Warm Mix Asphalt Use in Sioux Falls. Galynn Huber, Street/Fleet Manager and Wes Philips, Principal Engineer

Transcription

1 Warm Mix Asphalt Use in Sioux Falls Galynn Huber, Street/Fleet Manager and Wes Philips, Principal Engineer 1

2 Introduction WMA represents a group of technologies which allow a reduction in the temperatures at which asphalt mixes are produced and placed. Temperature Range of Asphalt Mixes Hot Mix Asphalt F Warm Mix Asphalt F Sometimes defined as having a maximum temperature of 275 F WMA is produced with special additives or technologies at temperatures 30 to 70 F lower than typical HMA 2

3 What makes WMA work? The basic function of WMA technology is to change the binder properties at lower temperatures to allow for sufficient coating of the aggregates, while maintaining good workability and durability. Asphalt Binder Specifications PG

4 Benefits of WMA Improved working conditions Less fumes and emissions Less energy consumption Decreased binder aging during production Early site opening Cool weather paving Compaction aid for stiff mixes Longer haul distances Improved and more consistent compaction Early Concerns Cost Equipment Adjustments Performance Moisture Susceptibility Rutting 4

5 Plant Concerns with WMA Lower production temperatures could lead to: Less efficient burner operation Incomplete drying of the virgin aggregates Condensation in the baghouse Increase amperage on motors WMA in the US European scan/study tours (2002 and 2007) Growth has been rapid Technologies: 3 (2005) 23 (2010) Trials: 15 states (2007) - 45 states (2010) Market: 2% (2007) 10% (2010) 50% (2015?) Key properties being evaluated Deformation resistance/rutting Cracking/fatigue Moisture sensitivity 5

6 WMA Technologies WMA Technologies 6

7 WMA Technologies Most common technologies Foam Evotherm (Chemical) Sasobit (Wax) Warm Mix Asphalt by State,

8 Summary of WMA Use in US Approximately 500 million tons of asphalt produced annually First test section placed in million tons of WMA in million tons of WMA in /3 of all asphalt produced (160 million tons) in 2014 was WMA FHWA goal to have WMA make up ½ of all asphalt quantities in the next few years Lower Fumes/Emissions 8

9 Lower Fumes/Emissions HMA Temp = 320 of WMA Temp = 270 of Lower Fumes/Emissions Hot Mix Asphalt Warm Mix Asphalt 9

10 Lower Fumes/Emissions Warm Mix Asphalt Hot Mix Asphalt Lower Fumes/Emissions Hot Mix Asphalt Warm Mix Asphalt 10

11 Improved Compaction Improves workability and ease of compaction Compaction is important to long term performance of mixture Allows placement and compaction during cooler weather Better Performance? Warm Mix Asphalt oxidizes at a slower rate Improved elastic resistance to thermal cracking and improved aggregate coating. 11

12 Which lane is WMA? Which lane is WMA? Decreased binder aging, light oils never reach boiling point (285 F) Pavement stays blacker, longer 12

13 Energy Savings with WMA Fuel savings with WMA in Europe have been reported to be from 20% to over 50% for some WMA technologies. US studies have reported burner fuel savings of 0-30% with 15-25% being typical. Source: National Center for Asphalt Technology (NCAT) at Auburn University Production Temperature and Fuel BTU/Ton 13

14 WMA Production Temperatures Warm Mix Asphalt: Best Practices Quality Improvement Series (QIP) 125 Stockpile Moisture Management Burner Adjustments and Efficiency Aggregate Drying and Baghouse Temperatures Drum Slope and Flighting Combustion Air RAP usage Placement Changes 14

15 Combining WMA and RAP WMA technologies can improve the ability to properly coat aggregates and RAP during production Lower production temperatures will reduce plant aging of binders which may allow for increased use of RAP without grade bumping Many agencies allow higher RAP with WMA Cost of WMA Foaming Systems $100,000-$200,000 up front Water to operate is inexpensive If liquid antistrip is needed, adds $1-2/ton Used by a majority of WMA producers Additive Systems $2-$4/ton Figures above do not include any fuel savings 15

16 Cost of WMA Hot Mix Asphalt Warm Mix Asphalt 2014 $46.75 (CM) $49.32 (M&R) 2015 $43.10 (M&R) $44.60 (CM) 2016 $45.60 (CM) $46.40 (M&R) City of Sioux Falls Material Purchase Contracts (cost includes asphalt purchase only, not laydown.) City of Sioux Falls WMA Quantities Year Tons , ,000 16

17 City of Sioux Falls Experience Compaction Workability Crew Acceptance Emissions/Odor Implementation Performance Color Cracking Kiwanis Avenue Overlay Kiwanis Avenue from 41 st Street to 49 th Street Traffic Volume of 10,100 AADT 2-inch Mill & Overlay in 2014 Side-by-side comparison of Hot Mix and Warm Mix Asphalt Warm Mix Asphalt $49.32/ton from Myrl & Roy s Hot Mix Asphalt $46.75/ton from Concrete Materials Approximately 1600 tons total 17

18 Kiwanis Avenue Overlay Warm Mix Asphalt Hot Mix Asphalt Kiwanis Avenue Overlay Hot Mix Asphalt Warm Mix Asphalt 18

19 Kiwanis Avenue Overlay Warm Mix Asphalt Hot Mix Asphalt Kiwanis Avenue Overlay Warm Mix Asphalt Hot Mix Asphalt Comparison of transverse crack that has reflected through overlay 19

20 Kiwanis Avenue Overlay Comparison of transverse crack that has reflected through overlay Hot Mix Asphalt Kiwanis Avenue Overlay Comparison of transverse crack that has reflected through overlay Warm Mix Asphalt 20

21 Kiwanis Avenue Overlay Warm Mix Asphalt Hot Mix Asphalt Comparison of transverse crack that has reflected through overlay Kiwanis Avenue Overlay Paving Joint Warm Mix Asphalt Hot Mix Asphalt Comparison of transverse crack that has reflected through overlay 21

22 Questions? Wes Philips Galynn Huber