1. Performance Graded Specifications for Emulsified Asphalt
Moving Forward
Performance Graded Specifications for Emulsified Asphalt
June 20, 2018 – ETF Meeting

2. Topics Status Characteristics of a Provisional Specification Schedule
Development

3. Status EPG-SPG Development Group
Codrin Daranga, Amy Epps-Martin (Edith Arambula), Richard Kim (Cassie Hintz), Gayle King, Andrew Hanz, Guy Sisler, and Mike Voth
Big thanks to the 3 labs that completed testing: Husky, MTE, and Paragon

4. Status “Summer” Testing Program Complete
18 emulsified asphalt samples from across the country.
Samples included: polymer modified (both systems), unmodified, and high floats
Source: ETF

5. Sample Locations – Summer Testing Program

6. Status Asphalt Institute – preliminary analysis complete.
EPG-SPG Working Group
4 teleconferences in 2018
Direction on some issues
Still some data gaps

7. Characteristics of Provisional Standards
Represents best available knowledge.
A tool to stimulate additional research.
A tool to stimulate pilot efforts & data collection.
Not perfect. Changes are often expected.
Limited life (5 to 7 years)
Not widely used

8. Schedule June 2018: Indianapolis Meeting – draft provisional
August 2018: Present at COMP Meeting, TS 2a
Fall 2018: TS 2a ballot ???
Jan / Feb 2019: mid-year TS 2a meeting – address comments
August 2019: COMP Meeting – move to full ballot

9. Provisional Development
Alternatives
Two separate specifications (EPG and SPG)
One specification with complete consensus (data-supported)
One specification with transparency on gaps. Could include options and information appendix.

10. Provisional Development
General Outline
High temperature test (resistance to bleeding)
Low temperature test (resistance to raveling)
Presence of modifier (polymer identifier)

11. Provisional Development
2 or 3 grades?
Industry prefers 2 grade approach
EPG-SPG supports 2 grade approach (unmodified & modified)
Guidance notes for traffic level cut-offs

12. Provisional Development
High Temperature Test
G*/sin δ, Min 0.65 kPa or
Max 3.2 kPa (need thresholds) -Concern the material is too soft for DSR operating range -Consider testing at lower stress levels or lower temperatures

13. Provisional Development
Low Temperature Test
Creep stiffness, T 313: S, Max 500 MPa, at low test 8 sec., °C. On PAV aged material. -Do we consider using a longer time than 8 seconds -Differentiation? -Takes a lot of material, relatively
|G*| at critical phase angle, δc (°C). Derived from testing at 5 °C and 15 °C. -Uses less material -Completing calculations requires good excel template

14. Provisional Development
Presence of Polymer
Phase angle (δ), 84° temperature. where G*/sin δ = 0.65 kPa (unaged sample) -PAV aging allows for normalizing/conditioning of latex in effort to address difference of behavior (not related to performance) -Do we consider other approaches? MSCR % recovery? -Do we consider a sweep test as developed by Shuler? -Do we differentiate by the polymer system used?

15. Thanks!

16. Standards Developed
AASHTO R 78 / ASTM D7497 Low Temperature Residue Recovery
AASHTO PP 81, Intelligent Compaction Technology
AASHTO MP 25/PP 85, PG Hot-Poured Asphalt Crack Sealant
AASHTO MP 33 Materials for Fog Seal