Glass has been the predominant fiber for many civil engineering applications because of an economical balance of cost and specific strength properties.
Glass fibers are commercially available in E-Glass formulation (for electrical grade), the most widely used general-purpose form of composite reinforcement, high strength S-2® glass and ECR glass (a modified E Glass which provides improved acid resistance).
Other glass fiber compositions include AR, R and Te.
Although considerably more expensive than glass, other fibers including carbon and aramid, are used for their strength or modulus properties or in special situations as hybrids with glass.
E-Glass—A family of calcium-alumina-silicate glasses which has the following certified chemical compositions and which is used for general-purpose molding and virtually all electrical applications. E-glass comprises approximately 80 to 90 percent of the glass fiber commercial production.
The nomenclature “ECR-glass” is used for boron-free modified E-glass compositions. This formulation offers improved resistance to corrosion by most acids.
S-Glass—Is a proprietary magnesium alumino-silicate formulation that achieves high strength, as well as higher temperature performance.
S-Glass and S-2 Glass have the same composition, but use different surface treatments.
Sglass is the most expensive form of glass fiber reinforcement and is produced under specific quality control and sampling procedures to meet military specifications.
C-Glass—Has a soda-lime-borosilicate composition and is used for its chemical stability in corrosive environments.
It is often used in composites that contact or contain acidic materials for corrosion-resistant service in the chemical processing industry.