Caltrans HMA Type C
CalAPA Fall Conference
24 October 2013
Skip Brown
Asphalt Consulting Services
Sacramento, CA
Presentation Overview
What?
 Why?
 Where?
 How?
 Local Successes

Caltrans HMA Type C –
What’s in a name? AKA …
 High

Stability
 Intersection
 Desert
What?
Type A … on steroids
 Rut resistant mix made with similar
components as Type A, BUT with
minor changes in the aggre...
What?


Type C
 higher stability than conventional Type A
 3 Mix choices: 1-inch, ¾-inch, ½ -inch
 Mix choice CRITICAL...
What?


Modified Compaction with CA

Kneading Compactor
 150 tamps at 230ºF
 500 additional tamps at 140ºF
 Stability
...
What? Type A vs Type C
(½-inch Mix)
Sieve Size

Type A

Type C

¾-inch
½-inch

100
95-99

100
90-98

⅜-inch
No. 4
No. 8
No...
What? Type A vs Type C
Mix Design Data - Example
Property

Type A

Type C

OBC (% dwa)

5.5

4.9

Air Void Content (%)

4.0

4.0

4.0

39

≥37
≥3...
Why?

Bradshaw Rd off-ramp
Highway 50 (WB)
¾-inch, Type A, AR-8000
8-years after placement

More than 1-inch of rutting!
Where?









Intersections
 Ticket Booths
Bus Stops
 Ready-Mix Plants
Toll Facilities
 HMA Plants
Haul Roads
...
How? – Mix Design


Mix Designation
1-inch
 ¾-inch
 ½-inch




Aggregate Crushed Particles
Aggregate Size

Coarse
(2 ...
How? Mix Design


Binder
Recommend “harder” binder, ie, Grade “bump”
 Central Valley – PG 70-10 (rather PG 64-10)




...
Impact of Aggregate Size
on Lift Thickness
½-inch

Type C

Tolerance
TV ±

¾-inch

100

─

½-inch

90-98

6

⅜-inch

64-86...
Nominal Maximum Aggregate Size (NMAS)
(one size larger than the first sieve to retain more than 10%)

⅜-inch
mix

100
100
...
What? Type A vs Type C
(½-inch Mix)
Sieve Size

Type A

Type C

¾-inch
½-inch

100
95-99

100
90-98

⅜-inch
No. 4
No. 8
No...
Construction Considerations


Ratio of Lift Thickness (LT) to NMAS






Maintain LT/NMAS of 4:1

Segregation ** – doe...
Improper handling and/or placement can cause
segregation resulting in raveling.
Paver with Slides inserted over Wings
The WRONG way

The RIGHT way
Effective Way to “Pinch”
and Roll a Cold Joint
Local Successes




Highway 50 Ramps
I-80 at Yolo Causeway
Local Agencies
Sac County (Watt Ave)
 Roseville (Sierra Col...
Watt Ave & Folsom Blvd




Traffic – Very Heavy w/ High Truck Volume
Teichert Mix Design - ½-inch Type C
Watt Ave ½-inch Type C
Watt Ave Number 2 Lane
½-inch Type C Mix
After 4 Years
< ¼-inch rutting

No rutting in any other lanes!
Review - HMA Type C











AKA High Stability, Intersection, Desert
Rut Resistant Mix
Slow Moving & Standing ...
QUESTIONS?
Your 1-stop shopping resource

www.calapa.net
Upcoming SlideShare
Loading in …5
×

Skip Brown

408 views

Published on

Presentation by Skip Brown of Asphalt Consulting Services on "Intersection Mix" aka "Type-C or High-Stability Mix delivered at the CalAPA Fall Asphalt Pavement Conference Oct. 24, 2013 in Sacramento, Calif.

Published in: Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
408
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
11
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Skip Brown

  1. 1. Caltrans HMA Type C CalAPA Fall Conference 24 October 2013 Skip Brown Asphalt Consulting Services Sacramento, CA
  2. 2. Presentation Overview What?  Why?  Where?  How?  Local Successes 
  3. 3. Caltrans HMA Type C – What’s in a name? AKA …  High Stability  Intersection  Desert
  4. 4. What? Type A … on steroids  Rut resistant mix made with similar components as Type A, BUT with minor changes in the aggregate structure and stiffer binder 
  5. 5. What?  Type C  higher stability than conventional Type A  3 Mix choices: 1-inch, ¾-inch, ½ -inch  Mix choice CRITICAL as it determines minimum lift thickness
  6. 6. What?  Modified Compaction with CA Kneading Compactor  150 tamps at 230ºF  500 additional tamps at 140ºF  Stability  Initial – ≥ 37  Modified – ≥ 35
  7. 7. What? Type A vs Type C (½-inch Mix) Sieve Size Type A Type C ¾-inch ½-inch 100 95-99 100 90-98 ⅜-inch No. 4 No. 8 No. 30 No. 200 75-95 55-66 38-49 15-27 2-8 64-86 42-57 29-39 13-19 3-7
  8. 8. What? Type A vs Type C
  9. 9. Mix Design Data - Example Property Type A Type C OBC (% dwa) 5.5 4.9 Air Void Content (%) 4.0 4.0 4.0 39 ≥37 ≥37 41 ≥35 68 65 – 75 60 – 70 Initial Stability 37 Modified Stability VFA (%) 72 Spec Note – Caltrans recommends selecting binder content at 5% air voids for Central Valley and Desert.
  10. 10. Why? Bradshaw Rd off-ramp Highway 50 (WB) ¾-inch, Type A, AR-8000 8-years after placement More than 1-inch of rutting!
  11. 11. Where?        Intersections  Ticket Booths Bus Stops  Ready-Mix Plants Toll Facilities  HMA Plants Haul Roads  Quarries Landfills  Recycle Yards Airports High Traffic Roadways Slow moving or Standing Loads
  12. 12. How? – Mix Design  Mix Designation 1-inch  ¾-inch  ½-inch   Aggregate Crushed Particles Aggregate Size Coarse (2 Fractured Faces) Fine (1 Fractured Face) Type A Type C ≥ 75% ≥ 95% ≥ 70% ≥ 90%
  13. 13. How? Mix Design  Binder Recommend “harder” binder, ie, Grade “bump”  Central Valley – PG 70-10 (rather PG 64-10)   Binder Content 5% air voids or 4% air voids?  Caltrans recommendation  5% for Valley and Desert  4% for Coast and Mountain 
  14. 14. Impact of Aggregate Size on Lift Thickness ½-inch Type C Tolerance TV ± ¾-inch 100 ─ ½-inch 90-98 6 ⅜-inch 64-86 6 No. 4 42-57 7 No. 8 29-39 5 No. 30 13-19 4 No. 200 3-7 2
  15. 15. Nominal Maximum Aggregate Size (NMAS) (one size larger than the first sieve to retain more than 10%) ⅜-inch mix 100 100 90 72 65 48 36 22 15 ¾-inch ½-inch ⅜-inch No. 4 No. 8 No. 30 No. 200 100 99 89 72 65 48 36 22 15 ½-inch mix
  16. 16. What? Type A vs Type C (½-inch Mix) Sieve Size Type A Type C ¾-inch ½-inch 100 95-99 100 90-98 ⅜-inch No. 4 No. 8 No. 30 No. 200 75-95 55-66 38-49 15-27 2-8 64-86 42-57 29-39 13-19 3-7
  17. 17. Construction Considerations  Ratio of Lift Thickness (LT) to NMAS    Maintain LT/NMAS of 4:1 Segregation ** – doesn’t like to be “handled” Compaction – It’s difficult to compact! Need high amplitude, low roller speed to achieve density. ** Pick-up machine MTV Raking
  18. 18. Improper handling and/or placement can cause segregation resulting in raveling.
  19. 19. Paver with Slides inserted over Wings
  20. 20. The WRONG way The RIGHT way
  21. 21. Effective Way to “Pinch” and Roll a Cold Joint
  22. 22. Local Successes    Highway 50 Ramps I-80 at Yolo Causeway Local Agencies Sac County (Watt Ave)  Roseville (Sierra College Blvd)  Elk Grove (Bradshaw Rd)  West Sac (I-80 Off Ramp to West El Camino ) 
  23. 23. Watt Ave & Folsom Blvd   Traffic – Very Heavy w/ High Truck Volume Teichert Mix Design - ½-inch Type C
  24. 24. Watt Ave ½-inch Type C
  25. 25. Watt Ave Number 2 Lane ½-inch Type C Mix After 4 Years < ¼-inch rutting No rutting in any other lanes!
  26. 26. Review - HMA Type C          AKA High Stability, Intersection, Desert Rut Resistant Mix Slow Moving & Standing Loads 3 Choices: 1-inch, ¾-inch, ½ -inch** Coarser Aggregate Gradation & Stiffer Binder OBC at 5% Air Voids** Maintain LT/NMAS of 4:1 High Amplitude, Low Roller Speed Local Success! ** Skip’s Recommendations
  27. 27. QUESTIONS?
  28. 28. Your 1-stop shopping resource www.calapa.net

×