Перевод текста concrete is a composite building material made from the combination of aggregate ( composite ) and a binder such as cement. the most common form of concrete is portland cement concrete, which consists of mineral aggregate ( generally gravel and sand ), portland cement and water. it is commonly believed that concrete dries after mixing and placement. actually, concrete does not solidify because water evaporates, but it is cement that hydrates, gluing the other components together and eventually creating a stone-like material. foundations, freeways, parking structures, bases for gates and fences, etc. when used in the generic sense, this is the material referred to by the term concrete. as concrete has a rather low tensile strength, it is generally strengthened by using steel rods or bars ( known as rebars ). this strengthened concrete is then referred to as reinforced concrete. in order to minimize any air bubbles ( that would weaken the structure ), a vibrator is used to eliminate any air that has been entrained when the liquid concrete mix is poured around the ironwork.
