DEFINITION

Water Cement Ratio means the ratio between the weight of water to the weight of cement used in concrete mix.

Normally water cement ratio falls under 0.4 to 0.6 as per IS Code 10262 (2009) for nominal mix (M10, M15 …. M25)

We all know that water cement ratio will directly affect the strength of concrete. Either it increases the strength if used in correct proportion or decrease it.

Role of Water in Concrete

It contains micro ingredients such as cement, sand, fine aggregate & Coarse aggregate. In order to acquire high strength concrete which withstands up to our desired compressive strength, We need correct proportion of admixture to combine these materials.

Here comes the Water which will initiate this chemical process by adding 23%-25% of the cement volume. This initiates the chemical process and makes 15% of water cement paste also known as a gel to fill the voids in the concrete.

Effects of too much water in concrete

As stated above we need 23% of water to initiate the chemical process on cement.

Adding more water than this allowable Water cement limit will actually affect the strength.

If we keep on adding water to increase the work-ability, then the concrete has lots of fluid materials where the aggregates will settle down. Once the water evaporated it leaves lots of voids in concrete which affects the concrete strength.