Detailed Solution. Rapid Hardening cement has a maximum percentage of C 3 S.

Which has maximum percentage in composition of cement?

The cement contains 35 to 40 percent lime, 40 to 50 percent alumina, up to 15 percent iron oxides, and preferably not more than about 6 percent silica. The principal cementing compound is calcium aluminate (CaO · Al 2 O 3 ).

What is the percentage of C3S in cement?

Tricalcium silicate and dicalcium silicate are the most important compounds responsible for strength. Together they constitute 70 to 80 per cent of cement. The average C3S content in modern cement is about 45 per cent and that of C2S is about 25 per cent.

What is the percentage composition of cement?

(A)- CaO: 40-50%, SiO2: 30-40%, Al2O3and Fe2O3: 10-20% (B)- CaO: 50-60%, SiO2: 29-25%, Al2O3: 5-10%, MgO: 2-3%, Fe2O3: 1-2% and SO2: 1-2% (C)- SiO2: 40-50%, CaO: 30-40%, Al2O3: 10-20%

What is the percentage of gypsum in cement?

The cement manufacturing industry is the major consumer of gypsum, which is added to the clinker in a percentage of 3–5 wt%,.

What does C3A do in cement?

The cement tricalcium aluminate (C3A) content is one of the most important factors affecting the cement-water reducing admixture compatibility. Tricalcium aluminate is the most highly reactive phase in clinker and the one with the greatest affinity for superplasticizer admixtures.

What is the role of C2S in cement?

1. Introduction – Dicalcium silicate (Ca 2 SiO 4, C2S) cement has been developed as a new type of bone cement for the restoration of osseous and dental defect, As an important constituent of Portland cement, C2S possesses hydraulic property and can react with water or aqueous solution to form calcium silicate hydrate (C-S-H) as main hydration product, which contributes to the self-setting property and spontaneously increasing strength of the material.

The C2S paste can be implanted at the defect site through injection, thus avoiding large surgery openings. Similar to other silicate-based bioactive materials, e.g., calcium silicate and bioactive glass, C2S can induce bone-like apatite mineralization in simulated body fluid, Moreover, several studies have demonstrated that C2S could support the proliferation and differentiation of osteo-related cells, due to the release of Ca and Si,

However, it may be not enough to repair bone tissues with large defect size and poor osteogenic ability through C2S alone, as previous studies indicated that calcium silicate show limited effect on restoration of osteoporotic bone tissue, Thus, it is necessary to find solutions to improve the osteogenic ability of C2S, especially on occasions of repairing bone tissue with poor osteogenic ability.

Sr is the second main group element in the periodic table, and is well-known for its important role in bone regeneration. It has been well established both in research and clinical application that Sr element could significantly promote bone regeneration and inhibit bone resorption, The favorable effect of Sr on bone metabolism leads to a great interest in the study of Sr-incorporated materials, such as Sr-substituted hydroxyapatite (Sr-HA), bioactive glass (Sr-BG) and calcium silicate (Sr-CS),

Previous studies suggested that silicate bioceramics incorporated with Sr element possessed better performance by enhancing bone regeneration and suppressing bone resorption, which indicated that Sr could improve osteogenic activity of silicate bioceramics.

However, to our knowledge, the effect of Sr in silicate-based bone cement has not been well investigated. C2S powder can be synthesized by different methods according to literature report, including solid state sintering and the sol-gel method, Solid state sintering with CaO and SiO 2 as raw materials tends to leave CaO residues, and its sintering temperature is higher than that of the so-gel method.

The sol-gel method can also cause CaO impurities. In the present study, we propose a chemical co-precipitation method for the preparation of C2S, which is expected to produce fine and pure C2S powders at relatively low sintering temperature. Considering the self-setting and biological properties of C2S and the osteo-stimulation properties of Sr element, the incorporation of Sr into C2S may lead to the development of self-setting bone cement with enhanced bone regeneration ability.

Therefore, the aim of this study is to synthesize Sr-incorporated C2S (Sr-C2S) and investigate the effect of Sr incorporation on the self-setting and biological properties of the bone cements. The self-setting properties of Sr-C2S bone cements were evaluated in terms of their setting times and compressive strength after hydration.

The apatite mineralization ability, cytocompatibility and ALP differentiation activity of Sr-C2S bone cements were investigated and compared with those of C2S bone cement in order to confirm the biological benefit of Sr-incorporation.

What is C3S and C3A?

Master of Science at University of Trondheim (NTH), Norway – Published Nov 25, 2015 C3S is the main contributor to Strength of cured Concrete in early phases. C3S & C3A are the main contributors to Heat in the early phases. C3A develops approximately 840 Joules/ gram and C3S 500 Joules / gram.

Cement used in Concrete contains approximately 5 times as much C3S as C3A. Thus C3S is the main contributor to the Heat Development as well. To Predict Temperature & Strength Development, C3S & C3A content must be stable! But known Regulations does not specify limits! It turns out that C3S content may vary as much as 22% between suppliers and even between batches from the same supplier.

C3A content may vary as much as 16%! (1) HPC-09 v6 has means of Discrepancy Detection that reveals these Concrete Mix variations and provides Safe Maturity Calculations ! HPC-09 v6 combined with the Quality Control Regime of the plant provides the best Quality Control of your end product.

1. Variation in Cement Properties and Its Effect on Quality of Concrete, Thushara PRIYADARSHANA and Ranjith DISSANAYAKE, University of Peradeniya, 20400, Sri Lanka
2. “Integrated Materials and Construction Practices for Concrete Pavement”. A State-of-the-Practice Manual, FHWA Publication No. HIF-07-004, December 2006
3. “Predicting Temperature Rise and Thermal Cracking in Concrete”. Michael Edward Robbins 2007

• What are the main composition of cement?

  Visit ShapedbyConcrete.com to learn more about how cement and concrete shape the world around us. Portland cement is the basic ingredient of concrete. Concrete is formed when portland cement creates a paste with water that binds with sand and rock to harden.

  • Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients.
  • Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.

  These ingredients, when heated at high temperatures form a rock-like substance that is ground into the fine powder that we commonly think of as cement. Bricklayer Joseph Aspdin of Leeds, England first made portland cement early in the 19th century by burning powdered limestone and clay in his kitchen stove.

  • With this crude method, he laid the foundation for an industry that annually processes literally mountains of limestone, clay, cement rock, and other materials into a powder so fine it will pass through a sieve capable of holding water.
  • Cement plant laboratories check each step in the manufacture of portland cement by frequent chemical and physical tests.

  The labs also analyze and test the finished product to ensure that it complies with all industry specifications. The most common way to manufacture portland cement is through a dry method. The first step is to quarry the principal raw materials, mainly limestone, clay, and other materials.

  After quarrying the rock is crushed. This involves several stages. The first crushing reduces the rock to a maximum size of about 6 inches. The rock then goes to secondary crushers or hammer mills for reduction to about 3 inches or smaller. The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed, and fed to a cement kiln.

  The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge cylindrical steel rotary kilns lined with special firebrick. Kilns are frequently as much as 12 feet in diameter—large enough to accommodate an automobile and longer in many instances than the height of a 40-story building.

  The large kilns are mounted with the axis inclined slightly from the horizontal. The finely ground raw material or the slurry is fed into the higher end. At the lower end is a roaring blast of flame, produced by precisely controlled burning of powdered coal, oil, alternative fuels, or gas under forced draft.

  As the material moves through the kiln, certain elements are driven off in the form of gases. The remaining elements unite to form a new substance called clinker. Clinker comes out of the kiln as grey balls, about the size of marbles. Clinker is discharged red-hot from the lower end of the kiln and generally is brought down to handling temperature in various types of coolers.

  • The heated air from the coolers is returned to the kilns, a process that saves fuel and increases burning efficiency.
  • After the clinker is cooled, cement plants grind it and mix it with small amounts of gypsum and limestone.
  • Cement is so fine that 1 pound of cement contains 150 billion grains.
  • The cement is now ready for transport to ready-mix concrete companies to be used in a variety of construction projects.

  Although the dry process is the most modern and popular way to manufacture cement, some kilns in the United States use a wet process. The two processes are essentially alike except in the wet process, the raw materials are ground with water before being fed into the kiln.

  What are the main constituent of cement?

  Portland cement consists essentially of compounds of lime (calcium oxide, CaO) mixed with silica (silicon dioxide, SiO2) and alumina (aluminium oxide, Al2O3). The lime is obtained from a calcareous (lime-containing) raw material, and the other oxides are derived from an argillaceous (clayey) material.

  What is the percentage of sio2 in OPC?

  While the silicon dioxide is 34.67% which is usually found in lower quantities in OPC, Al 2 O 3 is 11.8% which is higher than the recommended values of 3 -8%, and Fe 2 O 3 content is 6.99% (see Table 1).

  Which is stronger PPC or OPC?

  2.Portland Pozzolana Cement (PPC): – PPC cement is generally used for plastering, brick masonry and waterproofing works. PPC has a lower heat of hydration and it is prone to fewer cracks compared to OPC. PPC has lower strength than OPC but PPC provides better workability and finishing than OPC. PPC provides greater resistance to chemicals.

  Which has more strength OPC or PPC?

  Difference Between OPC and PPC Cement – In the following table is the comparison between OPC vs PPC :

  OPC is made by preparing and then grinding a mixture of limestone and additional raw materials including argillaceous, calcareous, and gypsum.	Pozzolanic components are added to OPC to create PPC. OPC clinker, gypsum, and pozzolanic elements (15–35 %), such as calcined clay, volcanic ash, fly ash, or silica fumes, make up the primary constituents.
  Compared to PPC, initial strength is higher.	Over a lengthier time frame, PPC has more strength than OPC.
  It is less suited for bulk casting because the hydration reaction produces more heat than PPC does.	It produces less heat than OPC because its hydration process is slow.
  less resilient in harsh weather.	less costly than OPC.
  More costly than PPC.	Cheaper than OPC.
  Emits CO2 when it is being manufactured.	It contains both industrial and organic waste, making it environmentally favourable.
  It is suitable for quick construction but unsuitable for bulk concreting due to the heat-related difficulties outlined above.	For all kinds of construction activities, it is appropriate. For instance, mass concrete pouring for bridges, RCC casting of structures, and even plastering and other non-structural activities.
  Inferior to PPC. It takes 30 minutes to set initially, and 280 minutes to set completely. The quicker setting time facilitates quicker building.	PPC requires more time to set than OPC. It takes 30 minutes to set initially, and 600 minutes to set completely. Better finishing is made possible by the slower setting time.
  OPC has 225 sq.m/kg of finiteness. It is less finely ground than PPC. As a result, it is less durable due to its increased permeability.	OPC has a 300 sq.m/kg finiteness. It has a finer texture than OPC. As a result, it is more durable due to its decreased permeability.
  OPC cement is available in grades 33, 43, and 53.	No specified grade of PPC cement is available.
  Lower than PPC.	Superior to OPC.
  It is less resistant to alkalis, sulphates, chlorides, and other substances.	It is more resistant to alkalis, sulphates, chlorides, and other substances.

  Also read –

  What is the strongest gypsum?

  C. High-Strength or Improved Stone – High-strength stone, or improved stone, is also made from gypsum by calcining the gypsum but in a calcium chloride solution. This method of calcination results in a powder particle that is very dense, is cuboidal in shape, and has a reduced surface area.

  1. High-strength stone is the strongest and most expensive of the three gypsum products, and it is used mainly for making casts or dies for crown, bridge, and inlay fabrication.
  2. Figure 9.3 shows an example of an improved stone cast and several dies for the fabrication of crowns.
  3. This material is used because high strength and surface hardness are required during the fabrication process; the fabrication of crowns is described in the next chapter.

  High-strength stone is often referred to as Type IV stone, die stone, densite, or modified alpha-hemihydrate. A newly developed high-strength stone with a higher compressive strength than that of Type IV stone is also available. It displays higher setting expansion and is referred to as Type V stone.

  What is the percentage of calcium sulphate and gypsum in Portland cement?

  Gypsum is added 3% to 4% in ordinary portland cement and reduced by 2.5% in Quick setting cement.

  What are the main composition of cement?

  Visit ShapedbyConcrete.com to learn more about how cement and concrete shape the world around us. Portland cement is the basic ingredient of concrete. Concrete is formed when portland cement creates a paste with water that binds with sand and rock to harden.

  • Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients.
  • Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.

  These ingredients, when heated at high temperatures form a rock-like substance that is ground into the fine powder that we commonly think of as cement. Bricklayer Joseph Aspdin of Leeds, England first made portland cement early in the 19th century by burning powdered limestone and clay in his kitchen stove.

  • With this crude method, he laid the foundation for an industry that annually processes literally mountains of limestone, clay, cement rock, and other materials into a powder so fine it will pass through a sieve capable of holding water.
  • Cement plant laboratories check each step in the manufacture of portland cement by frequent chemical and physical tests.

  The labs also analyze and test the finished product to ensure that it complies with all industry specifications. The most common way to manufacture portland cement is through a dry method. The first step is to quarry the principal raw materials, mainly limestone, clay, and other materials.

  • After quarrying the rock is crushed.
  • This involves several stages.
  • The first crushing reduces the rock to a maximum size of about 6 inches.
  • The rock then goes to secondary crushers or hammer mills for reduction to about 3 inches or smaller.
  • The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed, and fed to a cement kiln.

  The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge cylindrical steel rotary kilns lined with special firebrick. Kilns are frequently as much as 12 feet in diameter—large enough to accommodate an automobile and longer in many instances than the height of a 40-story building.

  • The large kilns are mounted with the axis inclined slightly from the horizontal.
  • The finely ground raw material or the slurry is fed into the higher end.
  • At the lower end is a roaring blast of flame, produced by precisely controlled burning of powdered coal, oil, alternative fuels, or gas under forced draft.

  As the material moves through the kiln, certain elements are driven off in the form of gases. The remaining elements unite to form a new substance called clinker. Clinker comes out of the kiln as grey balls, about the size of marbles. Clinker is discharged red-hot from the lower end of the kiln and generally is brought down to handling temperature in various types of coolers.

  The heated air from the coolers is returned to the kilns, a process that saves fuel and increases burning efficiency. After the clinker is cooled, cement plants grind it and mix it with small amounts of gypsum and limestone. Cement is so fine that 1 pound of cement contains 150 billion grains. The cement is now ready for transport to ready-mix concrete companies to be used in a variety of construction projects.

  Although the dry process is the most modern and popular way to manufacture cement, some kilns in the United States use a wet process. The two processes are essentially alike except in the wet process, the raw materials are ground with water before being fed into the kiln.

  Which is the maximum percentage of Colour Add in Colour cement?

  Free Gujarat Engineering Service 2019 Official Paper (Civil Part 1) 150 Questions 150 Marks 90 Mins Concept- Coloured cement: The cement of desired colour may be obtained by intimately mixing mineral pigments with ordinary cement. The amount of colouring material may vary from 5% to 10%. If the percentage exceeds 10%, the strength of cement is affected.

  Pigment	Colour
  Chromium oxide	Green
  cobalt	blue
  Iron oxide	Brown, red or yellow
  Manganese dioxide	Black or brown

  White cement: The first white cement factory was set up in Kottayam, Kerala by Travancore Cement Limited (TCL) in 1956 and the cement put up for the manufacture of white cement in our country. Thus is just a variety of ordinary cement and it is prepared from such raw materials which are practically free from colouring oxides of iron, manganese or chromium.

  For burning of this cement, the oil fuel is used instead of coal. It is white in colour and it is used for floor finish, plaster work, ornamental work, etc. It should not set earlier than 30 mints. Latest GPSC Engineering Services Updates Last updated on Oct 1, 2022 The Gujarat Public Service Commission (GPSC) has released a new notification for the GPSC Engineering Services Recruitment 2022.

  The commission has released 28 vacancies for the recruitment process. Candidates can apply for the applications from 15th October 2022 to 1st November 2022 and their selection will be based on Prelims, Mains and Interview. Candidates with a Graduation degree as the basic GPSC Engineering Services Eligibility Criteria are eligible to appear for the recruitment process.

  

  Nehru Baral