Composites consisting mainly of fibers/fabrics and resins (polymers) are manufactured using automated and manual processes. Over 20 different methods of composite component manufacturing are in practice with each having its own advantages, limitations, and capability to produce specific end products such as FRP bars, bridge deck shapes, automobile parts, utility poles, airplane components, and others. Depending on the manufacturing process, fibers/fabrics are wetted and cured with resins by different techniques. During manufacturing, resins are mixed with additives and modifiers (e.g., accelerators, pigments, UV ray inhibitors, fire retardants and others) to achieve proper curing characteristics, viscosity, durability, appearance, and finish. Some composite products are manufactured by using readily available inserts such as metal bolts, brackets, and other accessories. Some of the important parameters that affect short-and long-term properties of composites are:
• Fiber/fabric properties and configurations • Resin properties • Additive and modifier properties • Percent cure of resins and fiber volume content • Process parameters (temperature, pressure, cure time, and surface finish
Several commonly used manufacturing methods are listed in Section 3.2. Among the manufacturing processes listed, pultrusion is used for manufacturing FRP bars and hand lay-up is used for wrapping or bonding FRP fabrics to concrete member surfaces for external strengthening. Other manufacturing methods described in this chapter provide details on their capabilities, advantages, and limitations. Additional details on composite manufacturing methods are available in handbooks and publications related to a particular manufacturing method [ASM 1989, 2001; CSCE 1992; Mallick 1997; Gutowski 1997; Holloway 1990; Peters 1998].