Epoxy Asphalt Concrete is a polymer concrete with a 53 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 original 3/4 inch (19 mm) EA overlay (over lightweight concrete) withstood more than 39 years of extremely heavy use (over 3 billon vehicles) before the East Span of the bridge was replaced and later dismantled due to seismic concerns.
Epoxy Asphalt was placed on the orthotropic steel deck (also referred to as steel box girder decks) 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.
More recently, Epoxy Asphalt and Epoxy Asphalt chipseal were used on the Macdonald Bridge in Halifax, Canada in a project called “The Big Lift” where 46 deck sections were replaced with newly fabricated deck sections with project work at night and on weekends while the bridge was kept in service during weekday commute periods. This project was designed so there was minimal disturbance of workweek traffic over the 2 years of deck panel replacement.
Epoxy Asphalt (EA) binder was extensively researched and field tested in a multi-phase evaluation by the International Transport Forum of OECD in a multi-country evaluation seeking long life pavements for strategic roads. This recent application of the highly oxidation resistant EA binder has focused on open graded, permeable surface pavements (>20% air voids), (also called OGFC pavements) for use in on-grade roadway installations with the goal of significant life-cycle extension. OGFC pavements offer significant safety advantages along with 6-10 decibel tire noise reduction versus dense graded flexible pavements or concrete. Permeable pavements also offer other significant safety and environmental benefits. Full scale test programs and projects are active in several countries including the U.S., the U.K., New Zealand and the Netherlands.
Recently, the latest generation of Epoxy Asphalt, Type IX (9), was used to replace failed pavement on
the Tianxingzhou Bridge in Wuhan, China, a cable-stay design. The bridge has two side-by-side independent decks so one side was closed for restoration while the other side was converted to 2-way traffic. The new EA pavement tested in excess of 100 kN for Marshall stability (test results from production batches) which is the highest value for flexible asphaltic pavements. A new 4 minute video shows the whole project from pavement removal to completed project.
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 in-service bridge deck replacements such as the new deck segments recently installed on the Macdonald Bridge in Halifax, Nova Scotia.
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)
3-6 times stronger than conventional asphalt concrete
Non-melting binder; pavement won’t rut or shove, even with heavily overloaded trucks
Binder won’t oxidize and harden upon aging like regular asphalt
Lightweight aggregate OK in mix design if very low pavement weight is needed
Negligible cure shrinkage
Bond (tack) coat and binder will not melt and are extremely chemical resistant
Installed with conventional asphalt paving equipment
*also called steel box girder decks
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 flexible, thermoset (non-melting) epoxy polymer and the discontinuous phase is a mixture of specialized asphalts. A hot spray application of an Epoxy Asphalt bond (tack) coat applied to the substrate 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 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 manufacturing, 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, very heavily loaded trucks and more recently, open graded pavements. Epoxy Asphalt is also be referred to as Epoxy Bitumen or Bitumen Modified Epoxy in countries outside of North America.
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 and rutting 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 impermeable (waterproof) pavement that can be opened to traffic quickly.
Epoxy Asphalt has excellent adhesion with the following substrates:
Professional products and training programs for concrete repair, concrete bonding, concrete restoration, concrete coatings and concrete protection including epoxy injection and metering pumps for structural concrete crack repair and control joint fillers in civil engineering, government, commercial, industrial and mro applications. Our epoxy adhesives and coatings are 0 VOC and offer LEED credits including IEQ 4.1, meet ASTM C 881 Types I, II, III, IV, V, VI and VII and fully comply with the Buy America Act for U.S. transportation projects using federal funding.