Building Material (GENERAL ENGINEERING) (SSC JE)

Total Questions: 50

21. What is the approx thickness of two and half brick wall made up of standard modular brick? [JSSC JE (GEN. ENGG.)- 03.07.2022 ]

Correct Answer: (b) 19.685 inch
Solution:Standard size of brick = 19 cm × 19 cm × 9 cm.

Nominal size of brick with mortar = 20 cm × 10 cm × 10 cm

Non-modular brick

Conventional size of brick = 22.4 cm × 11.4 cm × 7.6 cm

Wall thickness = Thickness of modular brick + Mortar thickness

22. The argillaceous rock has their principal constituents as [JSSC JE (GEN. ENGG.)- 03.07.2022]

Correct Answer: (b) Clay or Alumina
Solution:The argillaceous rock has their principal constituents as clay or alumina.

Example–Granite, Gneiss, Trap, Basalt, Sand stem.

23. Which of the following will you recommend for painting internal wall? [JSSC JE (GEN. ENGG.)- 03.07.2022]

Correct Answer: (c) Emulsion
Solution:Emulsion paints– Two types of emulsion paints are available, one is ordinary emulsion and the other is plastic emulsion.

• The emulsion paint is easy to apply and dries quickly

within 3/2 to 2 hours

• The colour is retained for a longer period.

• The emulsion paints surface can be washed by water so this paint not use for external wall.

24. What is the function of a vehicle in an oil borne paint? [JSSC JE (GEN. ENGG.)- 03.11.2022]

Correct Answer: (a) It holds the ingredients of the paint in liquid suspension
Solution:Vehicle or carrier– This is a liquid substance which holds the ingredients of the paint in suspension, the most common material is linseed oil.

25. The function of adding gypsum in the manufacture of ordinary Portland cement is: [JSSC JE (GEN. ENGG.)- 03.11.2022]

Correct Answer: (c) to prevent flash setting of cement
Solution:The purpose of adding gypsum is to coat the cement particles by interfering with the process of hydration of the cement particles. This retards the setting of cement.

26. As per the Bureau of Indian Standards, burnt clay bricks are classified based on their minimum average compressive strength as: [JSSC JE (GEN. ENGG.)- 03.11.2022]

Correct Answer: (a) 11 classes
Solution:

As per IS 1077 : 1992

Class DesignationAverage Compressive Strength (Not less than) (N/mm²)
3535.0
3030.0
2525.0
2020.0
17.517.5
1515.0
12.512.5
1010.0
7.57.5
55.0
3.53.5

27. The rocks formed due to alteration of original structure under heat and excessive pressure are called- [JSSC JE (GEN. ENGG)-2017]

Correct Answer: (c) Metamorphic rocks
Solution:Metamorphic rocks–These rocks are formed from igneous or sedimentary rocks as a result of action of the earth movements, temperature changes, liquid pressure etc.

Example–

Original RockMetamorphic Rock
GraniteGneiss
SandstoneQuartzite
LimestoneMarble
ShaleSlate
MudstoneSlate

28. Eminently hydraulic lime has [BPSC AE (GEN. ENGG.)-2001]

Correct Answer: (c) about 25% clay content
Solution:Eminently hydraulic lime– In eminently Hydraulic lime has clayey impurities 20-30% and slakes with difficulty. Its initial setting lime is 2 hours and final setting time is 48 hours. It is used in damp places and for all structural purposes.

29. The silica in Portland cement is- [JSSC JE (GEN. ENGG)-2017 ]

Correct Answer: (b) 17 to 25%
Solution:Different constituent of OPC
IngredientsQuantityWork
Lime (CaO)62–67%Imparts strength and soundness of the cement
Silica (SiO₂)17–25%It also imparts strength to the cement
Alumina (Al₂O₃)3–8%Imparts quick setting to cement
Calcium sulphate (CaSO₄)3–4%Helps in increasing the initial setting time of cement
Iron Oxide (Fe₂O₃)3–4%Imparts strength, hardness and colour to cement
Magnesia (MgO)1–3%Imparts strength, hardness and colour to cement

30. The cement, widely used in retaining wall is [BPSC AE (GEN. ENGG.)-13.03.2022]

Correct Answer: (b) low heat cement
Solution:Low heat cement (IS : 12600)

• It is the type of cement which involves low heat of hydration than OPC.

• Heat of hydration of this cement at the age of 7 days is not more than 65 cal/gm and at the age of 28 days is not more than 75 cal/gm.

• This cement is produced by reducing the proportion of C₃S, C₃A and increasing the proportion of C₂S.

• The cement offers higher resistance attack of sulphur and lower rate of gain of strength.

• This content finds the application in mass concreting works eg. hydraulic structures, foundation, retaining wall etc.

• Compressive strength of this cement at the age of:

3 days ≮ 10 N/mm²

7 days ≮ 16 N/mm²

28 days ≮ 35 N/mm²

• Minimum initial setting time ≮ 60 minutes

• Final setting time ≯ 600 minutes.