Yahoo: Concrete made from algae? Chicago firm offers a closer look at ‘bio-blocks,’ a zero-carbon alternative
Concrete made from algae? Chicago firm offers a closer look at ‘bio-blocks,’ a zero-carbon alternative
Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid. It is the second-most-used substance (after water), [1] the most widely used building material, [2] and the most-manufactured material in the world. [3]
concrete, in construction, structural material consisting of a hard, chemically inert particulate substance, known as aggregate (usually sand and gravel), that is bonded together by cement and water. Among the ancient Assyrians and Babylonians, the bonding substance most often used was clay.
Concrete is an artificial construction material prepared by mixing a binding material (cement or lime), fine aggregate (sand), coarse aggregate (stone chips, brick chips, or gravel), and water in proper proportion. Admixtures may be added to improve specific properties of concrete.
In its simplest form, concrete is a mixture of paste and aggregates (sand & rock). The paste, composed of cement and water, coats the surface of the fine (sand) and coarse aggregates (rocks) and binds them together into a rock-like mass known as concrete.
Concrete is made up of three basic components: water, aggregate (rock, sand, or gravel) and Portland cement. Cement, usually in powder form, acts as a binding agent when mixed with water and aggregates. This combination, or concrete mix, will be poured and harden into the durable material with which we are all familiar.
We can trace "concrete" back to the Latin verb concrescere, meaning "to grow together." Appropriately, when it first entered English "concrete" could mean "connected by growth." Logicians and grammarians also applied "concrete" to words that expressed a quality viewed as being united with the thing it describes.