Composite Material

What defines a composite is that the constituents remain physically distinct within the finished material rather than dissolving into one another as they would in an alloy or solution. The usual description separates a reinforcement, which carries load, from a matrix, which binds the reinforcement, transfers stress between its elements and protects it from the environment. Fibre-reinforced polymers pair glass or carbon fibres with an epoxy or polyester matrix and are selected chiefly for specific strength and specific stiffness, the strength and stiffness per unit density. Concrete is the oldest large-scale example, aggregate embedded in a cement matrix, and reinforced concrete adds steel to compensate for the low tensile strength of the mineral phase. Performance depends heavily on the interfacial bond, which is where composites most often fail.