Composite building materials are formed from two or more distinctly different materials. When combined, the properties of the newly formed material are superior to those of the individual components. The combination process is a physical practice rather than a chemical one, so composite materials exhibit the combined properties of their component materials.
Composite materials contain two types of constituent materials, matrix and reinforcing materials. At least one variety of each type is necessary. The matrix material surrounds and supports other constituents by maintaining their relative positions. The reinforcing material imparts special physical properties, such as electrical and mechanical properties, to improve the properties of the matrix.
Composite materials are noted for their characteristic properties such as high structural strength, light weight, resistance to chemical wear and corrosion, toughness (impact resistance), mechanical stiffness, heat resistance, and ease of processing (fabrication). Most materials are cost-effective, cause less public nuisance, and require lower long-term maintenance and replacement costs.
Commonly used forms are fiber-reinforced plastics (fiberglass, thermoplastic composites, thermosetting composites, etc.), metal matrix composites (white cast iron, hard metal, and metal intermetallic laminate), ceramic matrix composites (cement, carbon -reinforced carbon, etc.) and engineered wood (plywood, oriented strand board and pykrete).
Composite materials are found in nature. An example is wood that contains cellulose fibers reinforced by a polymeric substance such as lignin. Wood is one of the most common materials used in the construction industry. Straw and mud in the form of bricks are the most primitive composite building materials. Other varieties are organic matrix composites or ceramic aggregates (syntactic foam and asphalt concrete).
The concretes are manufactured from the combination of aggregates and cement binder. They are used in the manufacture of highways/roads and all building structures. Natural fiber composites (NFC) are made from natural fibers like wood or hemp with man-made materials like recycled plastics. They are generally inexpensive and can be easily molded into sheets, boards, and frames. NFCs are used as an alternative to wood in fences, railings, floors, roofs, etc. Composite materials like faux granite and cultured marble sinks are also widely used.
