Cement is a soft, fine, powdery type, and grey color substance, it is an indispensable material when constructing a building or infrastructure projects such as residences, factory, school, hotel, underground sewage system, etc. It is a hydraulic binding material that is used to bind materials. Cement will not be dispersed into the water after forming a hard mass when mixing with the water which will increase its strength and hardness. Cement is made of a chemical combination of eight main elements including Lime, Silica, Alumina, Magnesia, Alkaline, Iron Oxide, Calcium Sulfate, Sulfur Trioxide during the production process. These chemical elements are generally extracted from clay, shale, limestone, sand, and iron ore. Cement also can mix with other elements to match our project requirements. When cement is mixed with sand, gravel, and water, it forms concrete; when it is mixed with sand and water, it forms cement plaster; and when it mixed with sand, lime, and water, it forms mortar.
The manufacturing process of cement involves several steps like mining, crushing, drying, grinding, sintering, cement grinding, and packaging. At the beginning of the process, the raw material of cement which mainly are clay and limestone will be extracted by blasting and drilling with the use of mining machinery. The raw materials will be removed and delivered to the crusher after extraction. The limestone will be crushed, mixed with clay, and to reduce its particular size. The raw material will then be sent to the raw mill via blowers for the drying and grinding process. Hot gases then enter into the mill to dry out the raw mix material before entering into the grinding chamber. There will have different sizes of balls which are ranging from 30mm to 90mm in the grinding chamber to grind the raw mix material. After the process of drying and grinding process has completed, only fine materials will be selected and delivered into a multistage cyclone to remove gases from the fine materials. The very fine material is then delivered to the concrete silo. The raw material extracted from the silo, we called it kiln feed. Kiln feed will be conveyed to the preheater kiln for the sintering process. Sintering is the process of using heat to break down the chemical bonds of the raw mater and recombine it into a new compound of a substance called clinker. The feed will be superheated at around 1400 Celsius to form the clinker under this process. Clinker is extremely hot and small after come out of the kiln. The cooling fans in the grate cooler will cool down it to around 120 Celsius. The cooled clinker will be transported to the cement mills where the clinker is to be mixed with other additives for producing certain types of cement products. The ball mill grinds the feed into a fine powder and then will be stored in the concrete silo as cement. When the cement has 150 billion grains and so considered fine cement.
Here are some common types of cement available for our projects:
Portland Cement
Portland cement is one common type of cement and made by most cement manufacturers. It is made with a combination of controlled chemicals such as silicon, iron, calcium, aluminum, and other elements. Portland cement is grey in color, it has a low chemical resistance, medium rate of hardening, strength development, and evolution of heat. We use portland cement to make concrete which is usually composed of around 10% to 15% portland cement, 15% to 20% water, and mixed with 60% to 75% aggregates such as gravel, sand, or crushed stone.
White Cement
White cement is a type of portland cement, it is in white color and typically made of pure white chalk and raw material free Iron oxide. It is more expensive and mainly used for decorative and interior works such as wall putty, precast curtain wall, floor finish, facing slabs, garden path, etc.
Rapid Hardening Cement
Rapid hardening cement is also called High Early Strength Cement, it is able to gain strength faster than ordinary cement. It is a finer ground and has more tri-calcium silicate than the portland cement. With the same water to cement ratio, the strength of rapid hardening cement after three days of application is nearly the same as the portland cement after seven days of application. Its rapid rate of development of strength and shorter period of water curing have made it popular to be used for important structures, underwater works, precast concrete works, road repair.
Sulfate Resistant Cement
Sulfate resistance cement is also known as alkali-resistant cement. It is used when the concrete will have direct contact with the soil where has a high level of Suphate/alkali in the sewage systems, groundwater, platform in the coast, ocean water. It has a low heat of hydration and does not generate too much heat when contacting with the water. Popular applications are raining walls, pile foundation, canals linings, etc.
Water Repellent Cement
Water repellent cement is consists of the rapid hardening cement or ordinary cement with an additional small portion of metal stearates such as calcium or aluminum. It is typically produced with the mixing of water-repelling chemicals which made it able to withstand wet climate and environment. It is suitable to be applied where has direct contact with water such as the construction of the bridge, swimming pool, retaining wall, tank, and other special works.
Expansive Cement
As we know, most of the concrete shrinks when they drying out. Expansive cement can slightly expand and does not shrink during and after the hardening process. It generally contains the Portland cement clinkers with calcium sulfate or tricalcium aluminate. Expansive cement is commonly used as a critical part of sealing joints or other application such as prestressed concrete ducts and grouting anchor bolts
Low Heat Cement
The heat produced during the hydration process will result in cracks for the large body of concrete. Low Heat Cement is manufactured at a low rate during the hydration process and it produces less amount of heat compared with other types of cement. Since the rate of evolution of heat will be less and so it will extend over a longer period, the strength of a low heat cement is the same as the ordinary Portland cement.
Quick Setting Cement
Quick setting cement is produced by reducing the amount of gypsum and adding a small portion of aluminum sulphate. This type of cement required to be placed, mixed and compacted at a very early stage. The initial setting time is 5 minutes and the final setting time is around 30 minutes. Quick setting cement is used for underwater construction.
Portland Pozzolana Cement
Pozzolans cement is manufactured by combining clinkers and pozzolana together. By adding pozzolana in the cement, it can react with the lime liberated in the hydration process and avoid disruption in the concrete. It offers high compressive strength and greater resistance to the water. Portland pozzolana cement is mainly used in underwater and marine construction.
There is a variety of cement available in the market and each of them is made for different purposes and applications. MecHero Malaysia supplies a wide range of cement for meeting your requirements. You can always contact us at +6011-7000 7687 or email us at my.mechero@gmail.com for an inquiry about the cement. As a steel and hardware online supplier in Malaysia, we also supply a wide range of steel material, general hardware, or mechanical components. Tell us your requirements now and we can advise you accordingly.
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