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Cement

How Portland cement is made??

Bricklayer Joseph Asp din of Leeds, England first made portland cement early in the 19th century by burning powdered limestone and clay in his kitchen stove.
Portland cement, the basic ingredient of concrete, is a closely controlled chemical combination of calcium, silicon, aluminum, iron and small amounts of other ingredients to which gypsum is added in the final grinding process to regulate the setting time of the concrete. Lime and silica make up about 85% of the mass. Common among the materials used in its manufacture are limestone, shells, and chalk or marl combined with shale, clay, slate or blast furnace slag, silica sand, and iron ore.

Each step in manufacture of portland cement is checked by frequent chemical and physical tests in plant laboratories. The finished product is also analyzed and tested to ensure... [Read More]