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Fat lime composition, properties, uses

Short answer

Fat lime contains over 95% CaO, is white, slakes violently, sets slowly in air by carbonation, has high plasticity and low strength. Used for whitewashing, plaster, mortar with surkhi, bricks and in cement manufacture.

Discuss the composition, properties and uses of fat lime.

Fat lime (high calcium, rich or pure lime) is obtained by burning nearly pure limestone.

Composition

Contains over 95% calcium oxide (CaO) with less than 5% of clay and other impurities.

Properties

  • Pure white colour.
  • Slakes vigorously with water, producing much heat and expanding to 2 to 2.5 times its volume.
  • Sets and hardens slowly in air by absorbing CO₂ (carbonation); does not set under water.
  • High plasticity and good workability.
  • Low strength compared to hydraulic lime, and soluble in water.

Uses

  1. Whitewashing and colour washing.
  2. Plastering walls and as mortar for ordinary masonry in dry places.
  3. Mixed with pozzolana (surkhi) for hydraulic mortar.
  4. Making bricks, putty, and in the manufacture of cement and glass.

✓ Answer checked by Claude Opus 5.5 (high effort)

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