Basic Civil Engineering Questions and Answers – Ingredients of Cement This set of Basic Civil Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Ingredients of Cement”.1. What is the most dominant constituent of cement? a) Silica b) Lime c) Magnesia d) Alumina View Answer Answer: b Explanation: Cement contains about 60-65% of lime.
2. Deficiency of lime in cement leads to: a) Unsound cement b) Disintegration of cement c) Quick setting of cement d) Expansion of cement View Answer
Answer: c Explanation: Presence of lime in sufficient quantity is necessary to form silicates and aluminates of calcium. Excess lime leads to expansion, disintegration and unsoundness of cement.3. What effect does calcium sulphate have on cement? a) Retards setting action b) Acts as flux c) Imparts colour d) Reduces strength View Answer Answer: a Explanation: Calcium sulphate is found in cement in the form of gypsum.
Its slows down the setting time of cement. Note: Join free Sanfoundry classes at or 4. Which of the following adds a quick-setting property to cement? a) Magnesium oxide b) Silicon dioxide c) Iron oxide d) Aluminium oxide View Answer Answer: d Explanation: Aluminium Oxide or Alumina is present in small quantity in cement and it helps in a quick-setting property.5.
Which of the following imparts greenish grey colour to cement? a) Calcium silicate b) Calcium aluminate c) Calcium aluminate ferrite d) Calcium carbonate View Answer Answer: c Explanation: Calcium silicate and calcium aluminate are pure white minerals.
Calcium aluminate ferrite is brown in colour, but due to absorption of light by magnesium, present as an impurity, greenish grey colour is imparted to cement.6. Excess of Alkali in cement results in: a) Dry cement paste b) Efflorescence c) Less plasticity d) Unsound cement View Answer Answer: b Explanation: Efflorescence is the formation of powdery substance on the surface of masonry or concrete work.
Alkalis usually get carried away by flue gases during heating. In excess quantity, they result in alkali-aggregate reaction.7. What function does iron oxide perform in cement? a) Increases strength b) Makes cement sound c) Increases setting time d) Acts as flux View Answer Answer: d Explanation: Iron oxide acts as a flux, in addition to being responsible for imparting colour to cement.
If the temperature goes higher, then iron oxide reacts with aluminium and calcium and results in the formation of calcium aluminate ferrite.8. How many major ingredients are present in the composition of cement? a) 8 b) 5 c) 10 d) 6 View Answer Answer: a Explanation: There are 8 main ingredients present in cement.
They are lime, silica, alumina, magnesia, iron oxide, calcium sulphate, sulphur trioxide and alkalis.9. Sulphur in cement is present in what amount? a) 0.5 – 6 g b) 1 – 2.5% c) 0.5 – 6% d) 1 – 2.5g View Answer Answer: b Explanation: The presence of ingredients is expressed in percentage.
- Iron oxide is present in 0.5-6% and sulphur 1-2.5%.10.
- An excess of magnesium oxide after 5% is harmful to cement.
- A) True b) False View Answer Answer: a Explanation: Excess of magnesium causes problems in structures built with this cement.
- It causes cracks in both mortar and concrete after they harden.
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- 0.1 Why is gypsum used in cement?
- 0.2 What is the chemical properties of cement?
- 0.3 How do you make grey cement white?
- 0.4 What colour is Portland cement?
- 0.5 What are the uses of grey cement?
- 0.6 How do you colour cement?
- 0.7 What makes cement red?
- 1 How do they color concrete?
Which of the following cement is are made of grey or white?
The grey cement is the more commonly used cement everywhere, whereas the white cement is used for specific purposes only, or when a certain kind of finish is required.
Why is gypsum 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%.
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What is the role of Aluminium oxide in cement?
Abstract – The use of nanomaterials has become a popular way to improve the performance of cement-based composites. At the same time, ultra-high strength concrete is becoming more widely used. These materials provide superior durability to infrastructure elements, reducing the need for maintenance or early replacement.
- The performance boost is achieved by producing a denser microstructure and, in the case when nanofibers are used, may reduce the initiation of cracks.
- Aluminum oxide nanomaterials have the potential to provide a significant increase in compressive strength of cement-based materials.
- Here, the effect of incorporation of aluminum oxide nanofibers in oil well cement based mortars and composites is reported.
The design of ultra-high strength concrete often requires a precisely tuned aggregate gradation, the use of specific cement types and high quantities of silica fume and superplasticizers along with high temperature and curing under elevated pressure.
- It was demonstrated that the use of small quantities of aluminum oxide nanofibers in an oil well cement based mortar could provide a compressive strength approaching 200 MPa.
- These levels were achieved at a considerably lower dosage of silica fume.
- It is envisioned that the high strength matrix is formed due to the reinforcing of calcium silicate hydrate layers which are formed around the nanofibers.
This research demonstrated that due to a “shish kebab” effect the addition of well-dispersed aluminum oxide nanofibers at a very small dosage of 0.25% (by mass of cement) could provide up to 30% increase in compressive strength of cementitious systems, helping to meet the benchmarks for ultra-high strength cement-based composites.
What is the chemical properties of cement?
(b) Chemical Properties of Cement
|Sr No.||Oxide||Composition in % (Content percentage)|
What is the properties of cement?
Cement is one of the most popular building material, It is used as a binder in the construction industry. It has both adhesion and cohesion properties. It can bind particles into a compact durable solid mass. Cement has a wide application in the construction industry such as:
- When cement is mixed with sand and water to form a paste, it is termed as mortar. The mortar is used to join bricks or stones and in finishing works such as plastering and pointing.
- When cement is mixed with gravel (or crushed stones), sand and water, the composite product is called concrete. The concrete is the second most used material on this planet. It is used for constructing footings, beams, columns, slabs, stairs, etc.
There are many types of cement which are used as per their requirements and properties
How do you make grey cement white?
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If you add our Direct Colors to a white concrete mix, you can create brilliant white concrete countertops. If you’re building a concrete countertop from scratch, use a high-quality white c oncrete countertop mix that contains white Portland cement, chopped fiberglass (for reinforcement), and white sand.
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Simply apply a to your old countertop for a clean white finish. Before After pearl white concrete overlay by Liz Morrow Studios Skimcoat of Direct Colors Pearl White Smooth Concrete Overlay Skim coat of Direct Colors Smooth Pearl White Concrete Overlay Check out the complete project by Liz Morrow Studios of Tacoma Interior Design on her blog,
Pearl White No. A true white color can only be achieved using a white cement mix. Add white to a gray concrete mix to create a sleek “ash” look that’s popular in modern homes. Ash concrete overlay over laminate bathroom countertop For a true white finish, remember to use white concrete p igment with white concrete countertop mix or concrete overlay. Kitchen Island built with white concrete pigment and white countertop mix If you want a solid white look, the fastest and least expensive option is to apply a hite concrete stain Another way to add a fabulous white color to gray concrete is by using a earl metallic epoxy sealer,
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Which compound gives the colour to the cement Mcq?
Concrete Technology Questions and Answers – Types of Cement This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Types of Cement”.1. Which chemical compostion has highest content in OPC? a) Alumina b) Silica c) Lime d) Iron Oxide View Answer Answer: c Explanation: Lime forms nearly two-third (2/3) of the cement.
2. Excess in lime causes _ a) The cement to shrink and integrate b) The cement to shrink and disintegrate c) The cement to expand and integrate d) The cement to expand and disintegrate View Answer
Answer: d Explanation: Sufficient quantity of lime forms di-calcium silicate (C2SiO2) and tri-calcium silicate in the manufacturing of cement.3. Silica in excess causes _ a) The cement to set slowly b) The cement to set quickly c) The cement to expand d) The cement to disintegrate View Answer Answer: a Explanation: Silica gives strength to the cement.
Silica in excess causes the cement to set slowly.4. Alumina in excess causes _ a) Reduces the strength of the cement b) Inceases the strength of the cement c) No change d) Sometimes increase or decrease the strength of the cement View Answer Answer: a Explanation: Alumina supports to set quickly to the cement.
It also lowers the clinkering temperature. Alumina in excess reduces the strength of the cement.5. Which compound gives the colour to the cement? a) Lime b) Silica c) Iron Oxide d) Alumina View Answer Answer: c Explanation: Iron oxide pigments are in the form of particles ranging approximately from 0.1 to 1.0 micron.
- The difference in color between one pigment and another is due to the shape and surface structure of the particle.
- Check this: | 6.
- Which cement contains high percentage of C 3 S and less percentage of C 2 S? a) Rapid Hardening Cement b) Ordinary Portland Cement c) Quick Setting Cement d) Low Heat Cement View Answer Answer: a Explanation: This cement contains high percentage of C 3 S and less percentage of C 3 S.
This is infact high early strength cement.7. When concrete is to be laid under water _ is to used. a) Rapid Hardening Cement b) Ordinary Portland Cement c) Quick Setting Cement d) Low Heat Cement View Answer Answer: c Explanation: When concrete is to be laid under water, quick setting cement is to used.
- This cement is manufactured by adding small percentage of aluminum sulphate (Al 2 SO 4 ) which accelerates the setting action.8.
- Which of the following is correct for Low Heat Cement? a) Suitable for use in cold weather areas b) Heat of hydration is reduced by tri calcium aluminate content c) This cement requires longer period of curing d) This cement contains high aluminate %age usually between 35-55%.
View Answer Answer: b Explanation: In this cement the heat of hydration is reduced by tri calcium aluminate content. It contains less percentage of lime than ordinary port land cement. It is used for mass concrete works such as dams etc. Sanfoundry Global Education & Learning Series – Concrete Technology.
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What colour is Portland cement?
This article is about the building product of cement. For the Australian heritage-listed production site, see Portland Cement Works Precinct, Bags of portland cement wrapped and stacked on a pallet. Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout, It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone,
- It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum,
- Several types of portland cement are available.
- The most common, called ordinary portland cement (OPC), is grey, but white Portland cement is also available.
Its name is derived from its resemblance to Portland stone which was quarried on the Isle of Portland in Dorset, England. It was named by Joseph Aspdin who obtained a patent for it in 1824. His son William Aspdin is regarded as the inventor of “modern” portland cement due to his developments in the 1840s.
What are the uses of grey cement?
Cement. Dingo General Purpose Cement can be used in a wide range of mortar, concrete and grout applications. It is suitable for bricklaying, rendering, paving and general building.
How do you colour cement?
How to Colour Concrete – There are two main ways to colour concrete.
- The first uses a dry pigment that is brushed across concrete once it has been laid.
- The second uses liquid or dry pigment that is mixed into the concrete before it is poured.
This is possible because the pigment particles are much smaller than cement particles so when they are added to a cement based mix the small particles cover the cement particles and colour them. In both cases iron oxide pigments that have been manufactured or that have been mined from the ground are used.
- For example the sweep over with dry pigment is easy to do, but the resultant concrete can be easily chipped and the dye is less durable.
- The second, combined method, is a little more difficult to do, but if your project is small, or you want to ensure the best results, then choosing it is likely the best solution.
If you would like some help choosing which method to use, take a look at this comparison chart from the concrete network which compares concrete colouring products: For some more tips to help you choose the right colouring method for your coloured concrete task take a look at this link here,
What makes cement red?
Color Pigments used in the Cement Industry – Color Pigments are used in the cement to ensure a long lasting cement color shade. But for this, the pigment must have a good quality. These pigments (color) are made from both natural and synthetic iron oxide, cobalt, titanium dioxide and chromium oxide.
- From iron oxide pigments, red, black and yellow color can be obtained.
- From cobalt pigments, blue color can be obtained.
- White color and green color can be obtained from titanium dioxide and chromium oxide respectively.
- Other colors like buffs, brown, tans, coppers, oranges, chocolates and many other colors can be obtained from the blends of the red, black and yellow colored iron oxide pigments.
These colored pigments are: water- wetable, lightfast, alkali resistant and will not negatively effect the firmness and strength of the cement. But, one thing should we remember about the concentration of these pigments in the cement. This concentration should be within the range of 10% of the weight of the cementitious ingredients.
How do they color concrete?
How Is Concrete Colored? – Colored concrete is made using pigments mined from the ground or manufactured in chemical plants. These pigments come in three different forms: powder, liquid, and granular. Each of these different pigment forms have their own advantages and are used universally.
These colored pigments are made of iron oxide particles that are 10 times smaller than the particles that make up cement. When pigment is combined with wet cement mix, the smaller colored particles surround and cover up the cements’ larger particles, creating a colored tint. The ratio of color pigment is based on the amount of cement mixture used, so the more cement mix involved, the more pigment needed for a darker, bolder color.
More pigment is needed when dying gray concrete. This creates darker, earth tone colors. If you want lighter colors, you will have to use white concrete, which is more costly. If you already have existing gray concrete, you can color it with either a water-based stain or an acid chemical stain.