A carbon grid is a form of weaved, carbon-based fiber that is used as a reinforcing mesh in building construction, such as in concrete, where it can replace steel mesh or rebar. It offers advantages over traditional steel reinforcement in that it can be placed much closer to the surface of a material, and is lighter in weight. While concrete reinforcement is the primary use area, carbon grid is also used in many other types of building materials, as well as in structural components for aircraft, ships, and cars. Another application of carbon fiber grid is the use of the material as a reinforcing agent in ion engine design, which reduces the weight of such spacecraft engines and increases their thrust capacity.
The material used to make a carbon grid is more than just carbon itself, and includes what is known as fiber-reinforced polymer (FRP), a composite of various plastic compounds such as polyester and epoxy, along with fiberglass fiber and carbon. Other synthetic fibers aside from just fiberglass are also used, such as aramid, a name derived from the words "aromatic polyamide." Aramid is a key component of body armor and ballistic armor for vehicles in military use. This combination of fibers and plastics along with carbon is often referred to as carbon fiber-reinforced polymer (CFRP).
One of the key areas of industry where carbon grid material has become a crucial element is in the maintenance of bridges. Bridges composed of concrete that were reinforced with steel when they were built are subject to corrosion over time, which can make them vulnerable to excessive stress during such weather elements as storms and earthquakes. Steel mesh as an external reinforcing mechanism has also been proven to have limited value. In this application, the carbon grid is not embedded in the concrete of the bridge, which has already set, but is used as an external fabric wrap to reinforce the completed structure. Regions where carbon grid have been used to reinforce bridge columns as of 2003, such as in Florida in the US, have shown an increased strength of the bridge columns of up to 420% versus before they had reinforcing mesh of any kind applied.
In the 1980s, carbon grid material first began to migrate to the commercial sector from aerospace and military applications. Its initial high cost made it prohibitive for every day construction use, but, as production volume has increased, prices have come down. It is now used to reinforce ornamental concrete planters and other heavy duty, non-essential products in the consumer market. One of the main drawbacks to the composite fiber in building construction is that it does not have the diverse yield characteristics that steel does under stress or changing climate conditions, so building methodologies have had to be adjusted to accommodate this change when it is used.