1. Epoxy Asphalt vs alternatives
(SMA and gussasphalt)
For ORTHOTROPIC STEEL BRIDGE DECK PAVEMENTS

2. History—Orthotropic decks

EUROPE 1950

NORTH AMERICA 1964

ASIA 1979

3. Problems on Steel Decks



RUT/SHOVE
CRACK
DELAMINATION



Most Frequent = Cracks Over
Longitudinal Stiffeners
Cracks Lead to Disbonding
Most Severe in Hot Weather

4. Rutting and Shoving

5. Fatigue Cracks

6. Longitudinal stiffeners (ribs)

7. Wheel load deflection
TENSION
STIFFENER

8. Epoxy Asphalt (EA) since 2000
40+ bridges selected EA, most in Asia
 Over 800,000 m² of Deck
 Longest span suspension bridge in China
 First suspension bridge in Viet Nam


9. Long lived EA pavements
San Mateo, 46
Golden Gate, 27
Fremont, 39
SF Bay, 37

10. What is Epoxy Asphalt?

Two‐Component Polymer system
 1st Component (Part A) = Epoxy Resin
 2nd Component (Part B) = Hardener & Asphalt

With Aggregate = Epoxy Asphalt Concrete
“In 19 years, after approximately 1.5 billion vehicles,…the 19 mm epoxy
asphalt surfacing (on the SF Bay Bridge) has good skid resistance and is still
performing well.”
--C. Seim, ACI SP, 1995

11. Cured Epoxy Asphalt

A stable and durable “2‐Phase”
Polymer System

Hardener/Epoxy = Continuous Phase

Asphalts = Discontinuous Phase

Hardener/Epoxy Predominates

12. What is a mastic?







Mastics (also called gussasphalts) are over‐filled mixes
with small aggregates dispersed within binder
No Aggregate Skeleton formed
Requires stiffer binders than concretes
Tension and compression stresses carried by stiff binder
Poured in place under high temperature (240‐260C), no
compaction
Use special heated transport vessels with internal mixing
Require friction chips spread over surface and rolled in
(very low skid numbers without)

13. Fundamental Difference

Asphalt, SMA, mastic asphalts
(gussasphalt) are “Thermoplastics.”
Will Melt !

Epoxy Asphalt is “Thermoset.”
Will Not Melt !

14. Property Comparison
Epoxy Asphalt has:




Higher Strength/Stability
Better Stiffness over Temperature Range
Better Resistance to Creep/Flow
Better Adhesion
‐versus thermoplastic asphalts

15. Higher Strength/Stability

Greater than Four Times Stability of Mastic

Withstands Higher Overloads without Damage

Does Not Rut or Shove
“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

16. Flexural strength/stiffness at 15°C
Flexural
Strength
MPa
Flexural
Modulus
MPa
Mastic (guss) Asphalt
5.95
563
SMA
4.73
355
Epoxy Asphalt
16.4
2574
HUANG Wei, QIAN Zhendong, CHEN Gang & YANG Jun
Chinese Science Bulletin 2003 Vol. 48 No. 21 23912394

17. Rutting test, 70°C
Transition Layer
25 mm Epoxy Asphalt
Surface Layer
25 mm Epoxy Asphalt
Depth – mm
0.32
20‐25 mm mastic asphalt 35‐40 mm Epoxy Asphalt
0.34
25 mm Epoxy Asphalt
30‐40 mm SMA
0.74
30 mm SMA
35 mm SMA
1.05
20‐30 mm mastic asphalt 35‐40 mm SMA
1.74
30 mm mastic asphalt
3.58
40 mm mastic asphalt
Li Xuelian, Zhou Zhigang, Key Laboratory of Highway Engineering, Changsha University of Science & Technology

18. Stiffness Benefits
Less Softening as Temperature Increases
Reduces Deflection of Deck
 Increases Fatigue Life of Steel Deck System

--Tom Bennert, report for
NYNJPA Rutgers Univ.,
2007

19. Better Resistance To Creep/Flow
 Much More Elastomeric
 Better Fatigue Life
 No Permanent Deformation under High
Loads
 Reduced Damage by Slow Moving or Stopped
Overloaded Trucks
“The superior oxidation resistance of the epoxy asphalt
material was even more obvious in the Cantabro
tests…”
--Phil Harrington, Transit New Zealand—OECD report

20. Fatigue tests
At Service Temperature Extremes
At Expected Overloads

21. Fatigue testing: composite beam, constant load

Type V– Standard Epoxy Asphalt

14 mm Plate with 300 mm Wide Stiffeners on 600 mm Centers

Conducted at 0, 18, 60 deg C

10 Hz Frequency

Normal Load & Overload

NO FAILURE @25 Million Cycles
Fatigue test specimen
with 3 pt. dynamic load
on 300 mm center

22. Type IX – New Generation Epoxy Asphalt

12 mm Plate with 300 mm Wide Stiffeners on 600 mm Centers
 Conducted at 21 deg C
 10 Hz Frequency
 Normal Load & Overload

NO FAILURE @ >25 Million Cycles

Potential savings in deckplate mass, dead load and
suspension steel
“If all aspects of the process are correctly handled, Epoxy Asphalt should be able to
provide a surfacing material that can be expected to meet the aim for a much
extended practically maintenance free service life, i.e., 30 years or more.”
--Int’l Transport Forum—2008 OECD report

23. Fatigue comparison ‐ Constant Strain

24. Pavement Adhesion
ChemCo Bond Coat Type 1f
 Pull‐Off Adhesion 2.4 MPa @ 70º C
 Negligible slippage at bond line assures
composite action
 No Delamination

High Temperature bond performance
FHWA OECD Long Lived Pavement Study
Turner Fairbanks Highway Research Center

25. Typical construction detail

26. Automated bond coat spray
Img_0381.jpg

27. Meter mix machine
PROPORTIONS THE TWO
BINDER COMPONENTS
MIXES THE COMPONENTS
INJECTS AMOUNT FOR EACH
BATCH

28. Batch temperature

29. Temperature controls

First compaction step
must be completed
before 82℃

Finish before 65 ℃

30. Keys to Success
 Proper Pavement Design
 Composite of Deck & Pavement
 Fatigue Test of System
 Strict Quality Control
 Batch Temperature Control
 Immediate Compaction to <3%
Voids

31. Cost/Benefit
Comparison to Mastic Asphalt/SMA
 Overall weight savings with potential lighter
pavement structure
 As much as 10% of box structure weight
 Lower deckplate thickness possible
 Fast Installation: 3,000 sq. m. per day
 Saves waterproofing step
“…epoxy asphalt mixture is much more resistant to low temperature thermal
cracking (-30°C) than conventional asphalt concrete mixtures.”
--Mihai Marasteanu, FHWA research report, University of Minnesota, 2008.

32. Lifecycle analysis
EPOXY ASPHALT LIFE = 20 YEARS
SMA or Mastic ASPHALT LIFE = 5‐8 YEARS
SMA or GUSSASPHALT COST = X
Assume: EPOXY ASPHALT COST = 2X
20 YEAR COST
EPOXY ASPHALT = 2X
SMA/GUSSASPHALT = 4X

33. EA compared to mastic
 Longer Fatigue Life of Steel Deck Composite Action

Avoids Traffic Problems of Replacement
 Does Not Oxidize / Retains Flexibility
 Resists Automotive Fuels and Fluids
 Provides Impermeable Water Barrier

34. Summary
•EPOXY ASPHALT IS UNIQUE
•LONG SUCCESSFUL HISTORY
•EXCELLENT RESULTS IN ASIA and N America
•OFFSETS TO HIGHER MATERIAL COST
1. LONG LIFE
2. LOW WEIGHT
3. FAST INSTALLATION

35. Thanks for your interest!