Complete Guide to Crush (Bajri): Types, Uses, Quantity Calculation & Price in Pakistan (2025)

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Introduction – What is Crush (Bajri)?

Crush, commonly known as Bajri, is one of the most important coarse aggregates used in construction. It is obtained by crushing natural stones into different sizes and is a key ingredient of concrete (RCC).

Without quality crush, concrete cannot achieve the required compressive strength, durability, and load-bearing capacity. Therefore, crush selection is a critical factor in grey structure construction, both locally and internationally.

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1. What is Crush? (International Perspective)

From an engineering point of view, crush is defined as angular fragments of stone produced by mechanical crushing of rocks.

According to international standards (ASTM & BS):

• Crush particle size ranges from 4.75 mm to 40 mm
• It forms about 60–70% of concrete volume
• Angular shape provides better interlocking and strength

Crush is widely used in:

• Residential buildings
• High-rise structures
• Roads & pavements
• Bridges & infrastructure projects

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2. Role of Crush in Concrete

Crush performs the following key functions:

✔ Provides bulk and strength
✔ Reduces cement consumption
✔ Improves load resistance
✔ Enhances durability of RCC
✔ Controls shrinkage and cracking

Concrete without coarse aggregate would be weak, expensive, and impractical.

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3. Types of Crush Used in Construction

a) Margalla Crush

Margalla crush is considered the best quality crush in Pakistan.

Characteristics:

• Hard limestone
• Clean & durable
• Uniform shape

Uses:

• RCC slabs
• Beams & columns
• Foundations

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b) Sargodha Crush

Sargodha crush is widely used due to availability and cost.

Characteristics:

• Good strength
• Slightly higher absorption than Margalla

Uses:

• Residential RCC work
• Foundations

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c) Local Crush

Local crush is produced from nearby stone quarries.

Characteristics:

• Economical
• Quality depends on stone source

Uses:

• Low-cost construction
• Boundary walls
• Lean concrete

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4. Crush Sizes & Their Uses

Crush Size	Common Name	Uses
10 mm	Fine Crush	Slabs, thin RCC
20 mm	Standard Crush	RCC slabs, beams, columns
40 mm	Coarse Crush	Foundations, footings

👉 20 mm crush is most commonly used in house construction.

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5. Uses of Crush in Grey Structure

RCC Concrete

• Slabs
• Beams
• Columns
• Footings

Foundation Work

• Mass concrete
• PCC

Road & Pavement Work

• Base concrete
• Rigid pavements

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6. Crush Quantity Calculation (Practical Method)

a) Crush Quantity in Concrete

For 1 cubic meter of concrete (1:2:4):

• Crush ≈ 0.88 cubic meter

Example:

Concrete volume = 10 m³
Crush required = 10 × 0.88 = 8.8 m³

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b) Crush Quantity per Cement Bag

For standard RCC work:

• 1 cement bag requires approx. 4 CFT of crush

(Value may vary based on mix design)

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7. Quality Requirements of Good Crush

✔ Hard and durable
✔ Angular shape
✔ Free from dust & clay
✔ Properly graded
✔ Low water absorption

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8. Simple Site Tests for Crush Quality

Visual Inspection

• No flaky or elongated particles
• No dust coating

Soundness Test (Field Check)

• Two stones struck together should produce a ringing sound

Water Absorption Check

• Excessive water absorption indicates poor quality stone

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9. Current Crush / Bajri Rates in Pakistan (2025)

Average Market Prices (Approx.)

Crush Type	Unit	Price (PKR)
Margalla Crush	Per CFT	150 – 180
Sargodha Crush	Per CFT	130 – 160
Local Crush	Per CFT	110 – 140

Prices vary by:

• City
• Quarry location
• Transportation cost

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10. Storage & Handling of Crush

✔ Store on clean, firm ground
✔ Keep different sizes separate
✔ Avoid mixing with soil
✔ Wash dusty crush before use

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11. Common Mistakes to Avoid

❌ Using dusty or muddy crush
❌ Mixing different sizes randomly
❌ Ignoring grading requirements
❌ Using soft stone aggregates

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12. Frequently Asked Questions (FAQs)

Q1: Which crush is best for RCC work?
Margalla or well-graded Sargodha crush.

Q2: Can local crush be used for slabs?
Only if it meets strength and grading requirements.

Q3: Why angular crush is preferred?
Angular shape improves bonding and strength.

Q4: How much crush is needed per cubic meter of concrete?
Approximately 0.88 m³ for standard RCC.

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Conclusion

Crush (Bajri) is the backbone of concrete strength. Selecting the right type, size, and quality of crush ensures durable and safe construction. Proper estimation and quality control help avoid structural issues and unnecessary costs.