What pre-overlay repairs are routinely conducted prior to whitetopping overlay placement? Pothole “filling” 21%. Subgrade repairs (full-depth patching) 28%. Crack sealing 10%. None 38%. Other (please elaborate) • Montana DOT: Full-depth PCCP at localized areas. • Nebraska DOR: Pavement repair would be performed. • South Carolina DOT: UTW is typically used where the pavement is rutted but not otherwise distressed. Conse- quently, if pre-overlay repairs are needed, the site is not a suitable candidate for UTW. • Virginia DOT (VTRC): None needed. 14. What surface preparation method or combination of methods is most commonly used prior to whitetopping over- lay placement? Milling (preceded by pre-overlay repairs) 27%. Milling (without pre-overlay repairs) 63%. Sweeping only 33%. Air blast 37%. Water blast 30%. None 3%. Other (please elaborate): • Louisiana DOTD (LTRC): We have used the above-mentioned methods. Currently we are just milling and sweeping. • Montana DOT: Vacuum sweepers. • New York State DOT: We sand blast clean any surface where residue builds up. • Oklahoma DOT: We mill existing pavement to eliminate ruts and help control yield. Also, this rough texture helps the concrete to bond to the asphalt and puts the neutral axis of the composite pavement in the asphalt section. • Virginia DOT (VTRC): Sweeping and spraying water on the milled surface. 15. How is traffic loading characterized for whitetopping overlay design? Equivalent single-axle loads (ESALs) 59%. Axle load spectra 0%. ADT and percent trucks 38%. Traffic/roadway loading classification 7%. Other (please elaborate): • Georgia DOT: Usually high truck traffic areas, low speed. • ACPA—Missouri/Kansas Chapter: Not usually considered for UTW. 16. How often are fibers specified for the whitetopping concrete? 64% Always. 32% Sometimes. 4% Never. 17. If applicable, what types of fibers have been specified for the whitetopping concrete? Synthetic monofilament 37%. Synthetic fibrillated 78%. Steel 7%. Synthetic/steel mixture (in same mix) 0%. Other (please elaborate): • Maine DOT: Polypropylene fibers. • Oklahoma DOT: 1.5-in. Fibermesh fibers. • Texas DOT: Polypropylene fibers. • Virginia DOT (VTRC): Steel would not be used again because it rusts away in cracks. • ACPA—Illinois Chapter, Inc.: New Strux 90/40, a Grace structural fiber.

57 18. What percent (%) of the projects employ “fast-track” (rapid strength) concrete mixtures? Average 52%. 19. If “fast-track” techniques are used, what criterion is used to open to traffic? Compressive strength 91%. Strength Average: 2,933 psi. Range: 2,000 to 4,000 psi. Third point flexural strength 5%. Strength Average: 350 (one respondent). Time from construction (age) 14%. Age Average 53 h. Range: 5 h to 7 days. Other (please elaborate): • Colorado DOT: Most of the fast-track concrete was accepted using the maturity method based on test slabs and compressive strength. • Louisiana DOTD (LTRC): New jobs will have a flexural strength requirement. 20. Are climatological factors (e.g., air temperatures) used in the whitetopping design procedure? 8% Yes. 12% Sometimes. 81% No. If so, how? • ACPA—NE Chapter: Mix design, maturity, and strength. 21. How deep are the saw cuts made? Average 30% slab thickness (transverse). (Note: 2 respondents noted “1 in.”). Average 30% slab thickness (longitudinal). (Note: 1 respondent noted “1 in.”). 22. Are the joints sealed? 16% Yes. 84% No. If so, what material is used for sealing? • Colorado DOT: Silicone joint sealer or preformed joint sealer (often used for fast track). • Michigan DOT: Hot-pour rubber. • Nebraska DOR: Hot pour. • Texas DOT: Class 5 joint sealant at construction joint. Sawcut joints are not sealed. 23. How are transitions made from the whitetopping to the adjacent pavement? Taper to a thickened concrete section 60%. Reinforced panels at transition 7%. Other (please elaborate): • Colorado DOT: Usually asphalt pavement was overlaid to bring level even with whitetopping. • Delaware DOT: Hot-mix wedge. • Georgia DOT: Have placed with and without thickened areas. • Oklahoma DOT: We start the project at the end of a bridge or concrete pavement and mill the full thickness of the whitetopping project at this location. • Virginia DOT (VTRC): Whitetopping was an inlay. • ACPA—Illinois Chapter, Inc.: AC fillet typically. Inlays just butt up to the existing asphalt. • ACPA—Missouri/Kansas Chapter: Most agencies forget about the thickened edge. 24. What are other design features or concrete-making materials unique to whitetopping overlays (compared to other concrete pavements in your jurisdiction)? • Michigan DOT: Our ultra-thin section was unsealed with 1 to 1.25 m joint spacing in both directions. We did not use dowel bars at the transverse joints in the regular whitetopping. We did use deformed tie bars in the longitudinal joints, however. • Mississippi DOT: Plastic spacers are utilized at the crosscuts. • Montana DOT: Fibers and at times cement types.

58 • Oklahoma DOT: We use 6 lb of Fibermesh fibers per yard of concrete and use our #67 rock due to the thinner pavements. • Virginia DOT (VTRC): 2-in.-thick sections done with 0.5-in. maximum size aggregate and 7.5 bags per cubic yard cementitious materials rather than the 1-in. maximum size aggregate and the 6.75 bags per cubic yard used in thicker sections. • ACPA—Missouri/Kansas Chapter: Most all of our UTWs have been constructed over a weekend so fast-track con- struction and high early-strength concrete employed. • ACPA—Oklahoma/Arkansas Chapter: Short joint spacing. • F.A. Rohr Bach, Inc. (Contractor): Aggregate size is reduced to 3/8 in. material. 25. What existing design procedure is used for whitetopping design (e.g., AASHTO 1993 guide) in your jurisdiction? Please identify the procedure and/or how to obtain a copy. • Arizona DOT: ACPA guide. • Colorado DOT: Guidelines for the Thickness Design of Bonded Whitetopping Pavement in the State of Colorado, Report No. CDOT-DTD-98-10. • Delaware DOT: We just went with 4 in. because we had a thick HMA pavement beneath the whitetopping. • Iowa DOT: AASHTO 1993, ACPA. • Illinois DOT: ACPA, Whitetopping—State of the Practice. • Louisiana DOTD (LTRC): FHWA-IF-02-045. • Maine DOT: None has been developed yet. • Michigan DOT: AASHTO 1993 guide. • Mississippi DOT: ACPA method. • Montana DOT: Seat-of-the-pants method. • Nebraska DOR: AASHTO. • South Carolina DOT: Thickness by policy only. Existing pavement must have at least 4 in. of asphalt after milling to be eligible for UTW. • Texas DOT: Whitetopping—State of the Practice, Engineering Bulletin EB210.02P, produced by the ACPA. • Utah DOT: ACPA guidelines. • Virginia DOT (VTRC): None. • Wisconsin DOT: We have been using PCA’s guidelines for design. We have also been using ISLAB 2000 for stress evaluation. • ACPA—Illinois Chapter, Inc.: We’ve used AASHTO 1993 guide. We have also used variations of the spreadsheets upon which the ACPA design procedure is based. I’ve also used adaptations of the work done by Scott Tarr, CTL, for Colorado and reported at the 2000 TRB annual meeting. • ACPA—Missouri/Kansas Chapter: Usually no design procedure. Most agencies just select a thickness between 3 and 4 in. • ACPA—NE Chapter: ACPA Win Pas and New York State Specification for HMA Overlays Utilizing PCC. Obtain a copy from NYSDOT website under Engineering Instructions/Specifications. • ACPA—Oklahoma/Arkansas Chapter: Win Pas (AASHTO 1993 based). • ACPA—Utah Chapter: We use ACPA UTW design calculator. Found on www.pavement.com. 26. What procedure is used for determining the joint spacing for whitetopping overlays? • Arizona DOT: ACPA/PCA guide. • Colorado DOT: Based on PCC pavement thickness. • Delaware DOT: ACPA recommendations—whatever the depth of placement (in feet). • Iowa DOT: Traditional rule of thumb; i.e., 2 in. thick use 2 ft x 2 ft, 3 in. thick use 3 ft x 3 ft. Also use experience from other projects like IA 21. The DOT has only had a couple projects. • Illinois DOT: The joint spacing (transverse and longitudinal) in feet is generally one to one and a half times the over- lay thickness in inches. Example: Overlay thickness = 3.0 in., joint spacing = 3.0 to 4.5 ft. However, we do try to avoid placing a longitudinal joint in the wheelpath or area of high stress. Also, we place full-depth joints over major cracks of the underlying pavement and at the boundaries of any patches that are placed in the underlying pavement. (These full- depth joints are sealed with a hot-poured joint sealant.) • Louisiana DOTD (LTRC): FHWA-IF-02-045. • Maine DOT: As per ACPA . . . 1 ft per inch of thickness. • Michigan DOT: Recommendations from ACPA. • Mississippi DOT: Early projects the same spacing, in feet as inches of thickness, was used (i.e., 4 in. thick = 4 ft x 4 ft panels). However, currently evolving to a spacing based on Minnesota DOT research that keeps the longitudinal joint out of the wheelpath. • Montana DOT: Current recommended whitetopping procedures, from ACPA and FWHA.

59 • Nebraska DOR: Whitetopping has been equal to or greater than 8 in. deep so joint spacing is the same as other pave- ment. • New York State DOT: Design guidance for UTW projects can be found in Engineering Instructions (EI) 01-008. All EIs can be found in the department’s website under Publications. • Oklahoma DOT: Our joint spacing is 1 ft for every inch of thickness. • South Carolina DOT: Policy, previous experience. • Texas DOT: Joint spacing in feet equal depth of slab in inches. • Utah DOT: 12 times thickness (inches). • Virginia DOT (VTRC): Spacing is 12 times the thickness rounded to a number that divides evenly into the lane width. • ACPA—Illinois Chapter, Inc.: Seat of the pants and experience. • ACPA—Missouri/Kansas Chapter: Usually the general rule of 12 times the thickness is used in conjunction with lane widths. • ACPA—NE Chapter: 1 to 1.5 times thickness. • ACPA—NE Chapter: ACPA guidelines and NYSDOT Specifications for HMA Overlays Utilizing PCC. Typically the thickness will determine the joint spacing. • ACPA—Oklahoma/Arkansas Chapter: 4 ft to 6 ft for 4-in. UTW, pavements of 4 in. same as normal pavements. • ACPA—Utah Chapter: Not a procedure. Go off recommended guidelines from ACPA. • F.A. Rohr Bach, Inc. (Contractor): 3 ft centers rule of thumb. 27. If you have been involved in developing or evaluating a new design or analysis procedure for whitetopping, please provide details on how to obtain additional information. • Arizona DOT: ACPA/PCA. • Georgia DOT: Typically use #7 (1/2 in.) max size stone. • New York State DOT: There are no plans to revise the current design and construction procedures. • ACPA—Illinois Chapter, Inc.: Not been involved, but would sure like to try something more rational. Currently inves- tigating ISLAB 2000 adaptations. Comments on Design: • ACPA—Illinois Chapter, Inc.: Do not have a good procedure for working on top of mixed surfaces. We have several that have combinations of exposed concrete as a direct or partially bonded system combined with UTW. Seems to work okay so far, but has me jumpy based on past experience. • ACPA—Missouri/Kansas Chapter: 3 to 4 in. appears to be a good thickness for most applications. CONSTRUCTION 28. If fibers are introduced into the concrete mixture, how is this done? Pre-mixing with dry constituents 8%. Adding to wet mixture via bags/bundles 68%. Adding to wet mixture via loose fibers 16%. Other (please elaborate): • Iowa DOT: Blown into drum, wet mixture. • Michigan DOT: Not known how the contractor accomplished this. • Montana DOT: Added to empty drum with small amount of water, and then add the dry constituents. • South Carolina DOT: Method left to concrete producer. • ACPA—Missouri/Kansas Chapter: Have had problems with fibers balls. 29. Is batching or transportation of concrete for whitetopping overlays done differently than for other concrete paving? If so, please explain how it is different. 18 Respondents answered “No.” • Maine DOT: Batching will be done as our concrete bridges are done. • South Carolina DOT: UTW is brought in agitator/mixer trucks; dump trucks not allowed. • Utah DOT: Typically UTW projects are serviced by traditional ready-mix operations, whereas most conventional PCCP projects are serviced by portable pre-mix plants and non-agitating haul trucks. • ACPA—Illinois Chapter, Inc.: Not done differently so far. We’ve used central mix for the big jobs and transit for the small ones. • F.A. Rohr Bach, Inc. (Contractor): Batch loads are smaller (6 to 7 cy) to allow for quick discharge to ensure that slump is not lost.

60 30. Is placing the concrete for whitetopping overlays done differently than for other concrete paving? If so, please explain how it is different. 12 Respondents answered “No.” • Georgia DOT: Use of small vibratory screeds. • Iowa DOT: No belt placer. • Illinois DOT: Standard concrete paving is performed with a mechanical concrete placer followed by a mechanical slip-form concrete paving machine. These machines use a string line to achieve grade control and smoothness. The main-line whitetopping (thin) that we have done was placed in this fashion. However, all of our intersection projects (ultra-thin) have used 2 × 4 lumber as formwork and a vibratory screed for finishing. The concrete is manually placed in front of the vibrator screed. • Maine DOT: Maine has no new concrete pavements. This will likely be laser screeded or vibratory screeded. • Michigan DOT: The only difference is that the existing surface was pre-wet prior to concrete placement. • Mississippi DOT: Usually a paver is not used and unfortunately bull floats are utilized for the surface finish, thus leading to a poor ride quality on most projects. • New York State DOT: Typically, because of room constraints smaller paving equipment is utilized to place the PCC. • Texas DOT: Our limited experience is that a different type of screed is used for the UTW. Other than that, the paving operation is very similar to concrete pavement. • Utah DOT: UTW lends itself to hand placements rather than slip-form operations. • Virginia DOT (VTRC): Whitetopping is done one lane at a time. Full-depth pavements are often constructed over multiple lanes. • ACPA—NE Chapter: Yes, we have a couple of different processes for placement. One contractor has a Zero Clear- ance paver for slipforming whitetopping; others have used roller screed and air “truss” screeds. • F.A. Rohr Bach, Inc. (Contractor): Much more hand screed to create swale lines. Much more manpower required on a per cubic yard basis. 31. Is finishing and curing the concrete for whitetopping overlays done differently than for other concrete paving? If so, please explain how it is different. 14 Respondents answered “No.” • Georgia DOT: Broom finish in lieu of tining. Same curing. • Maine DOT: Only a curing compound will be specified on this project. • Montana DOT: Adding more curing compound (double dose). • ACPA—Illinois Chapter, Inc.: Sometimes will insist on double coat of curing compound on the thinner sections. • ACPA—Missouri/Kansas Chapter: Special attention is paid to the timeliness of curing and the application is usu- ally increased to 1.5 to 2 times. • ACPA—NE Chapter: We specify a double coverage of curing. • ACPA—Oklahoma/Arkansas Chapter: Double application rate of curing compound. • ACPA—Utah Chapter: Apply the curing compound at twice the rate of normal paving and get it on rather timely. Sawing in a timely manner. • F.A. Rohr Bach, Inc. (Contractor): Time is accelerated. Immediately after strike-off it is finished and immediately it is spray cured. Poly covers/wetting is done after sawcutting. 32. Is saw cutting the concrete for whitetopping overlays done differently than for other concrete paving? If so, please explain how it is different. 6 Respondents answered “No.” • Colorado DOT: More often have had to use Soff-Cut saws to prevent premature crack formation, particularly in fast-track sections. • Delaware DOT: Yes—just earlier. • Georgia DOT: Use of lightweight saws to make sure joints are sawed before cracking can occur. • Illinois DOT: Yes. Early entry (lightweight) saws are used to cut the joints as soon as the concrete will support the weight of the saw and operator. Care is taken to avoid premature sawing and spalling of the joints. • Michigan DOT: The joints widths were 3 mm using one-stage sawcutting. Typically, we use two-stage sawcutting (relief cut followed by a final width cut). • Montana DOT: No, using early entry saws. • New York State DOT: We only do a single stage sawcut (T/4) for both longitudinal and transverse sawcuts. • Oklahoma DOT: We saw more joints and do not seal them. • South Carolina DOT: Early entry saws required. • Texas DOT: The sawcutting is done as soon as possible without damaging the surface.

61 • Utah DOT: Sometimes the contractor chooses early entry saws for UTW. • Virginia DOT (VTRC): Yes, whitetopping gets 1-in. soft cut; full-depth pavement gets hard cut approximately one- third the thickness of the pavement. • Wisconsin DOT: Yes on whitetopping we are using a soft cut saw. • ACPA—Illinois Chapter, Inc.: UTW is cut using early entry saws. Most of the other conventional whitetopping has used regular saws. • ACPA—Missouri/Kansas Chapter: Usually early entry saws are used, and a lot of them. • ACPA—Oklahoma/Arkansas Chapter: More saws due to smaller sawing window on UTW. Early entry saws are contractor’s option. • ACPA—Utah Chapter: Just done a bit quicker with higher cementitious mixes. • F.A. Rohr Bach, Inc. (Contractor): Early cut saws are used instead of traditional wet cut saws. 33. Is quality control of the concrete used in the whitetopping overlays different than for other concrete paving? If so, please explain how it is different. 20 Respondents answered “No.” • Louisiana DOTD (LTRC): No, not at this time. Future jobs will involve flexural strength testing for mix approval in the preconstruction phase of the job. • Maine DOT: Quality control will be increased due to the experimental nature and critical location. • South Carolina DOT: PCC controlled by compressive rather than flexural strength. • F.A. Rohr Bach, Inc. (Contractor): Much more attention has to be given to every aspect of the application. White- topping can be very challenging. 34. If you have a standard specification or special provision for whitetopping construction, please attach a copy or describe how to obtain (e.g., Internet address). • Arizona DOT: No standard specification. • Colorado DOT: [Online]. http://www.dot.state.co.us/DesignSupport/Construction/1999SSP/412pccp.doc. • Delaware DOT: Contact Specification Engineer—George Nagase (302-760-2252). • Illinois DOT: Yes, attached are two special provisions for whitetopping overlays. One is typical of a mainline applica- tion and the other is typical of an intersection application (available from synthesis author if requested). • Louisiana DOTD (LTRC): See attachment and Please Note! This is a draft copy and not finalized but indicates the direc- tion LA DOTD is going. • Maine DOT: See attached (available from synthesis author if requested). • Michigan DOT: We do not have a standard specification yet. • Mississippi DOT: Yes, will attach (available from synthesis author if requested). • Montana DOT: Current industry standard (ACPA/FHWA). • Nebraska DOR: None. • New York State DOT: We have a special specification that we used. It can be found on the website with the EI. • South Carolina DOT: Copy attached (available from synthesis author if requested). • Texas DOT: We are in the process of developing a statewide special specification for UTW. • Virginia DOT (VTRC): No. • Wisconsin DOT: No. • ACPA—Illinois Chapter, Inc.: Will attach (available from synthesis author if requested). • ACPA—Missouri/Kansas Chapter: We have a new APWA Metro specification for Kansas City, which includes UTW. Both MoDOT and KDOT also have specifications. • ACPA—NE Chapter: 18502.0601 M—Thin Portland Cement Concrete (PCC) Overlay of Hot Mix Asphalt (HMA) Sur- faced Pavement, Unprofilographed. 18502.0602 M—Thin Portland Cement Concrete (PCC) Overlay of Hot Mix Asphalt (HMA) Surfaced Pavement, Unprofilographed, High Early Strength Mix [Online]. http://dotweb1.dot.state. ny.us/specs/wpdindex18.html. • ACPA—Utah Chapter: UDOT is currently revising their UTW specification. You can try (if available) [Online]. www.udot.utah.gov. Comments on Construction: • Colorado DOT: Construction has been similar to normal concrete sections. • New York State DOT: See the EI. • Virginia DOT (VTRC): No problems.

62 • F.A. Rohr Bach, Inc. (Contractor): Opening to traffic is an issue. Specifications must clarify the method used to de- termine strength. I do not believe traditional cylinders are appropriate as a measure of field cure/opening to traffic. Maturity testing should be considered on UTW projects. PERFORMANCE, REPAIR, AND REHABILITATION 35. For each distress type, please identify how often it is encountered on whitetopping overlays that you have observed: 1 = Commonly observed; 2 = Occasionally observed; 3 = Rarely observed; 4 = Never observed. UTW TWT [≤100 mm (4 in.)] [>100 <200 mm (>4 <8 in.)] Corner cracking—wheelpath only Avg. 2.10 (Rank: 1) Avg. 3.25 (Rank: 2) Corner cracking—not in wheelpath Avg. 2.65 (Rank: 2) Avg. 3.50 (Rank: 5) Transverse cracking—wheelpath only Avg. 2.85 (Rank: 5) Avg. 3.58 (Rank: 6) Transverse cracking—full lane width Avg. 3.00 (Rank: 7-tie) Avg. 3.42 (Rank: 3-tie) Longitudinal cracking—wheelpath only Avg. 2.80 (Rank: 4) Avg. 3.62 (Rank: 7) Longitudinal cracking—not in wheelpath Avg. 2.90 (Rank: 6) Avg. 3.42 (Rank: 3-tie) Shattered slab—wheelpath only Avg. 3.00 (Rank: 7-tie) Avg. 3.92 (Rank: 10-tie) Shattered slab—not in wheelpath Avg. 3.20 (Rank: 9) Avg. 3.92 (Rank: 10-tie) Joint spalling Avg. 2.70 (Rank: 3) Avg. 3.08 (Rank: 1) Polishing of aggregates Avg. 3.80 (Rank: 11) Avg. 3.83 (Rank: 8-tie) Rapid deterioration of smoothness Avg. 3.40 (Rank: 10) Avg. 3.83 (Rank: 8-tie) Other (please elaborate)—UTW: • Texas DOT: 3. • Virginia DOT (VTRC): Spalling of 2-in. thick sections. • ACPA—NE Chapter: 2—Circular cracks, four panels. • F.A. Rohr Bach, Inc. (Contractor): 2—faulting due to thin paving subsupport. Other (please elaborate)—TWT: • Colorado DOT: One 1997 project has some longitudinal cracking of a construction problem. Most of the other proj- ects are too young to show much distress. The test sections built in 1990 are showing their age, and some will have to be addressed soon. • Virginia DOT (VTRC): Not used. • ACPA—NE Chapter: 2—Circular cracks, four panels. 36. If applicable to your experience, please identify for each repair technique how often it is employed (when needed) on existing whitetopping overlays: 1 = Commonly used for repair; 2 = Occasionally used for repair; 3 = Rarely used for repair; 4 = Never used for repair. UTW TWT [≤100 mm (4 in.)] [>100 <200 mm (>4 <8 in.)] Full slab replacement Avg. 3.40 (Rank: 1) Avg. 3.20 (Rank: 1) Partial slab replacement Avg. 3.64 (Rank: 3) Avg. 3.56 (Rank: 2) Crack sealing Avg. 3.86 (Rank: 5) Avg. 3.70 (Rank: 4) Joint (re-)sealing Avg. 3.79 (Rank: 4) Avg. 3.60 (Rank: 3) Spall repair Avg. 3.57 (Rank: 2) Avg. 3.89 (Rank: 5-tie) Dowel bar retrofit Avg. 4.00 (Rank: 7-tie) Avg. 3.89 (Rank: 5-tie) Tie bar retrofit Avg. 4.00 (Rank: 7-tie) Avg. 3.89 (Rank: 5-tie) Diamond grinding Avg. 3.93 (Rank: 6) Avg. 3.89 (Rank: 5-tie) Other (please elaborate)—UTW: • Louisiana DOTD (LTRC): 4. • Texas DOT: 3.

63 • Virginia DOT (VTRC): 4. • ACPA—NE Chapter: 4. Other (please elaborate)—TWT: • Colorado DOT: Most of CDOT’s projects are young, so distresses are minimal at this time. • Virginia DOT (VTRC): None used. • ACPA—NE Chapter: 4. 37. When a whitetopping overlay has/does reach the end of its life, what options have been/will be considered? 1 = Only option considered; 2 = Strongly considered; 3 = Possibly considered; 4 = Rarely considered; 5 = Not/never considered. UTW TWT [≤ 100 mm (4 in.)] [>100 <200 mm (>4 <8 in.)] Remove and replace with new Avg. 3.36 (Rank: 2) Avg. 3.11 (Rank: 2) whitetopping Remove and replace with other than Avg. 3.00 (Rank: 1) Avg. 3.33 (Rank: 3) whitetopping Overlay old whitetopping Avg. 3.43 (Rank: 3) Avg. 3.00 (Rank: 1) Break/seat/overlay old whitetopping Avg. 4.29 (Rank: 4) Avg. 4.13 (Rank: 4) Other (please elaborate)—UTW: • Montana DOT: Too soon to tell. • New York State DOT: Reconstruct. • Texas DOT: 4. • Virginia DOT (VTRC): 5. • ACPA—Missouri/Kansas Chapter: Have not reached end yet. • ACPA—NE Chapter: 2—Reconstruct. • ACPA—Oklahoma/Arkansas Chapter: If DOT and pavement conditions allow, bonded overlay. • F.A. Rohr Bach, Inc. (Contractor): 2—Full-depth reconstruction. • Montana DOT: Too soon to tell. Other (please elaborate)—TWT: • Montana DOT: Too soon to tell; undecided. • Virginia DOT (VTRC): Not used. • ACPA—NE Chapter: Diamond grind. • ACPA—NE Chapter: 2—Reconstruct. 38. Is there a pre-defined schedule for the various repair and rehabilitation activities listed here? If so, please describe the process and/or identify how a copy might be obtained. 15 Respondents answered “No.” • ACPA—Illinois Chapter, Inc.: Typically in terms of cracked slabs, which is actually too conservative. Shattered slabs would make more sense since a cracked slab frequently remains keyed in or sometimes bonded but with inter- mediate random cracks. Side note: In several cases, I have seen bonded overlays that have delaminated that will still provide several years of performance, although DOT will rate them as failed panels since they have cracked. Need a more realistic definition of failure. • ACPA—Missouri/Kansas Chapter: We have not really done any repairs to our UTWs. Most have some cracking, but it appears to be remaining tight and has not affected roughness or performance yet. 39. How is performance of a whitetopping overlay defined? Are there methods in place to measure or evaluate the per- formance? If so, please describe. • Arizona DOT: Projects still under design. Construction later this year. • Colorado DOT: The Pavement Management Annual Survey of pavement condition is one of the main tools for evalu- ation at this time. • Delaware DOT: Not available—visual. • Georgia DOT: Service life. • Iowa DOT: By amount of cracking and debonding. No formal method to measure performance.

64 • Illinois DOT: Visual distress surveys performed on an annual basis. The amount of cracking and distress is tracked over the course of the project. • Louisiana DOTD (LTRC): No. • Maine DOT: Reduction of pavement rutting. • Michigan DOT: Yearly visual evaluation for distress, yearly FWD testing, yearly smoothness testing. • Minnesota DOT: Visual distress (cracking) and ride smoothness. • Mississippi DOT: MDOT Pavement Management Distress Criteria based on the SHRP LTPP Distress Identification Manual. • Montana DOT: Crack mapping, delamination/debonding, visual only. • Nebraska DOR: Performance is measured the same as other rigid pavement. • New York State DOT: All of the UTW projects are performing well. Rutting and shoving have been eliminated and the traveling public is now assured of a smooth, long lasting ramp or intersection. • South Carolina DOT: Periodic visual inspection is conducted on the projects completed to date. • Texas DOT: The amount of time that it performs under traffic with no repairs needed. We have no formal methods in place to measure or evaluate the road other than visual observation. • Virginia DOT (VTRC): Good, means it has not spalled away. • Wisconsin DOT: Performance is defined by our Pavement Management System. • ACPA—Illinois Chapter, Inc.: Not one of which I am aware. • ACPA—Missouri/Kansas Chapter: Typical methods, visual survey plus ride quality. • ACPA—NE Chapter: Just standard pavement management practices. Typically a windshield survey followed by FWD if needed. • ACPA—Oklahoma/Arkansas Chapter: If it lasts a year or longer without severe rutting/shoving then we have been suc- cessful. No methods in place to evaluate performance other than visual observation. • ACPA—Utah Chapter: UDOT has defined as such. 40. Is there a method in place to measure or evaluate the remaining life of a whitetopping overlay? If so, please describe: 13 Respondents answered “No.” • Arizona DOT: Visual field review and cores. • Colorado DOT: The pavement management remaining service life curves. • Maine DOT: Visual inspection. • Michigan DOT: Michigan has remaining service life using distress data from our Pavement Management System. This typically requires historical data, however. We have no historical data on whitetopping, so my answer would be “no” for our one project. • Nebraska DOR: Same as other rigid pavement. • ACPA—Illinois Chapter, Inc.: Full-depth patching of the sections of UTW for which there were problems. Comments on Performance, Repair, and Rehabilitation: • Georgia DOT: Our UTW has performed well with minimal repairs. Need to be sure when milling that thin “scab” lay- ers of asphalt are removed and that the underlying layer is not prone to stripping, since our joints are not sealed. • Michigan DOT: No repairs have been done on our whitetopping project (Question 36) except for a situation where two panels in the UTW were removed to repair a water main leak. The panels were removed full depth and replaced with concrete. • Mississippi DOT: Most problems in UTW in Mississippi have stemmed from stripping in the underlying HMA, result- ing in a loss of bond with the concrete and ultimately failure of the UTW. • Nebraska DOR: The asphalt layer appears to trap moisture and increase aggregate–alkali reactivity. • Oklahoma DOT: Our first whitetopping project is 18 months old with no repairs or failures to date. Our newest white- topping project was completed in December 2002 with no repairs or failures to date. • South Carolina DOT: The greatest problem we have had with UTW has been the nonuniform nature of pavement thick- ness in urban settings where the need for UTW is highest. Consequently, despite extensive preconstruction coring, we have encountered areas of low asphalt thickness. These areas do not provide adequate support for the UTW and rapid deterioration is observed. Because of this difficulty, our agency will be using UTW only for special situations and not as a routine procedure. • ACPA—Missouri/Kansas Chapter: Again, have not really had to do much UTW repair to date. Probably will be com- ing soon. • ACPA—Oklahoma/Arkansas Chapter: Out first UTW was a 4 in. intersection overlay. Will be 5 years old this summer and has performed remarkably. Only a few minor distresses observed. Has been in place long enough that engineers/

65 owners convinced of long-term performance. Expect more to follow soon. Our second attempt is a UTW/TWT hybrid: 4 in. inside lane and 6 in. outside lane. Has performed so well in first year that owner has already produced second iden- tical project. • ACPA—Utah Chapter: Again, Utah is relatively inexperienced with UTW. Our oldest projects were built in 1999 and are still performing excellently. UTW has been used only in intersection applications in Utah. Whitetopping (difficult to find the information and everyone seems to have forgotten about it) is performing well. For some reason our state does not maintain PCC pavement and just lets them go. The one whitetopping (10.5 in.) I am aware of has exhibited corner breaks and exhibits faulting. UDOT has programmed in to rehab this pavement in the next 5 years.