WATER TO CEMENT RATIO
WATER TO CEMENT RATIO
The ratio between water and cement by weight is known
as Water Cement Ratio.
The quantity of water added to the cement while
preparing concrete mixes has been known to exert tremendous influence on the
quality of concrete.
Cement and water are the only two chemically active
elements in concrete.
By their combination they form a glue like binder
paste which create bond between fine aggegates and course aggregate.
Water is the most important element in concrete
governing all the properties of cement concrete like durability, strength and
fire resistance.
THE FUNCTIONS OF MIXING WATER ARE :
·
When water mix with cement ,The
chemical reaction starts between water and cement ,
·
This reaction starts the hydration in
past from that the cement and water past
starts setting according to the type of cement
and type of construction.
- To make the concrete workable so that
it can be placed easily and uniformly between the reinforcing bars and in the
corners.
- The strength of the concrete depends
on water to cement ratio.
Therefore we need to use the amount of water carefully
while mixing the concrete.
Too much water can increase the workability ,but it
will also effect the strength of concrete.
If less water used it will increase the strength and durability
but will decrease the workability.
It can be seen that lower water cement ratio could be
used when the concrete is vibrated to achieve higher strength, whereas,
comparatively, higher water cement ratio is required when concrete is hand
compacted.
In both cases when the water cement ratio is below the
practical limit, the strength of concrete falls rapidly due to introduction of
air voids.
FUNCTION OF WATER IN CONCRETE.
1.
It hydrates the cement, which is an
essential chemical reaction for formation of complex silicate crystalline gels
that are responsible for the strength of the cement.
2.
It lubricates all the concrete
ingredients, by passing around them in the form of films. Hence it is responsible
for the plasticity and mobility of concrete which define its workability.
EFFECTS OF EXTRA WATER IN CONCRETE
Any extra amount of water
added to concrete ingredients at the time of mixing also course segregation of
aggregates during transport and placement.
WHAT IS BLEEDING OF CONCRETE
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