China Vice Construction Minister Dr. Huang
Wei and Bob Gaul discuss future bridge deck projects.
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ChemCo Systems Epoxy Asphalt was recently installed
on several steel deck bridges in China inlcluding the Chongqi
Br. in Qidong in 2011. After 38 years of service, the Epoxy Asphalt
on the Fremont Bridge in Portland was replaced (see link above).
For 2010, Jiaozhou (Qingdao) Bay Bridge (2 separate
cable stay spans), Eastern Hubei (E-Dong) Yangtze River Bridge
and Jingyue Yangtze River Bridge Between Hubei and Hunan).
2009 projects included China, Thailand and Viet
Nam locations.
China bridges were the YuZui Bridge in Chongqing,
the BaLinghe Bridge in Guizhou, the Baishazhou Bridge in Wuhan
and the XiangLuoWan Bridge in Tianjin.
In DaNang, Viet Nam, the Thuan Phuoc Bridge over
the Han River, was completed midyear. This is Viet Nam's first
long span steel decked suspension bridge.
In Bangkok, Thailand, several short span bridges
were paved including Rama IV, Pong Pech and Banpald.
2008 projects included:
Huangpu Bridges (cable-stay and suspension) in
Guangzhou, Xihoumen and Jintang Bridges in Zhoushan and the 3rd
Yellow River Bridge in Jintan. The Xihoumen Bridge is now the
world's second longest span suspension bridge.
2007 projects included:
Sutong Bridge, Hangzhou Bay Bridge, Yangluo Bridge,
and Houhai Bridge. Sutong Bridge is the world's longest span for
a cable-stay design. Other new bridges in Tianjin include the
FuMin, ChiFeng, Li GongGluo and SiHai Bridges.
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Epoxy Asphalt Concrete is a polymer
concrete with a 46 year history as an extremely durable bridge deck
surfacing. Since 1967 over 450 million pounds (225,000 tons) have been
installed on bridge decks totaling over 120 million square feet. Installations
have exhibited excellent performance,  including
the San Francisco-Oakland Bay Bridge where 30,000 vehicles travel each
lane per day and the 3/4 inch (19 mm) overlay surface has withstood
more than 36 years of extremely heavy use (over 360 million vehicles
since installed).
Epoxy Asphalt is specified by Caltrans
for the orthotropic steel deck of the new $6.4 billion East Span of
the San Francisco Bay Bridge (opens in fall 2013). This ultra high performance
pavement is also in a phase 3 evaluation by the International Transport
Forum of OECD in a multi-country
research program seeking long life pavements for strategic roads.
Features
Epoxy Asphalt's most common applications are: 1)
as a thin overlay (3/4 to 2 inch thickness) lightweight wear course
for repair, replacement or new construction and 2) as a paving surface
for orthotropic steel decks* where toughness and elastic composite behavior
are critical. Several bridges have used Epoxy Asphalt chipseals as wear
surfaces during bridge deck replacements. A newer use of Epoxy Asphalt
is as an extremely durable binder for open
graded pavements. Other benefits include:
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Low porosity prevents deck
corrosion |
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Superior substrate adhesion
(pavement stays bonded at high ambient temperatures) |
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Extreme durability and flexibility |
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Can be installed as thin overlay
(3/4") if added weight is critical |
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Roadway open after 2-4 hours
(light traffic) |
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3-4 times stronger than conventional
asphalt concrete |
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Won't rut or shove, even with
heavily overloaded trucks |
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Won't oxidize and harden upon
aging like regular asphalt |
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Lightweight aggregate OK if
very low pavement weight is needed |
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Negligible cure shrinkage |
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Bond coat and binder will not melt |
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Applied with conventional
asphalt paving equipment |
What is Epoxy Asphalt?
Epoxy Asphalt Concrete is a polymer concrete that
is composed of a slow curing, Epoxy Asphalt binder mixed together with
standard asphalt concrete aggregates in the pug mill of an asphalt plant.
The Epoxy Asphalt binder is a two-phase chemical system in which the
continuous phase is a thermoset epoxy and the discontinuous phase is
a mixture of specialized asphalts. A hot spray application of an Epoxy
Asphalt bond (tack) coat precedes the laying of the Epoxy Asphalt Concrete.
Epoxy Asphalt concrete is applied and compacted with conventional asphalt
concrete paving equipment. The pavement is quickly ready for traffic
in its partially cured state once it has cooled to ambient temperature.
It develops full strength over two to four weeks depending on ambient
temperatures.
Shell Oil Company developed the first generation
of Epoxy Asphalt in the late 1950's as a jet fuel and jet blast resistant
specialty pavement for airfield applications. In 1967, Epoxy Asphalt
was selected for its first commercial application on a bridge deck as
the wear surface of the mile long orthotropic steel deck span of the
San Mateo-Hayward Bridge across San Francisco Bay. This deck is still
in excellent condition after 46 years. Today, ChemCo Systems provides
experienced manfacturing, R&D and technical service and continues
to improve the performance with new generations of Epoxy Asphalt, particularly
for flexible decks, extreme climates and very heavily loaded trucks.
Epoxy Asphalt may also be referred to as Epoxy Bitumen or Bitumen Modifed
Epoxy in countries outside of North America.
Physical Properties
The two-phase Epoxy Asphalt binder is a thermoset
polymer, that is, it will not melt after it has cured. This is a significant
advantage of epoxy asphalt because conventional asphalts are thermoplastic
polymers that readily melt at elevated temperatures (which can lead
to delamination failures). Fresh laid Epoxy Asphalt pavement is not
subject to rutting or shoving because the polymeric curing process is
advanced during batching to a state of high stability. Thus, the dense-graded
mix can be designed with a low void content without the danger of bleeding
or flushing. The result is an extremely waterproof pavement that can
be opened quickly.
Substrates
Epoxy Asphalt has excellent adhesion with the following substrates:
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Portland Cement Concrete |
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Lightweight concrete |
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Steel (zinc-primed and unprimed) |
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Asphaltic Concrete and chip seals |
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Tar-Rubber Concrete |
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Epoxy Asphalt |
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Epoxy overlays |
*Orthotropic steel deck sections are also called orthotropic box girders.
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