Are you told Add some water, tthe concrete hardâ looks very?
Is this correct? Adding more water (Drinking water Cement Ratio) at the website level to improve the concrete workability ???
Water Cement Ratio methods the ratio between your weight of drinking water to the pounds of cement found in concrete mix.
Normally drinking water cement ratio drops under 0.4 to 0.6 according to IS Program code 10262 (2009) for nominal mix (M10, M15 â? M25)
Everybody knows that water cement ratio will directly affect the effectiveness of concrete. Either the strength is increased because of it if found in correct proportion or decrease it.
But perhaps you have consider it why we have been using water if it has so much difficulty?
Role of Water in Concrete
Concrete is really a macro content.
It includes micro ingredients such as for example cement, sand, fine aggregate & Coarse aggregate. Â In order to obtain high strength concrete which withstands around our desired compressive strength, We are in need of correct proportion of admixture to mix these materials.
Here comes the Water that may initiate this chemical process with the addition of 23%-25% of the cement volume. This initiates the chemical process and makes 15% of water cement paste also called a gel to fill the voids in the concrete.
Effects of an excessive amount of water in concrete
As mentioned above we are in need of 23% of water to initiate the chemical process on cement.
Adding more water than this allowable Water cement limit will in actuality affect the strength.
If we continue adding water to improve the workability then your concrete has plenty of fluid materials where in fact the aggregates will relax. After the water evaporated it leaves plenty of voids in concrete which affects the concrete strength.
But if we follow the rules in order to keep up with the strength of the concrete then it'll affect the concrete workability and make us hard to take care of and place them.
Wait one minute.
Have you any idea what's Workability Of Concrete?
Workability means the power of concrete to take care of, transport and placing without the segregation. The concrete reported to be workable if it could be handled easily, transported and placed without the segregation while placing it in site.
Thatâs why we have been using plasticisers & superplasticizers that will raise the workability without affecting the W/C Ratio.
How exactly to calculate Water Cement Ratio? â?W/C Ratio Calculation
We donât actually calculate the Water Cement Ratio.
It really is selected from various workability test in line with the structural members, concrete strength, transportation, collection of aggregation etc.
At Site Level, we are able to utilize the below calculation for the nominal mix.
This is a guide so make your personal judgment.
Water Cement Ratio IS 10262 (2009) Code Chart
Calculation of Water Quantity for Concrete
As you can plainly see from the Chart, the W/C Ratio varies from 0.4 to 0.7 based on exposure conditions.
If we have to calculate Water quantityÂ for concrete, discover the cement content for the quantity first.
If we Assume the mandatory cement volume as 50kg,
Required quantity of water = W/C Ratio X Cement Volume
Therefore,Â Required level of water =Â 0.5 X 50 kg = 25 litres / 50 kg cement bag.
For Design mix, the W/C Ratio shall rely upon the workability, strength requirements.
In IS 10262-2009Â ANNEX A. they will have explained the procedure for design mix.
Hope that can help you.
Water Cement Ratio Test
Hopefully now you've got a fair quantity of knowledge on Water Cement ratio.
It's time to try this vital task. How exactly to test water cement ratio?
We actually use Concrete Slump Test at the website level to check on this workability & Consistency which we will discuss in the upcoming post.