Aluminium Oxide Which of the following adds a quick-setting property to cement? Explanation: Aluminium Oxide or Alumina is present in small quantity in cement and it helps in a quick-setting property.

Which of the following imparts quick setting of cement?

Silica is responsible for strength of cement, alumina imparts quick setting property, Calcium Sulphate delays setting of cement, Magnesium Oxide in large quantity-causes delayed expansion.

Which of the following ions causes the cement to set quickly?

Basic Civil Engineering Questions and Answers – Source and Classification of Lime This set of Basic Civil Engineering Multiple Choice Questions & Answers focuses on “Source and Classification of Lime”.1. By which of the following ways is lime obtained? a) Naturally b) Quarrying c) Burning limestone d) Crushing limestone View Answer Answer: c Explanation: It is not available naturally.

1. It is obtained by burning limestone, shells of sea animals and boulders of limestone from old river beds.2.
2. Which of the following pairs is matched properly? a) Class A – Concrete work b) Class B – Mortar c) Class C – Masonry work d) Class D – White washing View Answer Answer: b Explanation: Based on percentage of CaCO 3 in limestone, lime is classified into 3 – Class A, B & C.Class A is used for masonry work, Class C is used for white washing and there is no class D.3.

Lime has been conventionally classified into how many types? a) 4 b) 2 c) 5 d) 3 View Answer Answer: d Explanation: The three conventional classifications of lime are, Fat Lime, Hydraulic Lime and Poor Lime.4. Which of the following is a property of Fat Lime? a) Shakes very slowly b) Contains clay c) High degree of plasticity d) Poor binding property View Answer Answer: c Explanation: Fat Lime is pure lime.

The rest of the 3 options describe properties of poor lime.5. Lime obtained from calcination of Pure Limestone is called: a) Quick Lime b) Pure Lime c) Lean Lime d) Rich Lime View Answer Answer: a Explanation: Quick lime is pure limestone product. It consists of oxides of calcium and is not crystalline.

Pure Lime and Rich Lime are different names of Fat Lime. Lean Lime is also another name of Poor Lime. Check this: 6. What is the speciality of Hydraulic Lime? a) Contains impurities b) Does not set under water c) Contains clay d) Perfectly white in colour View Answer Answer: c Explanation: The clay content gives it the hydraulic property – capacity to set and harden even under water.7.

Which of the following slakes after few minutes? a) Moderately Hydraulic Lime b) Eminently Hydraulic Lime c) Perfectly Hydraulic Lime d) Feebly Hydraulic Lime View Answer Answer: d Explanation: Hydraulic Lime slakes at a slower rate than Pure Lime. It is subdivided into three – Feebly Hydraulic, Moderately Hydraulic (1-2 hrs) and Eminently Hydraulic (slakes with difficulty).8.

Which of the following types of Lime does not exist? a) Dolomitic Lime b) Roman Lime c) Semi-Hydraulic Lime d) Selentic Lime View Answer Answer: b Explanation: Semi-Hydraulic Lime contains lesser clay content than Hydraulic Lime. Dolomitic Lime comprises of high magnesium carbonate (35-46%) content.

Selentic Lime is cement of grey chalk, with added gypsum. Roman Lime does not exist, instead there is Roman Concrete which is obtained by mixing lime and volcanic ash.9. Which of the following ions causes the cement to set quickly? a) Sulphate b) Carbonate c) Chloride d) Nitrate View Answer Answer: a Explanation: Sulphate arrests slaking and hence cement can set quickly and become stronger.10.

Lime is widely used for: a) Waste water treatment b) Manufacturing tiles c) Jewellery making d) As an aggregate View Answer Answer: a Explanation: Hydrated Lime is a highly efficient pH increasing agent. It is used as a primary coagulant for waste water treatment and contributes to the clarity of the water.

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Which of the following important ingredients of cement increases the setting time of cement?

Calcium Sulphate (CaSO4) is in the form of Gypsum and its function is to increase the initial setting time of cement.

Which one of the following compounds is responsible for quick setting of cement Mcq?

Discussion :: Building Materials – Section 3 ( Q.No.2 ) –

PRITHVI said: (May 30, 2014)
Early gain of strength is caused due to tricalcium silicate and thus setting time too.

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Vikas said: (Feb 19, 2016) Tricalcium silicate responsible for early setting of cement.

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Sonu said: (Jul 29, 2016) Answer is wrong C3S (Tricalcium Silicate) is responsible for initial setting and Di Calcium silicate (c2s) contributes strength after 7 days.

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Sohan Jangra said: (Sep 29, 2016) Answer is right, When water is mixed with cement to form a paste, reaction starts. In its pure form, the finely ground cement is extremely sensitive to water. Out of the three main compounds, viz. C3A, C3S, and C2S, reacts quickly with water to produce a jelly-like compound which starts solidifying. The action of changing from a fluid state to a solid state is called ‘setting’ and should not be confused with ‘hardening’.

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Devaraj said: (Dec 31, 2016) Silica indicates strength aluminium indicates settings times.

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Laxman Prasad said: (Mar 8, 2017) How long time due to tri-calcium aluminate gains the initial setting by cement?

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Chandrima said: (Apr 22, 2017) I think it is Tri calcium silicate.

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Amitkumarsachin said: (Jul 1, 2017) C3S is responsible to early strength not early setting time, C3A is responsiblefor early setting time.

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Ramavtar said: (Dec 13, 2017) C3S is correct.

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Shekhar Kumar said: (Jan 27, 2018) Properties of cement compounds These compounds contribute to the properties of cement in different ways Tricalcium silicate, C3S:- This compound hydrates and hardens rapidly. It is largely responsible for portland cement’s initial set and early strength gain. Dicalcium silicate, C2S:- C2S hydrates and hardens slowly. It is largely responsible for strength gain after one week. Tricalcium aluminate, C3A:- It liberates a lot of heat during the early stages of hydration, but has little strength contribution. Gypsum slows down the hydration rate of C3A. Cement low in C3A is sulphate resistant. Tetracalcium alumino Ferrite, C4AF:- This is a fluxing agent which reduces the melting temperature of the raw materials in the kiln (from 1650o C to 1450o C). It hydrates rapidly but does not contribute much to the strength of the cement paste. By mixing these compounds appropriately, manufacturers can produce different types of cement to suit several construction environments.

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Rabindra said: (Apr 10, 2018) The Answer is right because it is asking the for the early setting time of cement which is due to tricalcium aluminate but for the early strength of cement, tricalcium silicate and ultimate strength or final strength is due to dicalcium silicate. So don’t be confused be clear.

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Basavaraj said: (Aug 21, 2018) C3S for initial setting. C3A for the flash setting. C2s for Ultimate strength.

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ABHISHEK YADGIRI MUDIRAJ said: (Sep 19, 2018) C3S and C2S for strength and C3A for the early setting of cement.

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Sunil Kumawat said: (Oct 31, 2018) C3A is responsible for both flash and initial setting time.

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Muttu said: (Apr 29, 2019) Option A is the correct answer.

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OPSC AEE said: (Oct 29, 2019) Give ans is right. Here asked about initial setting, not asked speeds the setting. Kindly read the que again.

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Aditya said: (Jan 30, 2020) The setting and hardenings of cement paste is mainly due to the hydration and hydrolysis.

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Dharanidharan said: (Feb 21, 2020) Answer C is correct. Be because. C3s strenth property. C3a time &hydration property.

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Nitesh said: (Mar 9, 2020) Hello guys, the answer is right, because C2S is responsible for early STRENGTH of cement in the INITIAL stage, in this question ask the initial setting time of cement.

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Joey said: (Jun 15, 2020) C3S – early strength. C2S – ultimate strength. C3A – the initial setting of cement. Heat of hydration C3A > C3S > C4AF > C2S.

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Sushant Kumar Sahu said: (Jul 29, 2020) When water is added in cement, first tricalcium aluminate is reacted with water and it is responsible for initial setting of cement.

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Priyanka said: (Apr 2, 2021) Early strength – C3S. Early setting – C3A.

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Black Lover said: (May 19, 2021) I think option A is correct.

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Him said: (Aug 7, 2021) I’m agree with you, Thanks @Joey.

Civil Engineering – Building Materials – Discussion

Which chemical is used to setting of concrete?

2. Accelerating admixtures – Accelerators shorten the set time of concrete, allowing a cold-weather pour, early removal of forms, early surface finishing, and in some cases, early load application. Proper care must be taken while choosing the type and proportion of accelerators, as under most conditions, commonly used accelerators cause an increase in the drying shrinkage of concrete.

Calcium chloride is a common accelerator, used to accelerate the time of set and the rate of strength gain. It should meet the requirements of ASTM D 98. Excessive amounts of calcium chloride in concrete mix may result in rapid stiffening, increase in drying shrinkage and corrosion of reinforcement. In colder climates, calcium chloride should not be used as an anti-freeze.

Large amount of calcium chloride is required to lower the freezing point of the concrete, which may ruin the concrete.

Which compound is used to increase setting time in cement?

Gypsum is used to increase the initial setting time of cement. Gypsum is a retarder and prevents flash set. Cement manufacturing requires about 2 to 3% of Gypsum.

Why gypsum is used in cement?

(2) The Mixing Amount of Gypsum – Gypsum is called the retarding agent of cement which is mainly used for regulating the setting time of cement and is an indispensable component. Without gypsum, cement clinker can condense immediately by mixing with water and release heat.

The major reason is that C 3 A in the clinker can dissolve in water quickly to generate a kind of calcium aluminate hydrate, a coagulant agent, which will destroy the normal use of cement, the retardation mechanism of gypsum is: when cement is hydrated, gypsum reacts with C 3 A quickly to generate calcium sulfoaluminate hydrate (ettringite) which deposits and forms a protection film on the cement particles to hinder the hydration of C 3 A and delay the setting time of cement.

If the content of gypsum is too little, the retardation affect will be unobvious. Too much gypsum will accelerate the setting of cement because gypsum can generate a coagulating agent itself. The appropriate amount of gypsum depends on the content of C 3 A in the cement and that of SO 3 in gypsum, and it also related to the fineness of cement and the content of SO 3 in clinker.

The amount of gypsum should account for 3% ~ 5% of the cement’s mass. If the content of gypsum exceeds the limit, it will lower the strength of cement and it can even lead to poor dimensional stability, which will cause the expanded destruction of cement paste. Thus, the national standard requires that the content of SO 3 should not be more than 3.5%.

Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9781845699550500049

What is the role of Aluminium sulphate in cement?

THE APPLICATION SCOPE / PURPOSE Aluminum sulfate is a typical additive in the production of cement for the construction industry. Aluminum sulfates are used to increase the viscosity of the concrete mass, to prevent sediment deposition and to prevent dripping from the wall.

Which of the following cement is used when concrete is to be laid underwater Mcq?

Pozzolana cement is used for underwater construction.

How does quick setting cement work?

Ingredient Quick Setting Cement? – Quick Setting Cement Quick setting cement is a special type of cement, where the setting time of hardening of cement to be fast and the cement is to be less. The cement clinkers are grinded with aluminum sulfate, which accelerates the setting time of cement.

1. Aluminum sulfate is used as an accelerating admixture in the dosage range of 1% to 3% by weight of cement clinkers.
2. The mechanism of function of aluminum sulfate is that it raises the rate of hydration of tricalcium silicate (C3S) & tricalcium aluminate (C3A) phases of cement, thus providing sooner heat evolution and strength development.

It is acts as a catalyst in the hydration of tricalcium silicate (C3S) and tricalcium aluminate (C3A). Concrete specimens with varying percentages of aluminum sulfate were tested for compressive strength, splitting tensile strength, and flexural strength.

Which of the following is added to cement to reduce the setting time of cement?

Setting time of cement decreases by adding Calcium Chloride.

What is a quick setting cement?

Abstract Quick Setting Cement (QSC) is a special cement formulation which rapidly develops compressive strength and significantly reduces waiting on cement (WOC) time compared to conventional cement systems. The description of the cement properties and case histories are given.

• The case histories show the advantages of QSC system for use in the following situations.
• On lost circulation zones encountered while drilling.
• To stabilize unconsolidated ground when drilling throughfills associated with strip mining.
• For lower drilling costs when open mines are encountered by reducing the WOC time when an additional string of casing has to be set.

* To shut off large water flows that would otherwiseprohibit further drilling. Introduction The majority of wells in the Appalachian Basin are drilled on air. One reason is that certain formations are not competent enough to support a column of drilling mud.

1. On occasion, zones are encountered where circulation with air is not obtainable, or due to hole conditions, the drilling rate is substantially reduced.
2. These problems are generally encountered at shallow depths when drilling a well.
3. Many of the problems are due to the presence of coal mines in the area.

Both underground and surface presence of coal mines in the area. Both underground and surface mining have been active for many years and continue. In areas of surface mining, large fills are often created. These fills are areas where valleys or depressions have been filled with the residue from the mining process.

1. The material in these fills may range in size from silt size particles to boulders.
2. This is all unconsolidated and varies in thickness from a few feet to hundreds of feet.
3. Drilling surface hole for conductor pipe can be difficult in this unconsolidate ground.
4. The result may be very large wash outs and loss of circulation.

The use of cement plugs to stabilize the ground and to plug lost circulation zones is a common practice. In areas of underground mining, operators will try to avoid drilling through an open mine. An open mine is a section that has been mined through, but has not been backfilled.

1. In these areas, operators generally set a conductor pipe that is large enough to allow for a mine string in the casing program.
2. The mine string is an extra string of casing set through the mine.
3. When an open mine is encountered, circulation of cuttings to the surface is lost.
4. The rig must then drill approximately 30 feet (9.1m) through the floor of the mine before casing is run.

When this casing is cemented, enough cement is pumped down the casing to set a balanced plug in the casing and annulus up to the mine floor. A cement basket is placed on the casing above the top of the mine which allows the annulus above the mine to be grouted back to surface.

Large water flows are occasionally encountered when drilling with air. This is due to the lack of hydrostatic pressure on the annulus to control the influx of water. If the rig air capacity is not adequate to keep the water circulated out of the hole, the rate of penetration will decrease and the condition of the hole will penetration will decrease and the condition of the hole will deteriorate.

Even if circulation can be maintained the problems of pit capacity and water disposal have to be addressed. The water pit capacity and water disposal have to be addressed. The water zone may have to be shut off to avoid having to run an additional string of casing.

What makes fast setting concrete set fast?

How is rapid-set concrete made? – There are three base ingredients in any concrete mix: water, cement and aggregates. You can change the characteristics of a mix by changing the proportions of each ingredient. Rapid-set concrete has a higher cement content than standard mixes, and will also contain specific admixtures to speed up the hydration process.