Building Material (GENERAL ENGINEERING) (SSC JE)

Total Questions: 50

1. The maximum working temperature of Nickel chromium is about: [NHPC JE (ME) 06.04.2022 (Shift-II)]

Correct Answer: (a) 1150°C
Solution:The maximum working temperature of Nickel chromium is about 1150°C, melting point 1400°C, specific gravity 8.4 gm/cm3 and high resistance to oxidation.

2. Which of the following is NOT a grade of cement as per IS classification ? [NHPC JE (Civil) 04.04.2022 (Shift-II)]

Correct Answer: (a) Ordinary Portland cement (OPC) 23
Solution:Classification of cement–

1. 33 grade OPC; IS-269 of 1989

2. 43 grade OPC; IS-8112 of 1989

3. 53 grade OPC; IS-12269 of 1987

3. According to IS 2222 (1991): 'Specification for burnt clay perforated building bricks', the area of each perforated in the perforated bricks shall not exceed________cm2 . [JSSC JE (GEN. ENGG.) 04.11.2022]

Correct Answer: (d) 5.00
Solution:Specification for perforated burnt clay building bricks (IS 2222-1991)

• Bricks shall be free from cracks and flows and nodules of free lime.

• Bricks shall be of uniform in colour and texture.

• The area of perforation shall be in between 30% to 45% of the total area of the corresponding face of the bricks.

• The shorter side of the perforation shall be less than 20 mm in case of rectangular perforation and less than 25 mm diameter in case of circular perforations.

• Area of each perforation shall not exceed 500 mm2 or 5 cm2

• Thickness of any shell shall not be less than 15 mm and that of any web not less than 10 mm

• Average compressive strength shall not be less than 7 N/mm2 on net area

• Water absorption shall not be more than 20% by weight

• Average warpage shall not exceed 3%.

4. According to Indian standards, what is the safe bearing capacity of rocks without laminations and defects useful for laying foundation? [JSSC JE (GEN. ENGG.) 04.11.2022 ]

Correct Answer: (a) 330 t/m²
Solution:Recommended values of safe bearing capacity for preliminary analysis
Sl. No.Type of Rock or SoilSafe Bearing Capacity (kN/m²)Safe Bearing Capacity (kg/cm²)
1Rocks (hard) without lamination and defects, for example granite, trap and diorite330033
2Laminated rocks, for example sandstone and limestone in sound condition165016.5
3Residual deposits of shattered and broken bed rock and hard shale, cement material9009
4Soft rock4504.5
Sl. No.Type of SoilSafe Bearing Capacity (kN/m²)Safe Bearing Capacity (kg/cm²)
5Gravel, sand and gravel mixture compact and offering high resistance to penetration when excavated by tools4504.5
6Coarse sand, compact and dry (with ground water level at a depth greater than width of foundation below the base of footing)4504.5
7Medium sand, compact and dry2502.5
8Fine sand, silt (dry lumps easily pulverized by fingers)1501.5
9Fine sand, loose and dry1001.0

5. Which of the following is used as an organic solvent preservative in the process of preservation of timber? [JSSC JE (GEN. ENGG.) 04.11.2022 ]

Correct Answer: (b) Copper naphthenate
Solution: Preservation of timber–In order to protect the timber from attacks of insects, chemical preservative are used to increase the life of the wood.

Types of preservatives–

Tar oils–It is used to rough types of work. Creasote is most commonly used and various creasotes are cool tar, wood tar and water gas etc.

Water soluble preservatives (chemical salts)– These are odourless organic or inorganic salts and are adopted for inside location only this type of preservative are zinc chloride, boric acid, sodium fluoride etc.

Organic solvent preservatives– There are costlier than other preservatives. The common used organic solvent preservatives are nepthal and phenol (DDT) etc.

6. What should be the penetrating power of a good timber preservative? [JSSC JE (GEN. ENGG.)- 31.10.2022]

Correct Answer: (b) 6 mm to 25 mm
Solution: Properties of good preservative for timber–

• It should be effortlessly and cheaply available.

• It should not contain any harmful substances, gases etc.

• It should be economical.

• Decorative treatment should be allowed on timber after the application of preservative.

• It should not contain any unpleasant smell.

• It should not generate flame when contacts with fire.

• The depth of penetration of preservative in wood fibers should be minimum 6 mm to 25 mm.

7. How many days does it take for Rapid Hardening Cement to develop the same strength as that is expected of Ordinary Portland Cement at 7 days? [JSSC JE (GEN. ENGG.)- 31.10.2022]

Correct Answer: (c) 3
Solution:Rapid Hardening Cement (IS 8041-1990) This cement is similar to ordinary portland cement. It develops strength rapidly and as such it may be more appropriate to call it as high early strength cement. Rapid hardening cement develops at the age of 3 days the same strength so that is expected of OPC at 7 days. The rapid rate of development of strength is attributed to the higher fineness of grinding and higher C₃S and lower C₂S content.

The use of rapid hardening cement is recommended in the following situations–

• In pre-fabricated concrete construction

• Road repair works

• In cold weather concrete where the rapid rate of development of strength reduces the vulnerability of concrete to the frost damage.

8. What is the purpose of using vehicle components in paint manufacturing? [JSSC JE (GEN. ENGG.)- 31.10.2022 ]

Correct Answer: (c) To spread the paint evenly
Solution:Vehicle

It is also known as binder. Vehicle is an oil to which the base is mixed. It holds the constituents of paint in suspension and helps spread it over the surface to be painted, imparts durability, toughness and water proofness to the paint film and resistance to weathering and gloss to the painted surface and forms the body of paint.

The purpose of using vehicle is components in paint manufacturing to spread the paint evenly

9. The type of aggregate surface texture characteristics carried by Pumice and trass is : [JSSC JE (GEN. ENGG.)-23.10.2022 ]

Correct Answer: (c) honeycombed and porous
Solution:Surface texture characteristics of the aggregate as classified in IS: 383-2016 is shown below
GroupSurface TextureExamples
1.GlassyBlack flint
2.SmoothChert, slate, marble, some rhyolite
3.GranularSandstone, oolites
4.CrystallineFine: Basalt, trachyte Medium: Dolerite, granophyres, granulites, micro-granite, some limestones, many dolomites Coarse: Gabbro, gneiss, granite, granodiorite, syenite
5.Honeycombed and porousScoria, pumice, trass

10. White cement manufacturing needs higher firing temperature up to : [JSSC JE (GEN. ENGG.)-23.10.2022 ]

Correct Answer: (a) 1650°C
Solution:White cement (IS 8042) – It is manufactured from pure white chalk and clay free from iron oxide, grayish colour of cement is due to iron oxide.

• Loss on ignition of white cement is nil.

• The compressive and transverse strength of this cement is 90% of that of 33 grade ordinary Portland cement.