Civil Engineering Questions and Answers

Civil Engineering Question 1

 In a mortar, the binding material is-

1. Cement
2. Sand
3. Surkhi
4. Cinder

Answer: A. Cement

Solution

Cement, sand, aggregate, and water are the ingredients of mortar which can be present in a variety of ratios. In all those aggregates, the minimum setting time for cement is 30 minutes. Therefore, cement serves as the binding component in mortar.

Mortar: It refers to a paste made by adding the necessary amount of water to a blend of binding material, such as cement or lime, and fine aggregate, such as sand.

• The binding substance known as the matrix and fine aggregate as an adulterant are the two aforesaid components of mortar.
• The matrix holds the adulterant particles together, hence the quantity, quality, and strength of the mortar will largely depend on these factors.
• The two parts of mortar work together to give the mass the ability to tightly bind the bricks or stones.

Civil Engineering Question 2

Lacquer paints-

1. Are generally applied on structural steel
2. Are less durable as compared to enamel paints
3. Consist of resin and nitro-cellulose
4. All of the above

Answer: D. All of the above

Solution

In order to prevent corrosion, lacquer paint is typically used on steel or casting equipment and it is more durable than enamel paint. This paint is used in the automotive industry for engine casing. To protect and shine up wood or metal, lacquer is a liquid that is applied on the surface. When applied to wood or metal, it is a liquid that resembles varnish and dries quickly to form a lustrous covering.

Nitrocellulose, plasticizers, and pigments are all dissolved in a mixture of volatile solvents to create lacquer, a type of product with a solvent base. Additionally, shellac in alcohol is dissolved in lacquer to produce a synthetic coating and high gloss surface. The word “lacquer” comes from the Portuguese word “lac,” which refers to a type of resin secreted by some insects.

Civil Engineering Question 3

Wrought iron contains carbon upto-

1. 0.25 %
2. 1.0 %
3. 1.5 %
4. 2.0 %

Answer: A. 0.25%

Solution

Wrought iron is a very pure form of iron with an iron concentration of around 99.5 percent. It typically has a slag content of 1%–2% and less than 0.1 percent carbon.

• It is made by remelting pig iron, and silicon, sulphur, or phosphorus may be present in trace amounts.
• It is ductile, robust, malleable, and easily forged or welded.
• However, it cannot withstand a rapid shock. This iron can be used to make chains, crane hooks, railway couplings, and other parts.

Pig iron: An intermediate product of the iron industry is called pig iron. Pig iron is exceedingly brittle and not used directly as a material, with a normal carbon percentage of 3.8 – 4.7%. This high carbon content, combined with silica and other dross components, also makes it very brittle.

Cast iron is a brittle, hard alloy containing iron, carbon, and silicon. Cl may include 1.7% to 3%  of carbon, and that carbon may be in the form of free carbon or iron carbide, Fe₃C. Cast iron comes in a variety of forms, such as (a) grey cast iron, (b) white cast iron, (c) malleable cast iron, etc.

Steel is essentially an alloy of iron and carbon, with a carbon percentage that can be as low as 1.7%. To provide hardness and strength, carbon is added in the form of iron carbide. There are two primary types of steel: alloy steel and plain carbon steel.

Thus, contrary to cast iron, wrought iron is an iron alloy with a very low carbon content (less than 0.08 percent).

Civil Engineering Question 4

Pick up the polymineralic rock from the following:

1. Quartz sand
2. Pure gypsum
3. Magnesite
4. Granite

Answer: D. Granite

Solution

Polymineralic refers to the presence of more than one mineral. Minerals including feldspar, quartz, mica, and amphibole make up the majority of these rocks.

Composition of granite:

SiO₂ 72.04% (silica)

Al₂O₃ 14.42% (alumina)

K₂O₄  4.12%

Na₂O₃ 3.69%

CaO 1.82%

FeO 1.68%

Fe₂O₃ 1.22%

MgO 0.71%

TiO₂ 0.30%

P₂O₅ 0.12%

MnO 0.05%

Civil Engineering Question 5

Pick up the correct statement from the following:

1. For thin structures subjected to wetting and drying, the water-cement ratio should be 0.45.
2. For mass concrete structures subjected to wetting and drying, the water ratio should be 0.55.
3. For thin structures which remain continuously underwater, the water-cement ratio by weight should be 0.55.
4. All of the above.

Answer: D. All of the above

Solution

Exposure	Plain Concrete			Reinforced Concrete
	Minimum cement content kg/m3	Maximum free water-cement ratio	Minimum grade of concrete	Minimum cement content kg/m3	Maximum free water-cement ratio	Minimum grade of concrete
Mild	220	0.60	–	300	0.55	M20
Moderate	240	0.60	M15	300	0.50	M25
Severe	250	0.50	M20	320	0.45	M30
Very severe	260	0.45	M20	340	0.45	M35
Extreme	280	0.40	M25	360	0.40	M40

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