FRP systems come in a variety of forms, including wet layup systems and precured systems. 

FRP system forms can be categorized based on how they are delivered to the site and installed. The FRP system and its form should be selected based on the acceptable transfer of structural loads and the ease ofapplication.

Wet layup systems

Wet layup FRP systems consist of dry unidirectional or multidirectional fber sheets or fabrics impregnated with a saturating resin on site.

The saturating resin, along with the compatible primer and putty, bonds the FRP sheets to the concrete surface. Wet layup systems are saturated on site and cured in place. The common types of fber reinforcement used in wet layup systems are as follows:

1. Dry unidirectional fber sheets where the fibers run predominantly in one planar direction. The specifcations for unidirectional carbon fber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP) wet layup systems.

2. Dry multidirectional fber sheets or fabrics where the fbers are oriented in at least two planar directions.

Another possible system may include dry fiber tows that are impregnated during installation and wound or otherwise mechanically applied to the concrete surface. However, this system is not commonly used.

Prepreg systems

Prepreg FRP systems consist of partially cured unidirectional or multidirectional fber sheets or fabrics that are preimpregnated with a saturating resin in the manufacturer's facility. Prepreg systems are bonded to the concrete surface with or without an additional resin application, depending on specifc system requirements. Prepreg systems are saturated off site and, like wet layup systems, cured in place.Prepreg systems usually require additional heating or moisture for curing. Prepreg system manufacturers should be consulted for storage and shelf-life recommendations and curing procedures. The common types of prepreg FRP systems are as follows:

1.Preimpregnated unidirectional fber sheets where the fibers run predominantly in one planar direction.

2. Preimpregnated multidirectional fber sheets or fabrics where the fbers are oriented in at least two planar directions.

Preimpregnated fber tows that are wound or otherwise mechanically applied to the concrete surface have been developed. However, this system is not commonly used.

Precured systems

Precured FRP systems consist of a wide variety of composite shapes manufactured off site.

Typically, an adhesive, along with the primer and putty, is used to bond the precured shapes to the concrete surface. The system manufacturer should be consulted for recommended installation procedures. Three common types of precured systems are:

1. Precured unidirectional laminate sheets, typically manufactured using a pultrusion process, delivered to the site in the form of large flat stock or as thin plates coiled on a roll

2. Precured multidirectional grids, typically delivered to the site coiled on a roll

3.Precured shells, typically delivered to the site in the form of shell segments cut longitudinally so they can be opened and fitted around columns or other members; multiple shell layers are bonded to the concrete and to each other to provide confinement

Near-surface-mounted (NSM)systems

Surface embedded NSM FRP systems consist of circular bars or narrow rectangular plates installed and bonded into grooves made on the concrete surface.A suitable adhesive is used to bond the FRP bar or plate into the groove and is cured in place. The NSM system manufacturer should be consulted for recommended adhesives. Two common FRP types used for NSM applications are:

1. Bars usually manufactured using pultrusion processes, typically delivered to the site in the form of single bars or in a roll, depending on bar diameter

2. Plates usually manufactured using pultrusion processes, typically delivered to the site in a roll