At the California Asphalt Pavement Association (CalAPA) Spring “Technical Tune-Up” Educational Workshop held April 5, 2022 in Brea, a presentation titled, "Warm Mix Asphalt Focus, by Cameron Richardson, Technical Marketing Manager, Ingevity. An experienced expert will provide best practices on the use of WMA to maximize the benefits of this technology. He will cover all aspects from mix design, through production and finishing with compaction.

1. CalAPA - Asphalt Tech Tune-Up
Educational Conference
April 5th, 2022
Cameron Richardson
Technical Marketing Manager
Warm Mix Asphalt (WMA)
“From Lab to Slab”

2. 2
1.Current Status WMA in CA
2.WMA in Action
▪ Lab Design
▪ Production
▪ Construction
3.The Road Forward
Agenda

3. 3
NAPA Survey on WMA Usage
Data taken from NAPA’s “Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2019”
WMA Technology
% Production
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
Production Plant Foaming 83.0 92.0 95.4 88.3 87.0 84.5 72.0 76.9 64.7 63.2 51.0
Additive Foaming 2.0 1.0 0.2 2.0 0.3 0.0 2.1 0.0 0.0 0.7 0.0
Chemical Additive 15.0 6.0 4.1 9.4 12.1 15.0 25.2 21.1 32.2 34.3 48.3
Organic Additive 0.3 1.0 0.3 0.2 0.0 0.5 0.7 1.9 3.1 1.8 0.7
0
20
40
60
80
100
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
WMA
Technology
Usage
(%) Percentage of WMA Production Placed by Technology
Type
Production Plant Foaming Chemical Additive Organic Additive

4. 4
Production Temperature Options
250º
200º 350º
300º
HMA
True Warm Mix Hot WMA
275º
225º 325º

5. 5
Current Status of WMA
▪ California
▪ Currently elective spec at CA State level
▪ Engineer/Agency option at local level,
Greenbook
▪ District 4 mandates on all projects
▪ United States
▪ Some states are moving the needle
▪ Bonus/Incentive specs
▪ Mandates

6. 6
WMA Lab Design
▪ How to dose
▪ Typical dosage range
▪ Standard mixing process
▪ Mixing and Compaction Temps
▪ AASHTO R30 update for WMA –
▪ Chemistry selection
▪ Binder compatibility
▪ Aggregate type compatibility

7. 7
WMA Production
▪ Plant Basic Needs:
▪ Injection pump system with mass flow meter
per State specifications
▪ External metering per manufacturer
recommendations for hardware and plant
software
▪ Production Tips:
▪ Fire-up plant at hot mix temps then reduce till
desired temp met
▪ Most plants are set up for HMA temps only
▪ Flights and burner need to be tuned properly
▪ Maintain & monitor baghouse temperature;
approx. 200°F
▪ Mix will have a heavier viscosity and will act
“heavier” in pugmill and transfer points

8. 8
WMA Construction BEST PAVING PRACTICES ARE STILL BEST PAVING
PRACTICES!
• Situational dosing discussion
• Compaction aid (HMA)
• “True” warm mix
• Long haul (HMA → WMA)
• Cold Season (HMA)
• RHMA
• Verify rolling pattern – density curve
• Rubberized HMA/WMA
• Seal mat – allow swell – finish rolling
• Pay attention to material reaction
• Standard Compaction Windows …

9. 10 min – HMA Compaction Window
18 min – WMA Compaction Window
80% Increase!!
Field Compaction Window
Assumptions
▪ 2 in lift
▪ 50°F Ambient Temps
▪ 5 mph wind speed
▪ Dense graded mix
HMA
Mix Temp - 305°F
Compaction Temp
Window 290°F - 220°F
WMA
Mix Temp - 275°F
Compaction Temp
Window 260°F - 190°F

10. 62°F Difference
HMA thermal imaging

11. 24°F Difference
WMA thermal imaging

12. 12
Next Steps…
▪ NAPA’s the road forward
▪ NCHRP 843
▪ GHG & Energy reduction
▪ Balanced Mix Design - WMA
▪ Continued temp drop
▪ *Dispersed Asphalt Technologies ≈ 225°F

13. 13
THANK YOU &
ENJOY LUNCH
Cameron Richardson
SW Technical Marketing Manager
Cameron.richardson@ingevity.com
279.400.9255