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John Carson—Marketing director, CHOMARAT
John Carson has been the marketing director for CHOMARAT North America for the past 10 years and leads the global commercial effort for C-Grid reinforcements. He serves on the board of directors of AltusGroup, of which CHOMARAT is a founding member. He is a member of the American Concrete Institute, the International Concrete Repair Institute and American Composites Manufacturing Association. Carson is also active in ACMA subgroups: Automotive Composites Alliance, Transportation Structures Council and Green Composites Subcommittee. He will be speaking on carbon fiber reinforcements at the Construction, Corrosion and Infrastructure Conference (CCI), May 9-11 in Las Vegas, sponsored by the American Composites Manufacturers Association.
How can carbon fiber be used to reinforce concrete construction?
Carbon fiber grid has many possibilities for reinforcing concrete structures. Current applications include precast concrete, concrete décor, cast in place, shotcrete (concrete conveyed through a hose), pervious concrete and for repair and rehabilitation uses. It is primarily used as a secondary flexural reinforcement for crack control and for the replacement of temperature steel (welded wire mesh and light steel rebar).
How does carbon meet the requirements for these applications?
Carbon fiber grid is one of the more economical carbon fiber based composite reinforcements in the marketplace today. It comes in roll format up to 8 feet wide, in 1.6 meter shear truss strips, or in cut sheet or custom sizes for certain applications. It is lightweight, easy to handle and place in molds and formwork. For connecting two wyeths of concrete, such as in sandwich walls, carbon fiber grid has been proven as a very effective high strength shear connector.
What challenges are there for carbon fiber to meet these requirements?
Continuing education and knowledge combined with a willingness to change and accept new technology is a constant challenge for carbon fiber reinforcement and composite technology in the construction segment in general. Engineers, architects and specifiers must know how to properly design and manufacture products using composite materials to take full advantage of the myriad of benefits they can provide. Long term durability is but one benefit they provide.
What will it take for more engineers to include composites in their building specifications?
Continuing composites education because once they try it and have success, they generally are repeat users.
Is composite reinforcement an affordable alternative to metal reinforcement?
In some cases, the use of composite reinforcement can be less costly than the material it replaces (stainless steel). However, in many situations, carbon fiber reinforcement for example, is generally more expensive than the carbon steel mesh product currently being used. However, when viewed in a total systems approach, which includes labor and fabrication savings, concrete elimination, insulation benefits and post applied concrete surface treatments, the use of carbon fiber grid systems can be cost neutral to lower cost.
What is the strength and durability of composites to that of traditional building materials?
There have been many published tests and studies done comparing the strength and durability of composite materials in construction applications. We personally conducted many tests on precast concrete elements at outside laboratories and facilities including E-199 fire tests. High strength and corrosion resistance performance advances have been demonstrated.
What do you see ahead for the field of carbon fiber composite uses?
With the return of the economy to a more normal growth mode, I see continued growth and acceptance of composite materials in construction in general and concrete applications specifically displacing conventional material systems for enhanced sustainability and economics.
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