Which of the following is an example of a fiber-reinforced composite?

• A. Concrete with cement matrix and gravel
• B. Fiber-glass consisting of continuous glass filaments in a polymer matrix
• C. Steel alloy with ceramic particles
• D. Wood with glue

Answer: (B)

Fiber-reinforced composites are built by embedding high-aspect-ratio fibers in a surrounding matrix; the fibers carry load along their length while the matrix binds them and transfers stresses. The option with continuous glass filaments in a polymer matrix matches this structure exactly, making it a classic fiber-reinforced composite: the glass fibers provide strength and stiffness, and the polymer resin holds them in place and distributes the load. In contrast, concrete with cement paste and gravel uses granular aggregates rather than fibrous reinforcement; a steel alloy with ceramic particles is a metal-matrix composite with particle reinforcement (not fibers); and wood bonded with glue is a laminated or bonded wood product, not a true fiber-reinforced composite with continuous fiber reinforcement.