BUILDING MATERIALS CHAPTER WISE

ᑭᑎ ᒪEᗩᖇᑎ ᗩᒪEᖇT

1 month ago

🏗️ BUILDING MATERIALS

(SSC JE | RRB JE | OSSC JE | State JE/AE)

📌 CHAPTER 1: STONES

🔹 1️⃣ ONE-PAGE PRECISE NOTES (HIGH-YIELD)

Stone = naturally occurring hard material
Used in foundations, masonry, bridges, roads
Strength depends on structure + mineral composition

⭐ Properties of Good Building Stone (VERY IMPORTANT)

High compressive strength
Low porosity
Durable
Weather resistant

⭐ Common Stones & Uses (PYQ)

Granite → heavy structures
Basalt → road metal
Limestone → cement manufacture

⚠️ Defects in Stones

Cracks, vents, sand holes → reduce strength

🔹 2️⃣ IMPORTANT FORMULAS

(No numericals generally asked from stones)

🔹 3️⃣ KEY TABLE

Stone	Major Use
Granite	Foundations
Basalt	Roads
Marble	Flooring
Limestone	Cement

🔹 4️⃣ NUMERICAL EXAMPLES

(Not generally asked – conceptual only)

🔹 5️⃣ MCQs (Sample)

Granite is preferred for:
A. Decoration
B. Road metal
C. Heavy structures
D. Cement
✅ Ans: C

📌 CHAPTER 2: BRICKS

🔹 1️⃣ ONE-PAGE PRECISE NOTES

Brick = burnt clay product
Standard size (India): 19 × 9 × 9 cm
With mortar: 20 × 10 × 10 cm ⭐

⭐ Types (Frequently Asked)

First class
Second class
Third class
Fly ash bricks

⭐ First Class Brick (PYQ)

Water absorption ≤ 20%
Compressive strength ≥ 10.5 MPa

🔹 2️⃣ IMPORTANT FORMULAS

🔸 Water Absorption

$WA=W2−W1W1×100\boxed{WA = \frac{W_2 – W_1}{W_1} \times 100}$

🔸 Bricks per m³

$bricks/m3\boxed{500\ \text{bricks/m}^3}$

🔹 3️⃣ KEY TABLE

Brick Class	Water Absorption
First	≤ 20%
Second	≤ 22%
Third	> 25%

🔹 4️⃣ NUMERICAL EXAMPLES

Example 1 (Easy)

No. of bricks in 2 m³ masonry?
= 2 × 500 = 1000 bricks

Example 2 (Moderate)

Dry wt = 3 kg, wet wt = 3.6 kg

$\frac{0.6}{3}×100 = 20\%$

→ First class brick

Example 3 (Advanced)

1500 bricks required → Volume?

$\frac{1500}{500} = 3\ \text{m}^3$

📌 CHAPTER 3: CEMENT (HIGHEST WEIGHTAGE)

🔹 1️⃣ ONE-PAGE PRECISE NOTES

Cement sets & hardens due to hydration
Most used binding material

⭐ Cement Compounds (EXTREMELY IMPORTANT)

Compound	Function
C₃S	Early strength ⭐
C₂S	Later strength
C₃A	Initial setting
C₄AF	Colour

⚠️ Gypsum controls setting time

🔹 2️⃣ IMPORTANT FORMULAS / VALUES

Initial setting time ≥ 30 min
Final setting time ≤ 10 hrs

🔹 3️⃣ KEY TABLE – GRADES OF CEMENT

Grade	Strength (MPa)
33	33
43	43
53	53

🔹 4️⃣ NUMERICAL EXAMPLES

Example 1

Early strength compound?
→ C₃S

Example 2

Flash set caused by?
→ C₃A

Example 3 (Conceptual)

Why gypsum added?
→ To control setting time

📌 CHAPTER 4: LIME

🔹 1️⃣ ONE-PAGE NOTES

Oldest binding material
Used in heritage structures

Types

Fat lime
Hydraulic lime
Poor lime

⭐ Lime mortar is flexible but weak

📌 CHAPTER 5: TIMBER

🔹 1️⃣ ONE-PAGE NOTES

Used in doors, windows, roofs
Strength depends on seasoning

⭐ Defects (PYQ)

Dry rot → fungi
Warping → improper seasoning
Knots → weak zones

📌 CHAPTER 6: AGGREGATES

🔹 1️⃣ ONE-PAGE NOTES

Inert material in concrete
Occupies 60–75% volume ⭐

Shape Effect

Angular → strength
Rounded → workability

🧠 50 MIXED MCQs (25 THEORY + 25 NUMERICAL)

🔹 THEORY (1–25)

✔ Cement compounds
✔ Brick properties
✔ Timber defects
✔ Stone uses
✔ Aggregates

🔹 NUMERICAL (26–50)

✔ Brick count
✔ Absorption
✔ Cement setting time
✔ Volume calculations

🎯 FINAL EXAM TRICKS

⭐ Remember 500 bricks/m³
⭐ C₃S = early strength
⭐ Gypsum ≠ strength
⚠️ Setting ≠ drying
⚠️ Brick size confusion is common

🧠 BUILDING MATERIALS – 50 MIXED MCQs

(SSC JE | RRB JE | OSSC JE Pattern)

🔹 THEORY MCQs (Q1–Q25)

Q1. Early strength of cement is mainly due to:

A. C₂S
B. C₃S
C. C₃A
D. C₄AF

✅ Answer: B
📝 Explanation: C₃S hydrates rapidly → early strength.
⚠️ Trap: C₂S gives later strength.

Q2. Which compound is responsible for flash setting of cement?

A. C₂S
B. C₃S
C. C₃A
D. C₄AF

✅ Answer: C
📝 Explanation: C₃A reacts very fast with water. Gypsum controls it.

Q3. Standard size of brick in India (without mortar) is:

A. 20 × 10 × 10 cm
B. 19 × 9 × 9 cm
C. 18 × 8 × 8 cm
D. 22 × 11 × 11 cm

✅ Answer: B
📝 Explanation: Very common SSC JE question.

Q4. Water absorption of first-class brick should not exceed:

A. 15%
B. 18%
C. 20%
D. 25%

✅ Answer: C

Q5. Which stone is best suited for road metal?

A. Marble
B. Limestone
C. Granite
D. Basalt

✅ Answer: D
📝 Explanation: Basalt → 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

✅ Answer: B

Q7. Soundness of cement is tested by:

A. Vicat apparatus
B. Blaine apparatus
C. Le-Chatelier apparatus
D. Compression testing machine

✅ 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

✅ Answer: C

Q9. Which aggregate shape provides maximum strength?

A. Rounded
B. Angular
C. Flaky
D. Elongated

✅ Answer: B

Q10. Timber defect caused by fungi is:

A. Knot
B. Warp
C. Dry rot
D. Twist

✅ Answer: C

Q11. Warping in timber occurs due to:

A. Insects
B. Overloading
C. Improper seasoning
D. Fungal attack

✅ 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

✅ Answer: C

Q13. Which stone is commonly used for cement manufacture?

A. Granite
B. Basalt
C. Limestone
D. Slate

✅ Answer: C

Q14. Fly ash bricks are:

A. Weak
B. Expensive
C. Environment friendly
D. High water absorbing

✅ Answer: C

Q15. Aggregates generally occupy how much volume of concrete?

A. 30–40%
B. 40–50%
C. 60–75%
D. 80–90%

✅ Answer: C

Q16. Which cement compound contributes least to strength?

A. C₂S
B. C₃S
C. C₃A
D. C₄AF

✅ Answer: D

Q17. Engineering bricks are preferred because of:

A. Low cost
B. High porosity
C. High strength & low absorption
D. Smooth surface

✅ Answer: C

Q18. Setting of cement is due to:

A. Drying
B. Oxidation
C. Hydration
D. Carbonation

✅ Answer: C
⚠️ Very common conceptual trap

Q19. Which timber is best for structural works?

A. Softwood
B. Sapwood
C. Hardwood
D. Green wood

✅ Answer: C

Q20. Excess gypsum in cement causes:

A. Flash setting
B. Faster hardening
C. Delayed setting
D. Increase strength

✅ Answer: C

Q21. Best stone for ornamental works is:

A. Granite
B. Marble
C. Basalt
D. Sandstone

✅ 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

✅ Answer: D

Q23. Which aggregate property resists wear and impact?

A. Shape
B. Toughness
C. Texture
D. Grading

✅ Answer: B

Q24. Which test determines compressive strength of cement?

A. Vicat test
B. Cube test
C. Blaine test
D. Soundness test

✅ 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

✅ Answer: C

🔹 NUMERICAL MCQs (Q26–Q50)

Q26. Number of bricks required for 1 m³ brick masonry is approximately:

A. 400
B. 450
C. 500
D. 550

✅ Answer: C
📝 Exam Tip: Always remember 500 bricks/m³

Q27. Bricks required for 3 m³ brickwork:

A. 1000
B. 1200
C. 1500
D. 1800

✅ 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%

✅ Answer: C
📝 $20\%$

Q29. A brick absorbs 400 g of water. Dry weight = 2 kg. Absorption = ?

A. 10%
B. 15%
C. 20%
D. 25%

✅ 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

✅ Answer: C

Q31. Final setting time of OPC should NOT exceed:

A. 6 hours
B. 8 hours
C. 10 hours
D. 12 hours

✅ Answer: C

Q32. If 2000 bricks are used, approximate volume of brickwork is:

A. 2 m³
B. 3 m³
C. 4 m³
D. 5 m³

✅ Answer: C
📝 $2000 \div 500 = 4$

Q33. A brick has water absorption of 22%. It belongs to:

A. First class
B. Second class
C. Third class
D. Rejected

✅ Answer: B

Q34. Cement grade required for minimum strength 53 MPa is:

A. OPC 33
B. OPC 43
C. OPC 53
D. PPC

✅ Answer: C

Q35. Volume of 1000 bricks masonry is approximately:

A. 1 m³
B. 2 m³
C. 3 m³
D. 4 m³

✅ Answer: B

Q36. Dry wt = 2.5 kg, wet wt = 3 kg. Absorption = ?

A. 15%
B. 18%
C. 20%
D. 25%

✅ Answer: C

Q37. If brick absorption is 26%, brick is classified as:

A. First class
B. Second class
C. Third class
D. Engineering brick

✅ Answer: C

Q38. Standard brick with mortar size is:

A. 19×9×9 cm
B. 20×10×10 cm
C. 22×11×11 cm
D. 23×11×7.5 cm

✅ Answer: B

Q39. A bag of cement weighs:

A. 40 kg
B. 45 kg
C. 50 kg
D. 55 kg

✅ Answer: C

Q40. If fineness of cement increases, strength will:

A. Decrease
B. Increase
C. Remain same
D. Become zero

✅ Answer: B

Q41. If aggregate content is 70%, cement paste content is:

A. 20%
B. 25%
C. 30%
D. 35%

✅ Answer: C

Q42. OPC 43 grade cement attains 43 MPa strength at:

A. 3 days
B. 7 days
C. 14 days
D. 28 days

✅ Answer: D

Q43. Minimum initial setting time helps in:

A. Transport
B. Placing
C. Compaction
D. All of the above

✅ Answer: D

Q44. Number of bricks in 0.5 m³ masonry is:

A. 200
B. 250
C. 300
D. 350

✅ Answer: B

Q45. Excess water absorption in bricks causes:

A. Strength increase
B. Efflorescence
C. Durability
D. Hardness

✅ Answer: B

Q46. Volume of 500 bricks masonry equals:

A. 0.5 m³
B. 1 m³
C. 1.5 m³
D. 2 m³

✅ Answer: B

Q47. Which cement is suitable for cold weather concreting?

A. OPC 33
B. Rapid hardening cement
C. Low heat cement
D. PPC

✅ 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

✅ Answer: B

Q49. Cement cube test is conducted at:

A. 3 days
B. 7 days
C. 28 days
D. All of the above

✅ Answer: D

Q50. If 250 bricks are used, volume of brick masonry is:

A. 0.25 m³
B. 0.5 m³
C. 0.75 m³
D. 1 m³

✅ Answer: B