Epoxy Asphalt Bridge Deck Pavement

Epoxy Asphalt Concrete is a polymer concrete with a 50 year history as an extremely durable bridge deck pavement. 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 280,000 vehicles travel each day. The 3/4 inch (19 mm) overlay surface withstood more than 39 years of extremely heavy use (over 3 billon vehicles) before the East Span of the bridge was replaced.

Recently, Epoxy Asphalt was placed on the orthotropic steel deck of the new $6.4 billion East Span of the San Francisco Bay Bridge (opened Sept 2013, pictures below). Caltrans produced a Youtube video on this project. This ultra high performance pavement is also in a multi-phase evaluation by the International Transport Forum of OECD in a multi-country research program seeking long life pavements for strategic roads.

EPOXY ASPHALT

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NEW SAN FRANCISCO BAY BRIDGE

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Fremont Bridge Resurfacing

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Epoxy Asphalt 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 chip seals as temporary wear surfaces during bridge deck replacements such as the new deck segments currently being installed on the Macdonald Bridge in Halifax, Nova Scotia. A newer use of Epoxy Asphalt is as an extremely durable binder for open graded permeable pavements. Following is the link for a new video for the open graded use in NZ: NZ video. Other benefits include:

  • Low porosity prevents deck corrosion
  • Superior substrate adhesion (pavement stays bonded at high ambient temperatures)
  • Extreme durability and flexibility
  • Can be installed as thin overlay (3/4″) if added weight is critical
  • Roadway open after 2-4 hours (light traffic)
  • 3-4 times stronger than conventional asphalt concrete
  • Non-melting; won’t rut or shove, even with heavily overloaded trucks
  • Won’t oxidize and harden upon aging like regular asphalt
  • Lightweight aggregate OK if very low pavement weight is needed
  • Negligible cure shrinkage
  • Bond coat and binder will not melt and are extremely chemical resistant
  • 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 bridge deck application as the wear surface of the mile long orthotropic steel deck span of the San Mateo-Hayward Bridge across San Francisco Bay where it lasted 47 years. Today, ChemCo Systems provides experienced manfacturing, R&D and technical service and continues to improve the performance with new generations of Epoxy Asphalt including our ultra high performance Type 9 Composite 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:

  • Portland Cement Concrete
  • Lightweight concrete
  • Steel (zinc-primed and unprimed)
  • Asphaltic Concrete and chip seals
  • Tar-Rubber Concrete
  • Epoxy Asphalt
  • Epoxy overlays