Durable pavement for Steel Decks

1. Durable pavement for Steel Decks

2. History • late 1950s Shell Oil develops jet fuel and hydraulic oil resistant paving for airport taxiways. • 1966 Caltrans uses Epoxy Asphalt on San Mateo- Hayward Bridge (in use). • 1976 Bay Bridge 18mm overlay on lightweight concrete (in use). • 1984 Golden Gate Bridge redecked (in use). • 2000 2nd Nanjing (first Asia project). --5th generation product used for the first time

3. Applications • Orthotropic steel decks • New construction • Replacement paving • Re-decking • Overlays • Temporary chip seals • For replacement deck panels • High (heavy weight) traffic, strategic roads with long life requirement • Fuel and chemical resistant paving Lionsgate Br

4. EA Chemistry • Epoxy cross-linked polymer: continuous phase, asphalt: discontinuous phase • 2 component binder and 2 component bond coat • Part A Resin • Part B Asphalts and cross-linkers • Ambient temperature reactive cure mechanism • Cured polymer is thermoset (won’t melt)

5. Properties • Extremely high fatigue resistance • High strength bond coat • Protects against delamination • Ensures composite action with steel • Resists high summer deck temperatures • Thermoset • Will not melt • Higher modulus than other flexible pavements • Reduces deck deflection Element meshing “Epoxy Asphalt has a fatigue life of 2 to 3 orders of magnitude greater than the PG76-22 I-5 mix…”. --Rutgers University study

6. Properties • Does not oxidize (like all other asphalts) • No embrittlement upon aging • Low voids (typically ~2 %) • Water impermeable • No chloride ion penetration • No corrosion--no membrane required High Temperature bond performance FHWA OECD Long Lived Pavement Study Turner Fairbanks Highway Research Center

7. Fundamental difference • HMA Asphalt, SMA, Gussasphalt, PMA are thermoplastics: will melt • Epoxy Asphalt is thermoset: will not melt “Epoxy Asphalt concrete has shown excellent performance including anti-cracking feature under low temperature, stability under high temperatures and oil-corrosion resistance.…” --W. Wang, Chang’an University

8. Advantages • Low permeability prevents deck corrosion • Fatigue resistance minimizes cracks • 4+ times more stability than standard AC • Handles truck wheel overloads (common in Asia) --Rutgers Univ.

9. Advantages • No rutting or shoving • Use standard AC paving equipment • Very high bond strength • Paving placement is fast • Won’t delaminate “The superior oxidation resistance of the epoxy asphalt material was even more obvious in the Cantabro tests…” --Transit New Zealand—OECD report

10. Typical new construction detail

11. EA Specifications Dense graded mix, ½” (12mm) minus • Basalt rock for skid resistance and long wear • Low temperature paving (110-121ºC) • Time/temp monitoring is critical QC element • Similar temps to warm mix • Lab simulation (fatigue testing) advised for unique decks

12. TENSION Longitudinal stiffener O-T Deck Pavement Stressfrom wheel load deflection

13. Fatigue testingevaluate pavement design on project specific deck • Keys • Realistic paving composite specimens • Good tests take time • Research performance of local materials (aggregates) • Use environmental chamber to control extreme temps

14. Comparison: EA vs. polymer modified AC or SMA

15. Chinese standard deck detail Fatigue test specimen with 3 pt. dynamic load on 300 mm center • 300 mm stiffener spacing • 12 mm deck plate (prior to 1999) • 14 mm deck plate (after 1999) • 50-55 mm EA paving • Locus of highest stress is over stiffeners, particularly in truck lanes • Dynamic fatigue test is good predictor

16. Asian conditions • High deck temps • To 90 °C • Extreme temperature cycle between winter and summer • Construction QC varies widely • Standardized deck design in mainland

17. Asian conditions • Consistent very high truck wheel overloads • To 120 MT on 18 wheelers • SMA and gussasphalt sometimes fail as quickly as 2-3 yrs. SuTong Br.

18. EA: Disadvantages • Time and temperature controls critical • Controls can lead to higher quality and uniformity • Paving plant needs to be within 45-50 minute drive • Too complicated • Over 35 bridges in Asia in past 10 yrs successfully completed • including 1st suspension bridge in Viet Nam • ChemCo provides advisors • Use test section in convenient location to train local paving crews before deck placement • Costs more • Cost difference dwarfed by frequent closures and repaving Thuan Phuoc Bridge DaNang, Viet Nam

19. Fremont, Portland 2011 Repave in July MacDonald, Nova Scotia ~2015 Redeck similar to Lionsgate San Francisco-Oakland Bay ~2012 Single anchored suspension (new East Span) Next in N. America

20. Future • Reduce pavement weight • Local manufacturing • OECD-ECMT Joint Transport Research on long life pavements • (U.S., U.K., France, Germany, Denmark, New Zealand, Australia) • Open graded performance benefits demonstrated • Improve fatigue performance in most challenging applications • Decks with extremely high wheel overloads • Decks with thin plates (12 mm) • Hottest tropical environments

21. Design, test and confirm for wear course success Epoxy Asphalt, a thermoset material, performs on challenging decks Epoxy Asphalt offers life cycle cost benefits Asian lessons learned Over design surfacing when realistic data not available Be flexible to adopt local improvements Conclusions

22. Thanks for your interest!