Composition of cement The composition of cement is what it is made of and what elements it has.
Cement is generally divided into ordinary portland cement, portland cement mixed with mixed materials and special cement. Ordinary Portland cement: limestone, clay and iron ore powder are ground and mixed in proportion. At this time, the mixture is called raw meal. Then it is calcined at the temperature of 1450 degrees, and the calcined product is called clinker. Then the clinker and gypsum are ground and mixed in proportion. It is called cement. Portland cement with mixed materials is to add other substances into ordinary portland cement according to a certain proportion and processing procedures to achieve special effects, such as slag cement, pozzolanic portland cement, fly ash portland cement, composite portland cement and so on. The raw materials of these cements are more active or inactive mixed materials than the original ordinary portland cement. Special cement is somewhat different in material stage and manufacturing process. For example, the raw materials of high alumina cement (aluminate cement) are bauxite and limestone, which are calcined to obtain clinker and then finely ground to become aluminate cement. Other cement with some characteristics is of little use, such as white cement, which is mainly used for decoration projects. The raw materials are pure kaolin, pure quartz sand and pure limestone, and the mature raw materials are calcined at a suitable temperature. Cement also has Si O element, and the main component of glass-ceramic cement is silicate.
What are the main components of cement and when did it come into being?
The raw materials for firing cement clinker are: calcareous raw materials (such as limestone), siliceous raw materials (such as sandstone and silica), aluminum raw materials (such as fly ash and bauxite) and iron raw materials (such as iron ore, sulfuric acid slag and copper slag).
Raw materials for manufacturing cement include clinker, gypsum and mixed materials (such as slag, fly ash, slag, desulfurization gypsum, industrial waste residue, etc.). ).
There are many production equipments: mainly raw meal mills, rotary kilns, coal mills and cement mills, as well as crushers, belt conveyors, belt scales, motors, fans, preheaters, calciners, coolers, bolt conveyors, dust collectors, homogenizing bins, powder separators, roller presses, hoisters, coal injection pipes, rotary feeders, stackers, reclaimers, chain conveyors and so on.
The main chemical components of portland cement are calcium oxide, silica, alumina and iron oxide. There are magnesium oxide, K2O, sodium oxide, SO3 and so on. Its content is about: Cao = 64 ~ 67%, SiO2 = 20 ~ 23%, Al2O3 = 4 ~ 8%, Fe2O3 = 3 ~ 6%.
The main mineral composition of cement clinker is tricalcium silicate (3CaO. SiO3 is abbreviated as C3S) and dicalcium silicate (2CaO). SiO2 is abbreviated as C2S), tetracalcium ferric aluminate (4CaO). Al2O3.Fe2O3 is abbreviated as C4AF) and tricalcium aluminate (3CaO). Al2O3 is abbreviated as C3A). The content is about C3S = 52 ~ 60%, C2S = 22 ~ 28%, C3A = 4 ~ 15%, C4AF = 4 ~ 15%).
The word "cement" is developed from the Latin caementum, which means crushed stone and flaky. The history of cement can be traced back to the mixture of lime and volcanic ash used by the ancient Romans in construction projects. 1796, an Englishman, J. Parker, fired a brown cement from marl, which is called Roman cement or natural cement.
Cement. 1824, British asp Ding burned limestone and clay into cement. After hardening, the color is similar to the stone used in construction in Portland, England, so he was named Portland Cement and obtained a patent. At the beginning of the 20th century, with the improvement of people's living standards, the requirements for construction projects are increasing. While continuously improving portland cement, a number of cements suitable for special construction projects, such as high alumina cement and sulphoaluminate cement, have been successfully developed, and the variety of cement has grown to more than 100.
Main components of cement
Cement is generally divided into ordinary portland cement, portland cement mixed with mixed materials and special cement.
Ordinary Portland cement: limestone, clay and iron ore powder are ground and mixed in proportion, and the mixture at this time is called raw meal. Then it is calcined at about 1450℃, and the calcined product is called clinker. Then the clinker and gypsum are ground together and mixed in proportion, which is called cement.
Portland cement with mixed materials is to add other substances into ordinary portland cement according to a certain proportion and processing procedures to achieve special effects, such as slag cement, pozzolanic portland cement, fly ash portland cement, composite portland cement and so on. The raw materials of these cements are more active or inactive mixed materials than the original ordinary portland cement.
Special cement is somewhat different in material stage and production technology. For example, the raw materials of high alumina cement (aluminate cement) are bauxite and limestone, which are calcined to obtain clinker and then ground into aluminate cement.
Other cement with some characteristics is of little use, such as white cement, which is mainly used for decoration projects. The raw materials are pure kaolin, pure quartz sand and pure limestone, and the mature raw materials are calcined at a suitable temperature.
What is the chemical composition of cement?
Main composition of cement: The main composition is silicate. There are many kinds of cement, and the composition is different. Name and chemical formula of main components of ordinary cement: tricalcium silicate, dicalcium silicate and tricalcium aluminate: 3cao SiO2, 2cao SiO2 and 3cao Al2O3.
A ground material, after adding a proper amount of water, becomes a plastic slurry, which can be hardened not only in air, but also in water, and can firmly bond sand, stone and other materials together to form a solid stone-like hydraulic cementing material. Cement is one of the most widely used building materials and engineering materials among inorganic nonmetallic materials, which are widely used in construction, water conservancy, roads, petroleum, chemical industry and military engineering. In recent years, due to the demand, the cement output of developed countries has basically reached saturation, and the annual cement output tends to be stable or declining, while the cement output of developing countries such as China has increased rapidly. For example, in 1983, the world cement output was 900Mt, while that of China was100 mt.
What is the main composition of cement?
Cement is generally divided into ordinary portland cement, portland cement mixed with mixed materials and special cement.
Ordinary Portland cement: limestone, clay and iron ore powder are ground and mixed in proportion, and the mixture at this time is called raw meal. Then it is calcined at about 1450℃, and the calcined product is called clinker.
Then the clinker and gypsum are ground together and mixed in proportion, which is called cement. Portland cement with mixed materials is to add other substances into ordinary portland cement according to a certain proportion and processing procedures to achieve special effects, such as slag cement, pozzolanic portland cement, fly ash portland cement, composite portland cement and so on.
The raw materials of these cements are more active or inactive mixed materials than the original ordinary portland cement. Special cement is somewhat different in material stage and production technology. For example, the raw materials of high alumina cement (aluminate cement) are bauxite and limestone, which are calcined to obtain clinker and then ground into aluminate cement.
Other cement with some characteristics is of little use, such as white cement, which is mainly used for decoration projects. The raw materials are pure kaolin, pure quartz sand and pure limestone, and the mature raw materials are calcined at a suitable temperature.
What is the composition of cement?
Components and characteristics of five common portland cements (I) PI PII composition of portland cement: 1. Cement clinker and a small amount of gypsum (type I) 2. Cement clinker, mixed materials below 5% and appropriate amount of gypsum (type II) Scope of application: 1. Manufacture of concrete, reinforced concrete and prestressed concrete structures on the ground and in water. Including structures subjected to cyclic freezing and thawing and projects requiring high early strength. 2. The preparation of building mortar is not applicable: 1. Mass concrete project. 2. Projects vulnerable to chemical and seawater erosion. 2. Composition of ordinary cement (P.O.): Portland cement is mixed with 6%~ 15% of active mixed materials or inactive mixed materials below 10%. Scope of application: Not applicable: Portland cement (III) Slag cement (P. S) Composition: Portland cement is mixed with 20%~70% granulated blast furnace slag. Scope of application: 1 Large project 2. High temperature workshop and concrete structure with heat and fire resistance requirements. Steam curing assembly 4. General underground and water concrete and reinforced concrete structures 5. Projects with sulfate resistance requirements. . Not suitable for building mortar: 1. Concrete engineering requiring high early strength. Concrete engineering with frost resistance requirements (4) Composition of pozzolanic cement (P P): 20%~50% pozzolanic mixture is added to portland cement. Scope of application: 1 Underground and underwater mass concrete structures II. Projects with impermeability requirements. Steam curing of engineering components 4. Projects with sulfate resistance requirements. Ordinary concrete and reinforced concrete engineering. Not suitable for preparing building mortar: 1. Concrete engineering requiring high early strength. Concrete engineering with frost resistance requirements. Concrete engineering in dry environment. Projects with wear resistance requirements. (5) Composition of fly ash cement: 20%~40% fly ash is added to portland cement. Scope of application: 1 Above-ground, underground, underwater and large-scale concrete engineering. 2. Parts cured by steam. 4. Components with high crack resistance requirements. 5. General concrete engineering. 6. Not suitable for preparing building mortar.
What is the main composition of Portland cement?
Portland cement
The hydraulic cementing materials made of calcium silicate, limestone or less than 5% granulated blast furnace slag and appropriate amount of gypsum are collectively called portland cement. Internationally known as Portland cement.
The main mineral components of Portland cement are tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium ferric aluminate. Tricalcium silicate determines the strength of Portland cement around; It takes four weeks for dicalcium silicate to exert its strength, and it will reach the strength around tricalcium silicate in about one year. The strength of tricalcium aluminate is fast, but low, which plays a certain role in the strength of portland cement in 1 ~ 3 days or a little longer; The strength of tetracalcium ferrite also develops rapidly, but the strength is low, which makes little contribution to the strength of portland cement.
This kind of cement includes all kinds of portland cement without or with mixed materials. According to the mixing situation of mixed materials, China is divided into the following five categories.
1. Pure Portland cement
2. Ordinary Portland cement
3. Slag Portland cement
4. Volcanic pozzolanic Portland cement
5. Fly ash portland cement
Main components of cement
Cement is generally divided into ordinary portland cement, portland cement mixed with mixed materials and special cement.
Ordinary Portland cement: limestone, clay and iron ore powder are ground and mixed in proportion, and the mixture at this time is called raw meal. Then it is calcined at about 1450℃, and the calcined product is called clinker.
Then the clinker and gypsum are ground together and mixed in proportion, which is called cement. Portland cement with mixed materials is to add other substances into ordinary portland cement according to a certain proportion and processing procedures to achieve special effects, such as slag cement, pozzolanic portland cement, fly ash portland cement, composite portland cement and so on.
The raw materials of these cements are more active or inactive mixed materials than the original ordinary portland cement. Special cement is somewhat different in material stage and production technology. For example, the raw materials of high alumina cement (aluminate cement) are bauxite and limestone, which are calcined to obtain clinker and then ground into aluminate cement.
Other cement with some characteristics is of little use, such as white cement, which is mainly used for decoration projects. The raw materials are pure kaolin, pure quartz sand and pure limestone, and the mature raw materials are calcined at a suitable temperature.