1. Recovery Method Comparison
Andrew Hanz & Codrin Daranga
Emulsion Task Force
The Center, Heritage Research Group, Indianapolis, IN
June 12, 2019

2. Motivation
Previous results presented by Asphalt Institute showed high variability between labs for many of the tests select.
Evaluate the low temperature evaporation recovery method
Two labs and three machines: Ergon ran on two machines, MTE on one. Three different manufacturers.
Effect of nominal draw down film thickness: 20 mil vs. 30 mil.
Evaluate alternate recovery methods.
LTE (PP-78) vs. Vacuum Recovery (ASTM D7944)

3. Work Plan Factor Description Low Temperature Recovery Method
Evaporation (PP-78)
Vacuum (ASTM D7944)
Film Thickness
20 mils
30 mils
Lab
MTE
Ergon
Emulsions
CRS-2
CRS-2L
CRS-2P
Responses: SPG Continuous Grade, G*/sinδ at grade temp., phase angle at grade temp.

4. Results – CRS-2 Continuous Grade
Low Temperature Evap: Avg: 60.7, Std. Dev = 2.1
Vacuum Recovery: Avg: 60.4, Std. Dev = 0.8

5. Results – CRS-2L Continuous Grade
Low Temperature Evap: Avg: 65.1, Std. Dev = 1.25
Vacuum Recovery: Avg: 64.7, Std. Dev = 1.30
Lab Bias: MTE was higher

6. Results – CRS-2P Continuous Grade
Low Temperature Evap: Avg: 69.8, Std. Dev = 1.7
Vacuum Recovery: Avg: 69.5, Std. Dev = 0.34

7. Results – Effect of Lab

8. Results – Effect of Recovery Method

9. Results – Effect of Film Thickness

10. Observations Effect of Lab Effect of Recovery Method
Bias was shown for one sample CRS-2L. Other samples were equivalent.
Effect of Recovery Method
Same result for both labs across all three emulsions.
Vacuum recovery method was less sensitive to variations in procedure (i.e. film thickness) for CRS-2 and CRS-2P.

11. Next Steps
SPG and EPG from NCHRP 9-50 has established DSR based methods for evaluating emulsion residues.
Apply these concepts to developing precision and bias of recovery methods.
Needs
Ruggedness of individual test procedures.
Single lab and multi-laboratory precision.
Will be critical to NCHRP 9-63 work.