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

Topics Status Characteristics of a Provisional Specification Schedule Development

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

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

Sample Locations – Summer Testing Program

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

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

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

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.

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

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

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

Provisional Development Low Temperature Test Creep stiffness, T 313: S, Max 500 MPa, at low test temp. @ 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

Provisional Development Presence of Polymer Phase angle (δ), 84° Max, @ 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?

Thanks!

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