Epoxy polymer concrete quickly becoming preferred alternative to polyester polymer concrete for bridge restoration and repair projects. Improved contractor safety and shortened road closures contributing to DOT approvals nationwide.
Albuquerque, NM (PRWEB) - Engineers are welcoming EPC Overlay, an epoxy polymer concrete polymer overlay system from E-Chem, as an emerging alternative to polyester polymer concrete (PPC) for bridge deck preservation and restoration.
For more than 30 years, the use of polyester polymer concrete (PPC) has been commonplace on bridge deck repair. While not typically used in the initial construction of these structures, PPC has provided a means by which to repair surface cracking and/or replace the topmost surface of a bridge deck, worn over the years by automotive and truck traffic and chemical roadway treatments. While these products have filled this need, they have not done so without some drawbacks.
The new technology brings an impressive list of benefits both to contractors, DOTs, and engineers. First, EPC allows for short road closures. PPC does not adhere well to concrete on its own, so a bonding agent is used. High molecular weight methacrylate (HMWM) is laid down as a primer prior to installation of the PPC. This primer is moisture sensitive, so a very low moisture level is required before work can commence. EPC, on the other hand, adheres to nearly anything, and so requires no such bonding agent. That is one fewer step in the process, speeding time to completion. Epoxy polymer concrete is also moisture insensitive (Surface Saturated Dry) - again, lending itself to shorter closures and a lower incidence of weather delays.
Use of polyester polymers also comes with some inherent safety risks. PPC contains styrene monomer, a VOC that releases vapors that are irritating to the eyes and mucous membranes. PPC is flammable and contains HAPs, or hazardous air pollutants (Group 2B Cancer Causing Agent) as categorized by the EPA and the Clean Air Act. Any project using PPC must adhere to stringent safety regulations, employ the use of personal protective gear, and the services of an industrial hygienist are typically retained to ensure the safety of residents, the travelling public, and workers in nearby areas. EPC Overlay is non-flammable, 100% solids, two-to-one epoxy. It contains no VOCs, so workers can breathe normally while starting work right away.
“EPC Overlay provides a durable bridge deck surface that prevents chemical intrusion and provides a wearable surface service life of up to 25 years,” says Ray Breer, Vice President of E-Chem, manufacturer of EPC Overlay based in Albuquerque, New Mexico. “We’re keeping all the strength requirements while removing the liability and hazards associated with PPC.”
Several states have approved, and several others are poised to approve EPC to perform these restoration and repair functions. Testing shows EPC to meet or exceed the requirements for compressive strength, bonding and endurance used by Departments of Transportation when listing products on their Approved Materials Lists. EPC products are currently listed on AMLs in New York, North Carolina, Nebraska and New Mexico, and a long list of states are evaluating EPC for inclusion. Many jobs are being approved on a case-by-case basis as contractors and engineers specifically request EPC as an acceptable alternative to previously specified polyesters.
EPC Overlay consists of an epoxy binder mixed with sand and a coarse aggregate. It is easy to use and can be mixed for a smaller project in a 5-gallon bucket. For larger projects, a volumetric mixing truck is ideal, mixing the part A and B of the epoxy binder and spreading appropriate volume of sand and aggregate. A volumetric mixing truck can put out 12 yards of fully mixed EPC in 45 minutes, so a typical large bridge project can be resurfaced, cured and ready for traffic in an 8-hour closure window.
What about availability? With recent disruption in global supply chain, can contractors get their hands on EPC? The answer is a resounding “Yes!” according to James High, President of E-Chem. “While many of our competitors rely on foreign suppliers, we’ve maintained solid relationships with domestic manufacturers. China is still not at full capacity, and Korea is supplying China, leaving some of the big players completely unable to supply jobsites. We’re paying a bit more, but we are flush with raw material and can ship large orders of EPC Overlay today.”
E-Chem specializes in the design, manufacture, and supply of epoxy polymer products for concrete and is a subsidiary of Adhesives Technology Corp, a Meridian Adhesives Group Company. For more information on EPC Overlay from E-Chem, please visit https://e-chem.net/products/#overlays