WATER
Water plays the vital role in concrete mix or and cement mixture. As water is used only to mix the materials properly and requirement of heat of hydration. Now if the water cement ratio is less we do not get the workability and if water cement ratio is less we see bleeding and in long terms we see cracks { as excess of water come's out}. So we have to take proper precautions to maintain proper water cement ratio.Normally, 0.55 W/C ratio is used for piratical workability, for workable concrete which can be compacted properly and with ease, w/c ratio has to be a little more than what is needed theoretically, note that although w/c ratio is little higher, the strength of concrete may be more if compaction is good.
In general we can take 30 ltr. to 32 ltr. of portable water for 1 bags of cement . {If we are not using admixture}
Relation between cube strength and water cement ratio by weight
Sr. No.
|
Water cement ratio by weight
|
Cube crushing strength ( kg/sq.cm)
|
|
7 days
|
28 days
|
||
1
|
0.35
|
400
|
530
|
2
|
0.40
|
350
|
470
|
3
|
0.45
|
300
|
420
|
4
|
0.5
|
250
|
370
|
5
|
0.55
|
220
|
320
|
6
|
0.60
|
180
|
280
|
7
|
0.65
|
150
|
250
|
8
|
0.70
|
130
|
220
|
9
|
0.75
|
110
|
200
|
10
|
0.80
|
105
|
180
|
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