If we have wet sand and we don’t know the exact weight of dry sand, How do we adjust the w/c ratio and mix proportions?
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If we have wet sand and we don’t know the exact weight of dry sand, How do we adjust the w/c ratio and mix proportions?
Komal Bhandakkar
Well, this is the basic thing we need to understand while designing a mix.
As we know that, the volume of a 1-metre cube of wet concrete is equivalent to a 1.52-metre cube of dry concrete.
I will tell you one simple calculation with the help of an example, have a look;
Example:
Weight of wet sample= 1050gm
Weight of dry sample=1000gm
Total moisture content in percent=5%
Absorption as found on sand data sheet= 0.5%
Free moisture= Total Moisture – Absorbed Moisture.
i.e. Free Moisture = 5%-0.5%=4.5%
aviratdhodare
Water content in sand is determined seprately first and the requirements of water in concrete is accordingly adjusted to control w/c ratio required in the mix.
AdityaBhandakkar
Hi,
The maximum amount of water to cement ratio should be determined by the authority having jurisdiction based on the exposure conditions. The targeted water to cement ratio should be selected from the data available on the materials which actually used.
but if such data is not available then water to cement the should be selected from IS mix proportion table or ACI Table 6.9.4-a.
nikeetasharma
If you are working with wet or moisture sand and without any tech then ;
1. Just weigh a sample of aggregate from inside your stockpile in a metal or other heat resistance receptacle.This must be a tare weight.
2. Place this sample in an oven or any heating material to remove moisture.
3. Again weight the sample of aggregate.
4. Subtract weight of 3 from 1 .
5. When using aggregate from this stockpile for your concrete mix reduce water addition by weight determined in point 4 for each unit weight determined at 1 that you add.
After this you will get to see water releasing from your aggregate. Also understand that the moisture content is most important on your sand less so in your course aggregate.
Omprakash Dhawale
Sir,
If we are dealing with moist sand and we used it in our concrete mix then we just have to find out their free moisture content and fix it in mix proportion accordingly.