Over the next few months, interest in the next round of infrastructure repair projects could bring some much needed work to contractors who treat concrete surfaces. One segment of shovel-ready projects could be the resurfacing of the thousands of concrete bridge decks around the country.
This could be especially true for a type of treatments known as epoxy surface polymer overlays. This system is gaining more attention from departments of transportation and engineering specifiers. But entering this market segment could be a daunting task for a contractor who may not be aware of all the ins and outs of the overlay installation process.
Fortunately for contractors and specifiers who are just becoming aware of this product's attributes, the American Concrete Institute has published a document to familiarize all parties. ACI 548.9-08, Specification for Type ES (Epoxy Slurry) Polymer Overlay for Bridge and Parking Garage Decks, was republished about a year ago. It includes the current thoughts on how to properly use this product.
There are many types of epoxy overlay materials. Type ES polymer overlay incorporates low-modulus epoxy-based slurry and selected aggregate to create a wear surface.
The overlay is placed in two steps. First the contractor applies the polymer slurry to the surface. Then he broadcasts aggregate into the slurry before curing. The installed system produces a flexible, skid-resistant, and water-resistant overlay. It is gaining acceptance for both new construction and rehabilitation.
Developed by a committee of manufacturers, contractors, and researchers, and chaired by Mike Stenko, this specification outlines how to properly install epoxy slurry overlay on bridge and parking decks. It provides the basic outline of the installation process, beginning with material selection and ending with road reopening.
The six-page document includes a great deal of useful information. It provides tables listing the properties of mixed, uncured epoxy binder, the physical properties of cured epoxy binder, and properties of Type ES polymer overlay. It also outlines proper aggregate gradations and quality requirements.
The execution section outlines the necessary procedures to be completed before starting the job. It outlines proper surface prep requirements and provides guidance on how to properly mix, apply, and cure the material during the job. After curing, the document indicates when to remove excess aggregate, cut joints, and open to service.
The document has two purposes. Contractors who plan to bid on a project can provide the document to the specifying engineer during the planning process to be included in its entirety in the project specification. Or they can it in reviewing the final project specification as a comparison to be sure that all parts were incorporated to eliminate any misunderstandings.
While not part of the specification language, the document also helps the owner and engineer ensure the project's success by including two checklists. These short lists assist the specifier in selecting and specifying project requirements. The Mandatory Requirements Checklist indicates work requirements regarding specific qualities, procedures, materials, and performance criteria that are not defined in ACI Specification 548.9. The Submittals Checklist identifies specifier choices for information or data to be provided by the contractor before, during, or after construction.
To order 548.9-08: Specification for Type ES (Epoxy Slurry) Polymer Overlays for Bridge and Parking Garage Decks, visit the ACI bookstore at www.concrete.org.