Cement: Applications, Manufacturing Process, Types and Tests
cement is a binder. It is a substance that hardens and adheres to other materials to bind them together. Cement is one of the most important man-made substances in the world today. In this article, we will look at the cement manufacturing process, its applications, some types of cement and cement testing.
pplications of the Different Types of Cement
Cement can be used alone as grouting material, but its most common application is in mortar and concrete, where it is combined with an inert substance called an aggregate. Mortar refers to cement combined with sand or crushed stones that is no larger than 5 mm in size. It finds uses in holding bricks, blocks, and stone together in buildings or as surface finish renderings.
Concrete is a combination of cement, sand or other fine aggregates, and a coarse aggregate ranging in size from 19 to 25 mm. People use concrete in a wide range of construction applications.
Some applications of the different types of cement include:
- Plastering, masonry construction, pointing, and other purposes.
- Making drain and pipe joints.
- Ensuring that construction is watertight.
- Laying floors, roofs, beams, staircases, and pillars, among other things.
- When a hard surface is necessary to protect exposed surfaces of structures from weather-related damage and certain organic or inorganic pollutants.
- Production of precast pipes, piles, and fence posts, among other things.
- Building of significant engineering constructions such as bridges, culverts, dams, tunnels, and lighthouses, among others.
- Construction of foundations, waterproof flooring, and pathways, among other things.
- Building wells, water tanks, lamp posts, tennis courts, telephone cabins, roads etc.
Raw Ingredients Required for Cement
Cement primarily consists of lime (calcium oxide, CaO), silica (silicon dioxide, SiO2) and alumina (aluminium oxide, Al2O3). The lime comes from a calcareous raw material, whereas the other oxides come from an argillaceous or clayey source. Manufacturers add small amounts of other raw materials, such as clay, iron oxide (Fe2O3), fly ash, Calcium Carbonate (CaCO3), and bauxite to achieve the necessary composition. Different types of cement have different quantities of these ingredients. Lastly, manufacturers add gypsum to the burnt cement clinker during grinding to manage the cement’s setting time.
Cement Manufacturing Process
Cement Manufacturing is a four-step process, that is as follows:
Grinding and crushing
Large revolving, cylindrical ball mills, or tube mills carrying steel grinding balls crush all materials except for soft materials, in two stages. Depending on the procedure, this grinding can be done wet or dry, although, for dry grinding, raw materials may need to be dried in cylindrical, rotating dryers beforehand.
In wash mills, soft materials break down because of vigorous swirling with water, resulting in a fine slurry that passes through screens to eliminate large particles.
In large silos, workers mix raw materials in appropriate quantities to obtain a preliminary approximation of the chemical composition necessary for a specific cement. Agitation and rapid circulation provided by compressed air ensure thorough mixing of the materials in large silos. The wet raw material slurry, which includes 35 to 45 per cent water, is sometimes filtered to reduce the water content to 20 to 30 per cent. This filter cake is then fed into the kiln.
Originally posted on Cement!