Adhesion and Cohesion of Asphalt in Pavement

2005 Pavement Performance Prediction Symposium

Adhesion and Cohesion of Asphalt in Pavement Cheyenne, Wyoming June 22 – 24, 2005

Laird E. Weishahn, PE Nebraska Department of Roads

STPD-43-2(106) NE Highway #43 Adams to Bennett • • • • • •

Let to Contract = January 13th , 2000 Length of Project = Approximately 15.0 mi. SP-2 Superpave Mixture = 51,400. tons PG 58-28 Binder = 2,700. tons Mill ½” existing & replace with 3½” SP-2 ADT = 2,045 with 9% Trucks

Our SP-2 Superpave Mixture? • SGC # of Gyrations: (0.3 -1 ESALs) – Nini. = 7 – Ndes = 76 – Nmax = 117

Our SP-2 Superpave Mixture? • SGC # of Gyrations: (0.3 -1 ESALs) – Nini. = 7 – Ndes = 76 – Nmax = 117

• Fine Aggregate Angularity = Min. of 40.0

Our SP-2 Superpave Mixture? • SGC # of Gyrations: (0.3 -1 ESALs) – Nini. = 7 – Ndes = 76 – Nmax = 117

• Fine Aggregate Angularity = Min. of 40.0 • VMA = Min. of 14.0%

Our SP-2 Superpave Mixture? • SGC # of Gyrations: (0.3 -1 ESALs) – Nini. = 7 – Ndes = 76 – Nmax = 117

• Fine Aggregate Angularity = Min. of 40.0 • VMA = Min. of 14.0% • VFA = 65% to 78%

Our SP-2 Superpave Mixture? • SGC # of Gyrations: (0.3 -1 ESALs) – Nini. = 7 – Ndes = 76 – Nmax = 117

• • • •

Fine Aggregate Angularity = Min. of 40.0 VMA = Min. of 14.0% VFA = 65% to 78% Dust / Binder Ratio = 0.6 to 1.2

Our SP-2 Superpave Mixture? • SGC # of Gyrations: (0.3 -1 ESALs) – Nini. = 7 – Ndes = 76 – Nmax = 117

• • • • •

Fine Aggregate Angularity = Min. of 40.0 VMA = Min. of 14.0% VFA = 65% to 78% Dust / Binder Ratio = 0.6 to 1.2 PG Binder % = 5.0%

SP-2 Mixture QC Results

SP-2 Mixture QC Results PG Binder % = 5.1%

SP-2 Mixture QC Results PG Binder % = 5.1% FAA = 42.1%

SP-2 Mixture QC Results PG Binder % = 5.1% FAA = 42.1% VMA = 14.4%

SP-2 Mixture QC Results PG Binder % = 5.1% FAA = 42.1% VMA = 14.4% VFA = 75.3%

SP-2 Mixture QC Results PG Binder % = 5.1% FAA = 42.1% VMA = 14.4% VFA = 75.3% Air Voids = 3.6%

PG58-28 Test Results Average of 24 Field Samples

• Original DSR = 1.050 KPa

PG58-28 Test Results Average of 24 Field Samples

• Original DSR = 1.050 KPa • RTFO Dynamic Shear = 2.521 KPa

PG58-28 Test Results Average of 24 Field Samples

• Original DSR = 1.050 KPa • RTFO Dynamic Shear = 2.521 KPa • PAV Dynamic Shear = 4100. KPa

PG58-28 Test Results Average of 24 Field Samples

• • • •

Original DSR = 1.050 KPa RTFO Dynamic Shear = 2.521 KPa PAV Dynamic Shear = 4100. KPa PAV Creep Stiffness = 220. MPa

PG58-28 Test Results Average of 24 Field Samples

• • • • •

Original DSR = 1.050 KPa RTFO Dynamic Shear = 2.521 KPa PAV Dynamic Shear = 4100. KPa PAV Creep Stiffness = 220. MPa PAV m – value = 0.305

PG58-28 Test Results Average of 24 Field Samples

• • • • •

Original DSR = 1.050 KPa RTFO Dynamic Shear = 2.521 KPa PAV Dynamic Shear = 4100. KPa PAV Creep Stiffness = 220. MPa PAV m – value = 0.305

Note: 1 sample failed PAV Specifications

Dates of Construction • May and June of 2000

July Arrives with HOT Temperatures!!

July Arrives with HOT Temperatures!! Calls are coming in to our office asking us to come out and watch the project’s wheel paths turn dark, as the asphalt is flushing to the surface!!

Pictures of Hwy 43

What’s Next?

What’s Next? This project was “tied” to 2 other State Highway Spur overlays. A Change Order/ Supplemental Agreement was approved to require the use of

PG 64-22 binder for the other 2 locations. No flushing occurred on these 2 projects.

What’s Next? We cold milled ½” of the surface off of Hwy 43 and to date the surface has not flushed again. We applied a 1” OGFC on a 3 mile segment for test and evaluation in 2002. It is performing as expected.

The investigation begins….

The investigation begins…. • Samples were provided to Western Research Institute.

The investigation begins…. • Samples were provided to Western Research Institute. – Cores from flushed areas – Cores from non-flushed areas – Original PG Binder samples

Review of Findings • Western Research Institute – Methods Used to Investigate Samples…..

Review of Findings • Western Research Institute – Methods Used to Investigate Samples….. • Extracted binder from top & bottom ¾” of cores using tolune/95% ethanol (85/15)

Review of Findings • Western Research Institute – Methods Used to Investigate Samples….. • Extracted binder from top & bottom ¾” of cores using tolune/95% ethanol (85/15) • Extracted binder with carbon disulfide (CS2) for gas chromatographic simulated distillation

Review of Findings • Western Research Institute – Methods Used to Investigate Samples….. • Extracted binder from top & bottom ¾” of cores using tolune/95% ethanol (85/15) • Extracted binder with carbon disulfide (CS2) for gas chromatographic simulated distillation • Extracted binder subjected to dynamic shear Theological (DSR) analysis

Review of Findings • Western Research Institute – Methods Used to Investigate Samples….. • Extracted binder from top & bottom ¾” of cores using tolune/95% ethanol (85/15) • Extracted binder with carbon disulfide (CS2) for gas chromatographic simulated distillation • Extracted binder subjected to dynamic shear Theological (DSR) analysis • Binder analyzed using size-exclusion Chromatography (SEC)

Review of Findings • Western Research Institute – Methods Used to Investigate Samples….. • Extracted binder from top & bottom ¾” of cores using tolune/95% ethanol (85/15) • Extracted binder with carbon disulfide (CS2) for gas chromatographic simulated distillation • Extracted binder subjected to dynamic shear Theological (DSR) analysis • Binder analyzed using size-exclusion Chromatography (SEC) • Binder analyzed using Automated Heithaus Titration method

Review of Findings • Western Research Institute – Methods Used to Investigate Samples….. • Extracted binder from top & bottom ¾” of cores using tolune/95% ethanol (85/15) • Extracted binder with carbon disulfide (CS2) for gas chromatographic simulated distillation • Extracted binder subjected to dynamic shear Theological (DSR) analysis • Binder analyzed using size-exclusion Chromatography (SEC) • Binder analyzed using Automated Heithaus Titration method • Binder analyzed by Differential Scanning Calorimetry (DSC)

Review of Findings • Western Research Institute – Methods Used to Investigate Samples….. • Extracted binder from top & bottom ¾” of cores using tolune/95% ethanol (85/15) • Extracted binder with carbon disulfide (CS2) for gas chromatographic simulated distillation • Extracted binder subjected to dynamic shear Theological (DSR) analysis • Binder analyzed using size-exclusion Chromatography (SEC) • Binder analyzed using Automated Heithaus Titration method • Binder analyzed by Differential Scanning Calorimetry (DSC) • Binder viewed by Environmental Scanning Electron Microscope

Conclusions

Conclusions • Binder content of “flushed core” was 6.99% in the top and 5.03% in the bottom.

Conclusions • Binder content of “flushed core” was 6.99% in the top and 5.03% in the bottom. • There was “lower boiling” material in extracted core vs. original binder.

Conclusions • Binder content of “flushed core” was 6.99% in the top and 5.03% in the bottom. • There was “lower boiling” material in extracted core vs. original binder. • Binder in top of flushed core is softer than the original binder below 86°F.

Conclusions • Binder content of “flushed core” was 6.99% in the top and 5.03% in the bottom. • There was “lower boiling” material in extracted core vs. original binder. • Binder in top of flushed core is softer than the original binder below 86°F. • More small molecular size material in top of flushed core than in original binder.

Conclusions (Cont.) • The “peptizing” power of the maltenes was very low (<1) implying asphalts are not very compatible (stability problem ?).

Conclusions (Cont.) • The “peptizing” power of the maltenes was very low (<1) implying asphalts are not very compatible (stability problem ?). • Lower molecular weight material is interfering in the crystallization of the wax material present in the original binder.

Conclusions (Cont.) • The “peptizing” power of the maltenes was very low (<1) implying asphalts are not very compatible (stability problem ?). • Lower molecular weight material is interfering in the crystallization of the wax material present in the original binder. • There is an indication of the presence of Carbon Black, possibly crumb rubber?

In Summary “The results do not find any conclusive evidence as to the cause of the asphalt problem on Highway 43 but the analyses show some very unusual chemical properties of the asphalt that most likely contribute to the problem. We (WRI) have become aware of some other states that have experienced similar problems at about the same time.”

Adhesion or Cohesion Problem? Not your usual problem!

Special Thanks

Special Thanks • Michael Harnsberger – Lead Scientist – Western Research Institute

Special Thanks • Michael Harnsberger – Lead Scientist – Western Research Institute

• John Dageforde – Nebraska Department of Roads, Bituminous Laboratory.

Special Thanks • Michael Harnsberger – Lead Scientist – Western Research Institute

• John Dageforde – Nebraska Department of Roads, Bituminous Laboratory • Bob Traudt – Project Manager, Nebraska Department of Roads

Questions?