Carbon Fiber Reinforced Polymers (CFRP)

Epoxy Design CFRP on Beam

When conventional reinforcement and strengthening methods fail to provide the necessary support, Carbon Fiber Reinforced Polymer (CRFP) may be the solution. CRFP consists of carbon fiber, to provide the strength, and epoxy to bind the reinforcements together.

Existing capacity and calculated deficiency of the specific structural elements must be known In order to correctly place and structurally reinforce existing structures with carbon fiber strengthening. This process and design in accordance with ACI-440 should always be performed, by a structural engineer who can provide stamped design plans for the correct placement of the  carbon fiber strengthening reinforced polymer. The engineers confirming calculations are based on the difference between the initial load design and any deficiency or desired load increase. CFRP strengthening should be considered as secondary to existing reinforcement.

CFRP Applications

One of the most important steps when applying any CFRP product is the placement onto properly prepared surfaces. It is required to abrasive grit blast or ultra-high pressure hydro blast the concrete surface to obtain a course sandpaper-like profile. Epoxy bonded pull-off metal dollies to measure tensile strength placed at selected surface locations must yield results greater than 200 psi. This assures sound substrate to bond the CFRP.  Anything less requires additional surface profile and re-testing before proceeding with CFRP application. Epoxy primers designed to penetrate the substrate and epoxy putty applied to fill small anomalies, provide the bonding adhesive for carbon fabric and strips. Using the modified “dry method” described in ACI-440, the first layer of fabric or strip is applied with the CFRP surface rolled and squeegeed to remove air. In-place carbon fabric is monolithically bonded and encapsulated with a second application of epoxy resin to the exposed fabric surface. Once cured the material surface may receive a UV protective coating and/or fireproofing material.

Some additional considerations for every application:

  • Surface temperatures, concrete moisture and humidity.
  • Structurally repair all defects (spalls, cracks, corrosion) in concrete prior to CFRP application.
  • Perform button pull off bond strength to assure of proper surface preparation
  • Do not dilute, add to or alter the resin products
  • Cure times between fabric layers, and pull testing cured fabric coupons

Common Applications for CRFP include:

CFRP CSI Codes

  • 03 25 19 Carbon Fiber-Reinforced Polymer Reinforcing

Epoxy Design Systems offers high-quality carbon FRP installation services to the United States and international clients. We take pride in providing efficient work with industry-leading customer service. Give us a call today at 713-461-8733 or contact us online for a consultation.