Curing
The
concrete surfaces are kept wet for a certain period after placing of concrete
so as to promote the hardening of cement. It consists of a control of
temperature and of the moisture movement from and into the concrete. The term
curing of concrete is used to indicate all such procedures and process.
Period
of concrete depend on the type of cement and nature of work. For ordinary
Portland cement, the curing period is about 7 to 14 days. If rapid hardening
cement is used, the curing period can be considerably reduced.
Following
are the purposes of the curing of concrete:
1.
The curing protects the concrete surfaces from sun and wind
2.
The presence of water is essential to cause the chemical action which
accompanies the setting of concrete.
3.
The strength of concrete gradually increases with age, if curing is
efficient.the increase in strength is sudden and rapid in early stages and it
continues slowly for an indefinite period.
4.
By proper curing, the durability and impermeability of concrete are increased
and shrinkage is reduced.
5.
The resistance of concrete to abrasion is considerably increased by proper
curing.
Following
are the basic factors on which the evaporation of water from the concrete
surface depends:
1.
Air temperature
2.
Fresh Concrete temperature
3.
Relative humidity; and
4.
Wind velocity.
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