What is Epoxy Asphalt?

epoxy asphalt for steel decks
Laying the levelling course

The two-component Epoxy Asphalt binder, when cured, becomes a two-phase epoxy polymer that contains an asphalt extender. The continuous phase is an acid cured epoxy and the discontinuous phase is a mixture of asphaltic materials. It is a thermoset polymer (it will not melt). This binder, combined with high quality standard asphalt paving aggregates, forms a tough polymer concrete called Epoxy Asphalt Concrete. A hot spray application of an Epoxy Asphalt bond (tack) coat precedes the laying of the Epoxy Asphalt Concrete to provide a very high strength bond to the substrate (concrete, steel or asphalt) that won’t melt.


epoxy asphalt for steel decks

Fatigue Resistance

The excellent fatigue resistance of Epoxy Asphalt enables it to maintain its integrity on orthotropic steel bridge decks without cracking even after the deflections caused by millions of wheel loads. The fatigue resistance is 3-4 orders of magnitude (of fatigue load cycles) higher than polymer modified asphalt binders. The composite action of the epoxy asphalt, unlike that of more flexible pavements, increases the fatigue life of the steel deck and structure by reducing deflection, and thus strain, in the steel.

Corrosion Protection

Epoxy Asphalt provides another layer of corrosion protection for the steel deck in addition to the primary corrosion protection coating because of its low void content of less than 3%. The voids that exist are not interconnected. The result is an impervious (non-porous) pavement with extreme resistance to penetration of water and chloride ions.

Resistance to Rutting and Shoving

Because Epoxy Asphalt binder is a thermoset polymer (as opposed to a thermoplastic polymer such as conventional and rubber-modified asphalt), it provides excellent resistance to rutting and shoving even under high wheel loads in hot and cold climates

Skid Resistance

Epoxy Asphalt pavements include high quality, polish resistant aggregates that provide outstanding skid resistance throughout their life. The Epoxy Asphalt binder does not “bleed” as do thermoplastic bituminous paving materials when the pavement gets hot. As soon as the binder on the aggregate exposed to traffic wears off, vehicle tires see only the aggregate.

Oxidation Resistance

Epoxy Asphalt binders exhibit extremely low rates of oxidation and loss of resiliancy unlike standard and polymer modifed binders. Pavements and overlays constructed with Epoxy Asphalt maintain their properties and do not become more rigid (more brittle) with time. These properties have been validated by several OECD research studies seeking a long-lived pavement for busy roads conducted by the International Transport Forum. In addition, New Zealand is using Epoxy Asphalt as a extended life binder for open-graded porous pavements (with ~20% voids), in an application where the binder is exposed to more air and water by design.

Delamination Resistance

Epoxy Asphalt pavements include a separate, high strength, temperature resistant (non-melting) bond coat. Unlike regular or polymer modified asphalts, the Epoxy Asphalt bond coat provides a high strength bond to the underlying substrate (concrete or steel) even at elevated temperatures of 158°F (70°C). In some cases, where delamination has been identified previously as a primary cause of failure, the Epoxy Asphalt bond coat has been successfully employed with polymer modified SMA pavements on steel decks.

Minimum Traffic Delays

Epoxy Asphalt bond coat is sprayed onto the inorganic zinc-coated deck plates. The bond coat is about 0.03 inches (0.68mm) thick.

Epoxy Asphalt provides the absolute minimum delays for re-paving existing bridges under traffic. An Epoxy Asphalt pavement is ready for traffic in its partially cured state once it has cooled to ambient temperature. The I-day-old uncured Marshall stability of type IX Epoxy Asphalt (measured at 60°C) is generally > 2000 lb (9.4 kN). It develops full strength over two to four weeks depending on average daily temperatures

Local Paving Crews

Local paving crews using conventional asphalt paving equipment install Epoxy Asphalt. ChemCo Systems engineers provide training and technical support during the project. ChemCo supplies the special blending equipment (meter-mix machine) for the two Epoxy Asphalt components. This special equipment is operated by local labor. There is no need to import specialized labor.


Epoxy Asphalt placements on orthotropic steel decks range from the San Mateo-Hayward bridge, paved in 1967, to the SuTong Bridge, which was completed in 2007 and many others [see last table]. The San Mateo-Hayward pavementlasted over 49 years with no maintenance. Orthotropic decks using epoxy asphalt include bridges paved in Canada, Australia, Brazil, China, South Korea, Thailand and Viet Nam. Two bridges have been paved with Epoxy Asphalt and then, after 20 years of successful service, re-paved with the same material. Epoxy Asphalt has been successfully used in climates with winter temperatures below 0°F (-18°C) and summer deck temperatures reaching 170°F (77°C).


2nd Yangtze River Bridge, bridge deck side view

Epoxy Asphalt technology helps meet the challenge of replacing old concrete bridge decks with orthotropic steel decks while minimizing traffic interruption. Shop applied Epoxy Asphalt Chip Seal provides a durable skid resistant surfacing that protects each steel plate from wear and corrosion until all plates are in place and welded together. This technique will be employed on the Macdonald Bridge in Halifax, Nova Scotia during a deck replacement project in the next several years and the bridge will remain open during the project during daytime. Epoxy Asphalt concrete provides the long term wearing surface when it is installed after all deck plates are in place. Both the Golden Gate Bridge and the Lions Gate Bridge used this system for their deck replacement projects. The Macdonald Bridge in Halifax Nova Scotia is undergoing deck replacement currently and also uses Epoxy Asphalt chip seal on the replacement deck sections.

The concrete deck of the heavily traveled Golden Gate Bridge was replaced and paved with no daytime lane closures. Lane shutdown began at 8 PM, paving began at 10 PM and all lanes were opened at 5 AM the next morning. Throughout the night at least one lane was always open in each direction for traffic.

Epoxy Asphalt Concrete vs. Asphalt Concrete


PropertyTest Method (ASTM)Asphalt ConcreteEpoxy Asphalt
Marshall Stability @ 140°F, lb.D15592,5008,000 to 14,000
Marshall Stability @ 400°F, lb.D1559melts4000
Flow value @ 140°F, in. D15590.110.08
Recovery % min. D1559060
Compressive strength @ 77°F, psiD6953400
Comp. modulus of elasticity @ 77°, psiD695167,000
Flex. modulus of rupture @ 77°, psiD293 81640
Flex. modulus of elasticity @ 77°, psi D293380,000
Max. deflection, inchD2930.10.15
Air voids, %D20413 to 5 1 to 2

Epoxy Asphalt Binder & Bond Coat (neat)


PropertyTest Method (ASTM)ValueFailure Location
Tensile Bond Strength to Inorganic Zinc Coated Steel, psiACI 503R300 to 500Bond Coat
Tensile Bond Strength to Portland Cement Concrete, psiACI 503R250 to 350Portland Cement Concrete

Fatigue Resistance

Properly designed Epoxy Asphalt Pavements for orthotropic steel bridge decks provide a durable surface that resists fatigue cracking in the pavement in the negative moment area above the longitudinal stiffeners. Additionally, the pavement, acting as one element in the compsite deck system, reduces deck deflection under load and thus increases the fatigue life of the steel deck plate itself.

Deck Deflection Comparison1


Load, kN
Load, kN1.
Deflection, Bare Steel Plate, mm0. 0.460.570.670.78
Deflection, Epoxy Asphalt/Steel Composite, mm0. 0.510.60

Dynamic testing conducted in independent civil engineering laboratories have shown that Epoxy Asphalt pavements resist fatigue cracking over a wide range of conditions. The following table summarizes recent results.

Fatigue Test Results of Epoxy Asphalt — Steel Deck Composite 1,2


Temperature, °CStatic Deflection, mm Dynamic Deflection, mmCycles to Failure
00.250.0212x106 with no failure
180.350.1812x106 with no failure
600.610.5812x106 with no failure

Above test results from study conducted by Transportation College of Southeast University, Nanjing, China, 2000

1. Test specimen: 14 mm plate 100 mm wide, center point load from underside.
2. Test load: 5kN load @ 10 Hz frequency

Left: Fatigue test setup in dynamic testing machine for 18°C test.
Right: Environmental chamber for fatigue tests at 0 and 60 °C

History of Epoxy Asphalt Pavements: Over 60 Bridges and 400 km of bridge lanes paved


Name of bridgeLocationDateDeck TypeArea sq.feetArea sq.meterApprox.Tons
San Mateo-HaywardSan Mateo, CA19679/16" O-T Steel430,000 39,948 5,495
San Diego-Coronado San Diego, CA19693/8" O-T Steel116,000 10,777 1,482
San Francisco- Oakland Bay Bridge San Francisco, CA 1969 PC Concrete155,000 14,400 1,981
McKay Halifax, N. S. 19703/8" O-T Steel128,000 11,892 1,636
Queensway ALong Beach, CA1970O-T Steel96,000 8,919 1,227
MacDonald Halifax, N. S. 1971Conc. Filled StI. Grid Main Span119,00011,0551,521
Ross IslandPortland, OR1972 PC Concrete146,000 13,564 1,866
Evergreen PointSeattle, WA1972PC Concrete270,000 25,084 3,450
Sellwood Portland, OR 1973 PC Concrete47,000 4,366 601
Fremont Portland, OR 19735/8" O-T Steel155,000 14,400 1,981
Costa de Silva (Rio-Niteroi) Rio de Janeiro, Brazil 1973 3/8" O-T Steel220,000 20,439 2,811
1-94 BridgesMinneapolis, MN 1973 PC Concrete99,0009,197 1,265
Mercer Montreal, Quebec1974 3/8" O-T Steel21,000 1,951 268
Lions Gate Vancouver, B. C. 197515/32" O-T Steel77,000 7,154 984
San Francisco-Oakland Bay BridgeSan Francisco, CA (2 decks)1976 PC Concrete1,475,000137,032 137,032
1977 1,290,000 119,845 16,485
Luling New Orleans, LA 1983 7/16" O-T Steel219,000219,0002,799
Ben Franklin Philadelphia, PA19865/8" O-T Steel 632,000 58,7158,076
Golden GateSan Francisco, CA 19865/8" O-T Steel 576,000 53,5127,361
McKayHalifax, N. S. 19903/8" O-T Steel 128,00011,8921,636
San Diego-CoronadoSan Diego, CA 19933/8" O-T Steel 1,65015321
ChamplainMontreal, Quebec19933/8" O-T Steel 200,000 18,581 2,556
Maritime Off-Ramp Oakland, CA 19965/8" O-T Steel 69,0756,417883
2nd Yangtze Bridge Nanjing, China 200014 mm(approx. 9/16") O-T Steel 548,52750,9607,014
Lions Gate Bridge Vancouver, B.C. 2002O-T Steel 77,0007,154700
Taoyaomen Zhoushan, China 200314 mm O-T Steel 278,173 25,8433,557
Runyang Cable-stay Zhenjiang, China 200414 mm O-T Steel 308,34828,6463,943
Runyang Suspension Zhenjiang, China 200414 mm O-T Steel 572,64653,201 7,323
DaguTianjin, China 2004O-T Steel 66,640 6,191833
3rd Yangtze Bridge Nanjing, China 2005O-T Steel 525,066 48,780 6,714
PingshengNanjing, China 200614 mm O-T Steel 525,06648,7806,714
Zhanjiang BayZhanjiang, China 2006O-T Steel 169,47415,745 2,167
FenghuaTianjin, China 2006O-T Steel 13,1321,220168
NanhuanBeijing, China 2006O-T Steel 115,626 10,742 1,479
SutongNantong, China 2007O-T Steel 764,00070,97810,943
Hangzhou Bay (2 bridges) Ningbo, China 2007O-T Steel 737,32768,5009,429
YangluoWuhan, China 2007O-T Steel 521,71548,4696,671
Houhai Shenzhen, China 2007O-T Steel 44,9104,172574
Fu Ming, Chin Feng, Li Gong, Si Hai Tianjin China 2007O-T Steel 138,43912,8611,770
Huang Pu (2 bridges) Guangzhou China 2008O-T Steel 556,830 51,731 8,700
Xihoumen and Jintang Zhoushan China 2008O-T Steel 800,868 74,40310,110
3rd Yellow River Jintan China 2008O-T Steel 333,976 31,0274,271
YuZuiChongqing China 2009O-T Steel 200,800 18,6553,100
BaLingGuizhou China 2009O-T Steel 261,88824,3304,043
BaishazhouWuhan China 2009O-T Steel 378,88835,2008,786
XiangluowanTianjin China 2009O-T Steel 31,609 2,937 486
Thuon Phuoc DaNang Viet Nam 2009O-T Steel 84,368 7,8381,079
BanpaldBangkok Thailand 2009O-T Steel 40,9223,802523
Pong Pech Bangkok Thailand 2009O-T Steel 40,9223,802 523
Rama IV Bangkok Thailand 2009concrete54,5625,069698
E'dong Bridge Hu Bei, China 2010 O-T Steel 258,287 23,996 3,311
Jing yue Bridge Hu Bei, China 2010 O-T Steel 403,544 37,491 6,243
Qing dao Bay Bridge Qing Dao, China 2010 O-T Steel 517,160 48,046 8,000
Chong Qi Bridge Jiang Su, China 2011 O-T Steel 265,296 265,296 4,100
South Train Station Bridge Nan Jing, China 2012O-T Steel 275,55125,600 4,257
Fremont Bridge Portland, OR 20125/8" O-T Steel 176,287 16,378 2,253
Jiu jiang Second Bridge Jiang Xi, China 2013 O-T Steel 358,457 33,302 5,543
Huang yi Bridge Si Chuan, China 2013 O-T Steel 100,097 9,299 1,543
Tao hua yu Bridge Zheng Zhou, China 2013 O-T Steel 237,604 22,074 3,671
San Francisco-Oakland Bay Bridge San Francisco, CA 2013 O-T Steel 358,953 33,348 3,900