How do you prevent segregation in concrete? | Q & A

Segregation is the separation of coarse aggregate from mortar in fresh concrete. It weakens concrete and causes honeycombing.

Causes of Segregation (Brief)

• Excess water (high water–cement ratio)

• Improper handling and placing

• Excessive free fall

• Over-vibration

Methods to Prevent Segregation 1. Proper Mix Design

• Use correct water–cement ratio

• Well-graded aggregates

• Adequate fine aggregate content

2. Controlled Water Addition

• Do not add extra water on site

• Use approved admixtures to improve workability instead of water

3. Proper Handling & Transportation

• Avoid long drops during loading/unloading

• Use chute, pump, or tremie where required

• Prevent jolting during transport

4. Limit Free Fall of Concrete

• Free fall should not exceed 1.5 m

• Use drop chutes for columns and walls

5. Proper Placing Method

• Place concrete in layers

• Do not push or drag concrete over long distances

6. Correct Compaction Technique

• Use vibrators properly

• Avoid over-vibration

• Insert vibrator vertically and withdraw slowly

7. Maintain Proper Workability

• Concrete should be workable but not too wet

• Check slump before pouring

One-Line Interview Answer (Perfect)

Segregation is prevented by proper mix design, controlled water–cement ratio, limited free fall, correct placing and vibration techniques, and avoiding over-vibration or excess water.