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Preventive measures against corrosion

Short answer

Prevent corrosion by using dense, impermeable concrete with low water-cement ratio (max 0.40–0.55), adequate cement and curing. Provide sufficient cover (20–75 mm by exposure), limit chlorides, use blended cements, and apply protective coatings or cathodic protection.

Write preventive measures against corrosion of steel reinforcement in concrete (how can reinforcement be protected from rusting on an RCC structure?).

Preventive measures against corrosion of reinforcement

  1. Dense, impermeable concrete: low w/c (max 0.40 to 0.55 by exposure), enough cement (min 300 to 360 kg/m3^3), good grading, full compaction and curing (IS 456, Table 5, Cl. 8).
  2. Adequate cover: nominal cover for RCC members of 20 mm (mild), 30 mm (moderate), 45 mm (severe), 50 mm (very severe) and 75 mm (extreme exposure), using cover blocks (IS 456, Table 16 and Cl. 26.4).
  3. Limit chlorides and sulphates in aggregate, water and admixtures (IS 456 Table 7; no sea water for RCC); avoid calcium chloride.
  4. Cement type: use PPC, slag or sulphate-resisting cement in aggressive areas, with fly ash or silica fume to reduce permeability.
  5. Crack control: limit crack width to 0.3 mm (IS 456, Cl. 35.3.2) by detailing and joints.
  6. Protected steel: epoxy-coated or galvanised bars, stainless steel, or corrosion-resistant (CRS / Fe 500D) TMT bars.
  7. Corrosion inhibitors (calcium nitrite) in the concrete mix.
  8. Surface protection: waterproof coating, sealers or cladding, and proper drainage with no ponding; a damp-proof course.
  9. Cathodic protection (sacrificial anode or impressed current) for existing structures, and timely repair of cracks.
  10. Regular inspection and maintenance.

✓ Answer checked by Claude Sonnet 5.5

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