High Performance PMA Applications for Extreme Stress. NASCAR Race Track Paving

Transcription

1 High Performance PMA Applications for Extreme Stress NASCAR Race Track Paving

2 Acknowledgements Association of Modified Asphalt Producers Bob Rivers Valero Energy Corporation Kim Stokes

3 Brief History Charlotte Motor Speedway turns 3 & degree banking, facing south Surface temperature of 140 o F w/o traffic + Existing mix high in asphalt content w/ fibers + Gravity = Mix melting and flowing downslope

4 Brief History Added about 6% Shell Krayton to AC-20 Ring and ball softening of 180 o F Removed existing mix and placed 2.5 of ¾ mix followed by 1.5 of ½ mix Placed at 300 to 325 o F Compacted at 280 o F or higher 92% to 95% of lab-compacted density

5 Brief History The next month paved North Carolina Motor Speedway without the polymer The following month paved Atlanta Motor Speedway with the polymer So, 3 tracks in 3 months, 2 with and 1 without Less stripping and wear with polymers Elasticity helps with embankment movement and settlement

6 Infineon Raceway (Sears Point) Reconstruction of the Chute, turns 4 to 7, in 2001 Existing ½ mix Replaced most of the natural sand with manufactured sand for stability and tooth Client wanted to stay with AR binders Had good experience with 8000 & Track subgrade very weak and wet Had to get compaction without destroying track Used AR 4000 for tack

7 Infineon Raceway (Sears Point) Reconstruction of the Chute, turns 4 to 7, in 2001 Performance generally good, compared to past surfacing Prone to raveling in weak areas Joints Hand work

8 Infineon Raceway (Sears Point) Go Cart track and miscellaneous areas in 2002 Similar local mix Very little natural sand Talked client into polymer PG76-22 with about 5% elastomeric polymer from Valero (Huntway)

9 Infineon Raceway (Sears Point) Good results Mix was workable Pavement performed better than previous surfacing Weak areas (joints, handwork) still prone to raveling

10 Infineon Raceway (Sears Point) Overlay of about 70% of the track in 2003 Wanted to maximize results Prequalify competitive bidders to insure best value Written specifications and formal bid package Natural sand limited to 8% Polymerized binder required

11 Bidder Prequalification Met individually with each prospective contractor for one hour prior to bid. General project description Key areas of concern Identification of key personnel Discussion of contractor and producer quality control

12 Bidding Low bid from one of the top-ranked contractors based on the prequalification interview Ghilotti Construction Company. Syar Industries supplied the mix and Quality Control. Ghilotti had paved the other areas of the track

13 Mix Design Requirements Caltrans ½ Maximum, Medium grading 100% fracture (except for natural sand) Natural sand limited to 8%, and to be used only to eliminate humps or sags in the gradation PG with SBS or SBR modification required Design per Caltrans 367 except target air voids of 2% to 3% based on Rice Test section required to satisfaction of Engineer

14 Quality Control Requirements Provided by Producer (Syar Industries) Mix design Certificates of compliance Hot bin gradations Asphalt contents and gradations by ignition Laboratory-compacted specific gravity Rice specific gravity Laboratory air voids Hveem Stabilometer Field compaction nuclear gauge with core correlation

15 Track Preparation Existing cracks routed and cleaned Hot-pour crack sealant used Recessed ¼ to 3/8 below track surface No overband allowed On steep grades, hot fines were blade laid and/or hand tamped into cracks

16 Track Preparation 3

17 Equipment Requirements Echelon paving required Written into specifications Maximum distance between pavers 75 Pneumatic-tire roller required Surface kneading for texture Helps break in the track while hot Helps reduce raveling Improved compaction on irregular areas

18 Ride Quality Requirements California Profilograph before and after, following the racing line Finished profile index not to exceed one-half of the original

19 Compaction Requirements Test strip to prove methods Mat 6 or more away from longitudinal joint: 95% of Rice or greater Nuclear gauge correlated to cores Longitudinal joints: 93% of Rice or greater Cores taken directly on the joint

20 Other Requirements Cold milled tapers at joints Failed areas removed and replaced AR-4000 tack 1.5 leveling course over about ½ the area Improve ride quality Provide structural improvement

21 The Goals Wanted a durable mix Easily compacted Avoid subgrade damage Better durability Tight surface with good traction For surface tenacity and durability wanted as much asphalt as possible

22 Oakland Box Test Oakland Box Test If the box sticks, you have too much asphalt

23 Oakland Comb Test Alternate method uses comb

24 Oakland Rat Test Not Recommended Use of rats is discouraged!

25 Equipment Used 11

26 Pavers: Cat 1055B s with skis, bottom dumping

27 Windrow: Paving Trucks only on Trucks track only to on dump track to dump 10

28 Mix Delivery: 330 to 340 o F 10

29 Paver Speed: 10 fpm or less, 280 tph 6

30 Pavers: built out to 20 Bin for Mesquite charcoal less dragging, pleasant aroma

31 Rollers: Cat 634C s for breakdown, a third for finish

32 Rollers: Cat 360B intermediate (no ballast)

33 Breakdown Close to Pavers 6

34 Breakdown Close to Pavers 10

35 Pneumatic: As close as possible w/o pickup (220 o F) 11

36 Pneumatic: As close as possible w/o pickup 11

37 Rollers: 50 fpm, or 0.6 mph 10

38 How d we do? Mix had some problems Power fluctuation dumped binder into mix Missed at plant Hauled to project Placed Coldmilled next day Gradations started to wander Fines bin had no baffle, so segregated Volumetrics, stability OK

39 How d we do? Compaction Consistent At or above target Joints indistinguishable from rest of mat

40 How d we do? Ride quality improved About half the track: less than half previous profile index The other half: about 2/3 previous index

41 Horizontal and vertical alignment not compatible with profilograph 6

42 But really, how d we do? Memo Gidley in a 1987 vintage Winston Cup stock car: The new surface will make times a lot faster, especially when it gets more rubber. Even out of the racing line, the surface is pretty consistent. Especially being new, its got really good grip. I think it will generate a lot more traction than ever before. Courtesy Infineon Raceway Archives

43 But really, how d we do? David Stanton, veteran motorcycle rider: Now, instead of being a one or two-line track, you have the possibility of having three or four lines, which adds another dimension to the track. I was anticipating a good track, but not this good. It far exceeded my expectations. The traction in Turn 2 was much higher than I ve ever experienced. Courtesy Infineon Raceway Archives

44 But really, how d we do? Jere Starks, Vice President on Facilities and Construction, Infineon Raceway: Thanks for all your help. We did a great job according to all reports.

45 Questions? MODIFIED ASPHALT PRODUCERS