Everything You Need to Know About Cement

 For the production of cement, the first stage is the mining of its basic ingredients which are limestone, marl, and clay in quarries. There are various ways to extract the raw materials such as digging or blasting. Once these raw materials are collected, the next step that follows would be to crush them into smaller pieces. This mailing process includes the addition of minerals that are required to ensure the correct chemical composition for the final cement product. The fine powder-like result from the milling process is then sent to the kiln where it would be heated at temperatures around 1500°C. At these high temperatures, the raw meal converts into smaller granules that have gone through chemical reactions and are called clinkers.

Once the clinker is done, it is stored to cool down and get ready for the next stage where it would be mixed with gypsum. Around 3 to 5 percent gypsum is added to the clinker to regulate the setting of the cement. Once the addition is done, it is finely grounded and other applicable additions are added to the mix. Each of these additions carries some properties that can give specific features to the cement such as easier workability, high-quality finish, reduced permeability, and so on. After the completion of this stage, the final product called cement is ready to be shipped. They are stored in silos which are then distributed to various plants and dealers

What are the types of cement available in the market?

Cement is a versatile construction material that has significantly contributed to the industrialization and urbanization of our current society. Being an essential part of the whole construction process, it has diversified into different types which are used depending on their specific features and environmental needs. Some of the most common types of cement available in India are as follows:

OPC – 53 Grade

Ordinary Portland cement (OPC) 53 grade is suitable for a wide variety of civil construction. It successfully passes the criteria of IS:12269-1987 Grade. This type of cement is known for its high strength and durability. It has the right particle size distribution and good crystallized structure which benefits the stability of the mixture. As it is high-strength cement, it is popularly used in the construction of bridges, chimneys, concrete roads, skyscrapers, and other heavy load-bearing structures. Compared to any other type of cement, OPC 53 grade is superior for its early strength. It does not increase a lot after 28 days. With the help of good supervision and controlled quality assurance measures, the risks of micro-cracks due to higher heat of hydration can be avoided.

OPC 43 Grade

Ordinary Portland Cement 43 Grade refers to the type of cement which is expected to have comprehensive strength of 43 MPa in a cube cast by 28 days. It passes the requirement of IS:8112. Being slightly different from OPC 53 grade cement, this type of cement would continue to gain strength after 28 days as well. Though It should be noted dark the ultimate strength for both OPC 53 and 43-grade blocks of cement would be the same. With OPC 43 grade cement, that would be medium heat of hydration. As this type of cement does not rapidly harden, it is used for construction purposes like plastering or flooring. It is also popularly used in the manufacturing of precast items such as pipes, blocks, tiles, etc.

PPC

Portland Pozzolana Cement (PPC) is made by using pozzolanic materials which are siliceous and aluminous. These materials do not have cementitious properties on their own but when they come in presence of moisture and are chemically reacted with calcium hydroxide at ordinary temperature, they can form compounds that would have cementitious properties. Common types of pozzolanic materials may include calcined clay, volcanic ash, silica fumes, or fly ash. PPC material is widely used in plaster and brickwork, Marine work, mass concrete work, and RCC work in residential and construction buildings. As this material has less permeability of water, it is highly durable for concrete structures. It also has higher resistance against sulfates, alkalis, chlorides, or chemicals. They have a low heat of hydration and are easier to work with. Also, it should be noted that PPC is popularly used to achieve a smooth surface finish.