๐๏ธ BUILDING MATERIALS
(SSC JE | RRB JE | OSSC JE | State JE/AE)
๐ CHAPTER 1: STONES
๐น 1๏ธโฃ ONE-PAGE PRECISE NOTES (HIGH-YIELD)
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Stone = naturally occurring hard material
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Used in foundations, masonry, bridges, roads
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Strength depends on structure + mineral composition
โญ Properties of Good Building Stone (VERY IMPORTANT)
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High compressive strength
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Low porosity
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Durable
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Weather resistant
โญ Common Stones & Uses (PYQ)
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Granite โ heavy structures
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Basalt โ road metal
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Limestone โ cement manufacture
โ ๏ธ Defects in Stones
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Cracks, vents, sand holes โ reduce strength
๐น 2๏ธโฃ IMPORTANT FORMULAS
(No numericals generally asked from stones)
๐น 3๏ธโฃ KEY TABLE
| Stone | Major Use |
|---|---|
| Granite | Foundations |
| Basalt | Roads |
| Marble | Flooring |
| Limestone | Cement |
๐น 4๏ธโฃ NUMERICAL EXAMPLES
(Not generally asked โ conceptual only)
๐น 5๏ธโฃ MCQs (Sample)
Granite is preferred for:
A. Decoration
B. Road metal
C. Heavy structures
D. Cement
โ
Ans: C
๐ CHAPTER 2: BRICKS
๐น 1๏ธโฃ ONE-PAGE PRECISE NOTES
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Brick = burnt clay product
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Standard size (India): 19 ร 9 ร 9 cm
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With mortar: 20 ร 10 ร 10 cm โญ
โญ Types (Frequently Asked)
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First class
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Second class
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Third class
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Fly ash bricks
โญ First Class Brick (PYQ)
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Water absorption โค 20%
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Compressive strength โฅ 10.5 MPa
๐น 2๏ธโฃ IMPORTANT FORMULAS
๐ธ Water Absorption
WA=W2โW1W1ร100\boxed{WA = \frac{W_2 – W_1}{W_1} \times 100}
๐ธ Bricks per mยณ
500ย bricks/m3\boxed{500\ \text{bricks/m}^3}
๐น 3๏ธโฃ KEY TABLE
| Brick Class | Water Absorption |
|---|---|
| First | โค 20% |
| Second | โค 22% |
| Third | > 25% |
๐น 4๏ธโฃ NUMERICAL EXAMPLES
Example 1 (Easy)
No. of bricks in 2 mยณ masonry?
= 2 ร 500 = 1000 bricks
Example 2 (Moderate)
Dry wt = 3 kg, wet wt = 3.6 kg
WA=0.63ร100=20%WA = \frac{0.6}{3}ร100 = 20\%
โ First class brick
Example 3 (Advanced)
1500 bricks required โ Volume?
V=1500500=3ย m3V = \frac{1500}{500} = 3\ \text{m}^3
๐ CHAPTER 3: CEMENT (HIGHEST WEIGHTAGE)
๐น 1๏ธโฃ ONE-PAGE PRECISE NOTES
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Cement sets & hardens due to hydration
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Most used binding material
โญ Cement Compounds (EXTREMELY IMPORTANT)
| Compound | Function |
|---|---|
| CโS | Early strength โญ |
| CโS | Later strength |
| CโA | Initial setting |
| CโAF | Colour |
โ ๏ธ Gypsum controls setting time
๐น 2๏ธโฃ IMPORTANT FORMULAS / VALUES
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Initial setting time โฅ 30 min
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Final setting time โค 10 hrs
๐น 3๏ธโฃ KEY TABLE โ GRADES OF CEMENT
| Grade | Strength (MPa) |
|---|---|
| 33 | 33 |
| 43 | 43 |
| 53 | 53 |
๐น 4๏ธโฃ NUMERICAL EXAMPLES
Example 1
Early strength compound?
โ CโS
Example 2
Flash set caused by?
โ CโA
Example 3 (Conceptual)
Why gypsum added?
โ To control setting time
๐ CHAPTER 4: LIME
๐น 1๏ธโฃ ONE-PAGE NOTES
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Oldest binding material
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Used in heritage structures
Types
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Fat lime
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Hydraulic lime
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Poor lime
โญ Lime mortar is flexible but weak
๐ CHAPTER 5: TIMBER
๐น 1๏ธโฃ ONE-PAGE NOTES
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Used in doors, windows, roofs
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Strength depends on seasoning
โญ Defects (PYQ)
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Dry rot โ fungi
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Warping โ improper seasoning
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Knots โ weak zones
๐ CHAPTER 6: AGGREGATES
๐น 1๏ธโฃ ONE-PAGE NOTES
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Inert material in concrete
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Occupies 60โ75% volume โญ
Shape Effect
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Angular โ strength
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Rounded โ workability
๐ง 50 MIXED MCQs (25 THEORY + 25 NUMERICAL)
๐น THEORY (1โ25)
โ Cement compounds
โ Brick properties
โ Timber defects
โ Stone uses
โ Aggregates
๐น NUMERICAL (26โ50)
โ Brick count
โ Absorption
โ Cement setting time
โ Volume calculations
๐ฏ FINAL EXAM TRICKS
โญ Remember 500 bricks/mยณ
โญ CโS = early strength
โญ Gypsum โ strength
โ ๏ธ Setting โ drying
โ ๏ธ Brick size confusion is common
๐ง BUILDING MATERIALS โ 50 MIXED MCQs
(SSC JE | RRB JE | OSSC JE Pattern)
๐น THEORY MCQs (Q1โQ25)
Q1. Early strength of cement is mainly due to:
A. CโS
B. CโS
C. CโA
D. CโAF
โ
Answer: B
๐ Explanation: CโS hydrates rapidly โ early strength.
โ ๏ธ Trap: CโS gives later strength.
Q2. Which compound is responsible for flash setting of cement?
A. CโS
B. CโS
C. CโA
D. CโAF
โ
Answer: C
๐ Explanation: CโA reacts very fast with water. Gypsum controls it.
Q3. Standard size of brick in India (without mortar) is:
A. 20 ร 10 ร 10 cm
B. 19 ร 9 ร 9 cm
C. 18 ร 8 ร 8 cm
D. 22 ร 11 ร 11 cm
โ
Answer: B
๐ Explanation: Very common SSC JE question.
Q4. Water absorption of first-class brick should not exceed:
A. 15%
B. 18%
C. 20%
D. 25%
โ Answer: C
Q5. Which stone is best suited for road metal?
A. Marble
B. Limestone
C. Granite
D. Basalt
โ
Answer: D
๐ Explanation: Basalt โ hard, tough, abrasion resistant.
Q6. Which test is used to determine setting time of cement?
A. Blaine test
B. Vicat test
C. Le-Chatelier test
D. Cube test
โ Answer: B
Q7. Soundness of cement is tested by:
A. Vicat apparatus
B. Blaine apparatus
C. Le-Chatelier apparatus
D. Compression testing machine
โ Answer: C
Q8. Main function of aggregates in concrete is to:
A. Increase workability
B. Increase setting time
C. Provide strength & bulk
D. Reduce hydration
โ Answer: C
Q9. Which aggregate shape provides maximum strength?
A. Rounded
B. Angular
C. Flaky
D. Elongated
โ Answer: B
Q10. Timber defect caused by fungi is:
A. Knot
B. Warp
C. Dry rot
D. Twist
โ Answer: C
Q11. Warping in timber occurs due to:
A. Insects
B. Overloading
C. Improper seasoning
D. Fungal attack
โ Answer: C
Q12. Which cement is preferred for mass concrete works?
A. OPC 53
B. Rapid hardening cement
C. Low heat cement
D. High alumina cement
โ Answer: C
Q13. Which stone is commonly used for cement manufacture?
A. Granite
B. Basalt
C. Limestone
D. Slate
โ Answer: C
Q14. Fly ash bricks are:
A. Weak
B. Expensive
C. Environment friendly
D. High water absorbing
โ Answer: C
Q15. Aggregates generally occupy how much volume of concrete?
A. 30โ40%
B. 40โ50%
C. 60โ75%
D. 80โ90%
โ Answer: C
Q16. Which cement compound contributes least to strength?
A. CโS
B. CโS
C. CโA
D. CโAF
โ Answer: D
Q17. Engineering bricks are preferred because of:
A. Low cost
B. High porosity
C. High strength & low absorption
D. Smooth surface
โ Answer: C
Q18. Setting of cement is due to:
A. Drying
B. Oxidation
C. Hydration
D. Carbonation
โ
Answer: C
โ ๏ธ Very common conceptual trap
Q19. Which timber is best for structural works?
A. Softwood
B. Sapwood
C. Hardwood
D. Green wood
โ Answer: C
Q20. Excess gypsum in cement causes:
A. Flash setting
B. Faster hardening
C. Delayed setting
D. Increase strength
โ Answer: C
Q21. Best stone for ornamental works is:
A. Granite
B. Marble
C. Basalt
D. Sandstone
โ Answer: B
Q22. Which brick is moulded using industrial waste?
A. First-class brick
B. Second-class brick
C. Engineering brick
D. Fly ash brick
โ Answer: D
Q23. Which aggregate property resists wear and impact?
A. Shape
B. Toughness
C. Texture
D. Grading
โ Answer: B
Q24. Which test determines compressive strength of cement?
A. Vicat test
B. Cube test
C. Blaine test
D. Soundness test
โ Answer: B
Q25. Which is NOT a property of good building stone?
A. High compressive strength
B. Durability
C. High water absorption
D. Low porosity
โ Answer: C
๐น NUMERICAL MCQs (Q26โQ50)
Q26. Number of bricks required for 1 mยณ brick masonry is approximately:
A. 400
B. 450
C. 500
D. 550
โ
Answer: C
๐ Exam Tip: Always remember 500 bricks/mยณ
Q27. Bricks required for 3 mยณ brickwork:
A. 1000
B. 1200
C. 1500
D. 1800
โ Answer: C
Q28. A brick weighs 3 kg dry and 3.6 kg wet. Water absorption (%) is:
A. 10%
B. 15%
C. 20%
D. 25%
โ
Answer: C
๐ (0.6/3)ร100=20%(0.6/3)ร100 = 20\%
Q29. A brick absorbs 400 g of water. Dry weight = 2 kg. Absorption = ?
A. 10%
B. 15%
C. 20%
D. 25%
โ Answer: C
Q30. Initial setting time of cement should NOT be less than:
A. 10 min
B. 20 min
C. 30 min
D. 60 min
โ Answer: C
Q31. Final setting time of OPC should NOT exceed:
A. 6 hours
B. 8 hours
C. 10 hours
D. 12 hours
โ Answer: C
Q32. If 2000 bricks are used, approximate volume of brickwork is:
A. 2 mยณ
B. 3 mยณ
C. 4 mยณ
D. 5 mยณ
โ
Answer: C
๐ 2000รท500=42000 รท 500 = 4
Q33. A brick has water absorption of 22%. It belongs to:
A. First class
B. Second class
C. Third class
D. Rejected
โ Answer: B
Q34. Cement grade required for minimum strength 53 MPa is:
A. OPC 33
B. OPC 43
C. OPC 53
D. PPC
โ Answer: C
Q35. Volume of 1000 bricks masonry is approximately:
A. 1 mยณ
B. 2 mยณ
C. 3 mยณ
D. 4 mยณ
โ Answer: B
Q36. Dry wt = 2.5 kg, wet wt = 3 kg. Absorption = ?
A. 15%
B. 18%
C. 20%
D. 25%
โ Answer: C
Q37. If brick absorption is 26%, brick is classified as:
A. First class
B. Second class
C. Third class
D. Engineering brick
โ Answer: C
Q38. Standard brick with mortar size is:
A. 19ร9ร9 cm
B. 20ร10ร10 cm
C. 22ร11ร11 cm
D. 23ร11ร7.5 cm
โ Answer: B
Q39. A bag of cement weighs:
A. 40 kg
B. 45 kg
C. 50 kg
D. 55 kg
โ Answer: C
Q40. If fineness of cement increases, strength will:
A. Decrease
B. Increase
C. Remain same
D. Become zero
โ Answer: B
Q41. If aggregate content is 70%, cement paste content is:
A. 20%
B. 25%
C. 30%
D. 35%
โ Answer: C
Q42. OPC 43 grade cement attains 43 MPa strength at:
A. 3 days
B. 7 days
C. 14 days
D. 28 days
โ Answer: D
Q43. Minimum initial setting time helps in:
A. Transport
B. Placing
C. Compaction
D. All of the above
โ Answer: D
Q44. Number of bricks in 0.5 mยณ masonry is:
A. 200
B. 250
C. 300
D. 350
โ Answer: B
Q45. Excess water absorption in bricks causes:
A. Strength increase
B. Efflorescence
C. Durability
D. Hardness
โ Answer: B
Q46. Volume of 500 bricks masonry equals:
A. 0.5 mยณ
B. 1 mยณ
C. 1.5 mยณ
D. 2 mยณ
โ Answer: B
Q47. Which cement is suitable for cold weather concreting?
A. OPC 33
B. Rapid hardening cement
C. Low heat cement
D. PPC
โ Answer: B
Q48. Increase in fineness of cement results in:
A. Lower heat of hydration
B. Faster strength gain
C. Delayed setting
D. Reduced workability
โ Answer: B
Q49. Cement cube test is conducted at:
A. 3 days
B. 7 days
C. 28 days
D. All of the above
โ Answer: D
Q50. If 250 bricks are used, volume of brick masonry is:
A. 0.25 mยณ
B. 0.5 mยณ
C. 0.75 mยณ
D. 1 mยณ
โ Answer: B