Causes:
Due to corrosion of reinforcement Steel.
Steel when corroded increases in volume and in course of time first cause
cracks in line with the dir. of reinforcement and later causes spalling of
concrete by dislodging cover of reinforcement from the body of concrete.
Preventive measures:
Ø Inadequate cover of
reinforcement.
Ø Permeable and porous
concrete.
Ø Carbonation.
Ø Alkali aggregate
reaction.
Ø Sulphate attack.
Ø Continuous dampness
& seepage in concrete.
Ø Use of CaCl as
accelerator.
Ø Passage of electric
current through concrete.
Ø Use of water having
chlorides & sulphates ( eg. Sea water, sewage, water ).
Presence of cracks in chloride which allow moisture to enter inside.
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