Done by: free Syria group Mohamed masry Mohamed abdulhamed Maayof kayed Hozayfa mohamed

Composite materials for construction, engineering, and other similar applications are formed by combining two or more materials in such a way that the constituents of the composite materials are still distinguishable, and not fully blended. One example of a composite material is concrete, which uses cement as a binding material in combination with gravel as a reinforcement. In many cases, concrete uses rebar as a second reinforcement, making it a three-phase composite, because of the three elements involved

 1- Concrete Concrete is a composite construction material composed primarily of aggregate, cement, and water. There are many formulations, which provide varied properties. The aggregate is generally a coarse gravel or crushed rocks such as limestone, or granite, along with a fine aggregate such as sand. The cement, commonly Portland cement, and other cementitious materials such as fly ash and slag cement, serve as a binder for the aggregate. Various chemical admixtures are also added to achieve varied properties. Water is then mixed with this dry composite, which enables it to be shaped (typically poured) and then solidified and hardened into rock-hard strength through a chemical process called hydration. The water reacts with the cement, which bonds the other components together, eventually creating a robust stone- like material. Concrete has relatively high compressive strength, but much lower tensile strength. For this reason it is usually reinforced with materials that are strong in tension (often steel). Concrete can be damaged by many processes, such as the freezing of trapped water.

 2- Bath Tubs and Shower Stalls If your shower stall or bathtub is not porcelain, chances are good that it is a fiberglass reinforced composite tub. Many fiberglass bathtubs and showers are first gel coated, and then reinforced with glass fiber and polyester resin. Most often, these tubs are manufactured through an open molding process, usually either chopped gun roving, or layers of chopped strand mat. More recently, FRP tubs have been manufactured using the RTM process (Resin Transfer Molding), where positive pressure pushes thermoset resin through a two sided hard mold.