What Is Water Cement Ratio | Water-Cement Ratio and Concrete Strength | Role of Water in Concrete

Water Cement Ratio

What Is Water Cement Ratio?

It is the ratio of cement and water utilized in the preparation of concrete. The quantity of water used at mixing concrete is very important.

If the percentage of water used is less, then there will not be a sufficient quantity of water to hydrate cement. It will result in weak and porous concrete.

Therefore, the usual tendency is to use too much water that gives a more workable mix, but it doesn’t give sound concrete. Too much water results in the segregation of aggregates and give porous concrete of low strength and low density.

water cement ratio by weight

Water-Cement Ratio as per Weight

A certain minimum proportion of water is necessary to hydrate the cement completely. To create the concrete sufficiently workable to be placed in position, some more water is needed.

So long as the concrete is sufficiently workable, for the way of placing used, its strength depends on the proportion of water to the cement in the mix.

The water-cement ratio shouldn’t be allowed to exceed the specified limits for various types of concrete and should usually be kept as low as the methods of placing will allow.

Abrahms, as a result of a large number of experiments, states that“with given materials and conditions of the test, the ratio of the quantity of mixing water into the quantity of cement alone determines the potency of concrete as long as the mix is of workable plasticity.

This is known as water-cement ratio law. According to this law, the strength of concrete won’t increase by simply increasing the quantity of cement unless the water-cement ratio is reduced.

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Required Water-Cement Ratio (British Standard Specifications)

Proportion Water-Cement Ratio
1:2:4 0.58
1:1.5:3 0.51
1:1:2 0.43

Water-Cement Ratio Table

Exposure Plain Cement Ratio Reinforced Cement Concrete
IS 10262 Minimum Cement Content W/C Ratio Grade Minimum Cement Content W/C Ratio Grade
Mild 220 0.60 300 0.55 M20
Moderate 240 0.60 M15 300 0.50 M25
Severe 250 0.50 M20 320 0.45 M30
Very Severe 260 0.45 M20 340 0.45 M35
Extreme 280 0.40 M25 360 0.40 M40

Different Water Cement Ratios

Different Water-cement ratios are utilized for different concrete applications. For high-quality concrete construction, a lower water-cement ratio of 0.4 could be employed. For concrete construction like sidewalks and drives, a w/c ratio ranging from 0.6 to 0.7 is normally used.

The practical range of water-cement ratio ranges from 0.3 to 0.8, which gives weak and stiff concrete, respectively. Weak concrete means a fairly wet concrete.

Compressive strength of about 5600 psi can be obtained in the concrete of the water-cement ratio 0.4. This value will go down to 2000 psi when a water-cement ratio of 0.8 is used.

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Water-Cement Ratio and Concrete Strength

The general concrete strength is reduced with the increase in the water-cement ratio. The addition of more water gives dilute paste, which has more pores at the micro-level.

These make the concrete weak and results in shrinkage and cracks and issues. The Cement and aggregates particles take the excess water that’s present in concrete.

This consumption is uncontrollable if a large excess of water is present in the concrete. Therefore, separate water channels are created, resulting in bleeding on the surface.

This creates weak zones in concrete that are susceptible to cracking under service loads.

Water-Cement Ratio and Concrete Strength

A lower water-cement ratio may contribute to high strength and high-quality concrete. But the water-cement ratio alone cannot give good concrete.

A good mix proportion and quality aggregates and binding materials contribute to the good mix design. A low water-cement ratio is thus one of the factors influencing good mix design.

Water-Cement Ratio and Permeability

Water-Cement Ratio and Permeability

A mix design using a lower water-cement ratio or higher cement content will give low permeability concrete. A high strength concrete tends to give less pervious concrete.

This will increase the durability of the concrete structure. The above figure shows the relationship between the concrete water-cement ratio and the coefficient of permeability.

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Role of Water in Concrete

It contains micro-ingredients like cement, sand, fine aggregate & Coarse aggregate. To acquire high strength concrete, that withstands up to our desired compressive strength, We need a correct proportion of admixture to combine those materials.

Here comes the Water, which will initiate this chemical process by incorporating 23% to 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.

How to calculate Water Cement Ratio? – W/C Ratio Calculation

We do not calculate the W/C Ratio.

It is selected from various workability tests based on the structural members, transportation, concrete strength, selection of aggregation, etc.

At Site Level, we can make use of the below calculation for the nominal mix.

It is a guide to make your judgment.

Water Cement Ratio as per IS 10262-2009 Table-5

As you can see from the Chart, the W/C Ratio varies from 0.4 to 0.7 depending on exposure conditions. If we need to calculate Water quantity for concrete, first find the cement content for the volume. If we Assume the required cement volume as 50kg, Required amount of water = W/C Ratio X Cement Volume Therefore, Required amount of water = 0.5 X 50 kg = 25 litres / 50 kg cement bag. For Design mix, the W/C Ratio will depend upon the workability, strength requirements. In IS 10262-2009 ANNEX A. they have explained the process for design mix. Hope that helps you. Water Cement Ratio Test We hope now you have a fair amount of knowledge on Water Cement ratio. It is time to test this vital task. How to test water cement ratio? We actually use Concrete Slump Test at the site level to check this workability & Consistency

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Calculation of Water Cement Quantity for Concrete

  1. As you can see from the Chart, the W/C ratio varies from 0.4 to 0.7 depending on exposure conditions.
  2. If we need to calculate Water quantity for concrete, first find the cement content for the volume.
  3. If we Assume the required cement volume as 50kg,
  4. The required amount of water = W/C Ratio x Cement Volume
  5. Therefore, Required amount of water = 0.45 x 50 kg = 22.50 litres / 50 kg cement bag.
  6. For the Design mix, the W/C ratio will depend upon the workability, strength requirements.
  7. In IS 10262-2009 Annex-A, they have explained the process for the design mix.

Short Note

Water Cement Ratio

The water to cement ratio is calculated by dividing the water in one cubic yard of the mix ( in pounds) by the cement in the mix (in pounds). So if one cubic yard of the mix has 235 pounds of water and 470 pounds of cement– the mix is a. 50 water to cement ratio.

Water Cement Ratio Calculation Example

The water to cement ratio is calculated by dividing the water in one cubic yard of the mix ( in pounds) by the cement in the mix (in pounds). So if one cubic yard of the mix has 235 pounds of water and 470 pounds of cement– the mix is a 50 water to cement ratio.

Formula to Water Ratio

Concentrated formulas are mixed 1:1 with water. Ready-to-feed formulas do not need any added water. Powdered formulas are mixed 2 ounces (60 mL) of water per each level scoop of powder. Never add extra water because dilute formula can cause a seizure.

Concrete to Water Ratio

A properly designed mixture possesses the desired workability for the fresh concrete and the required durability and strength for the hardened concrete. Typically, a mix is about 10 to 15 percent cement, 60 to 75 percent aggregate, and 15 to 20 percent water.

Water to Weight Ratio

To calculate how much water you should drink daily to maintain a healthy amount of water in your body, divide your weight in pounds by 2 and drink that amount in ounces. For example, a 180-pound person should aim for 90 ounces of water, or about seven to eight 12-ounce glasses, each day.

Water Cement Ratio Calculation

The water to cement ratio is calculated by dividing the water in one cubic yard of the mix ( in pounds) by the cement in the mix (in pounds). So if one cubic yard of the mix has 235 pounds of water and 470 pounds of cement– the mix is a. 50 water to cement ratio.

2 thoughts on “What Is Water Cement Ratio | Water-Cement Ratio and Concrete Strength | Role of Water in Concrete”

  1. Sir I need you advice/ guidance for carrying out renovation of my toilet which is situated on the ground floor.The civil contractor has suggested brick bat coba for water proofing after excavating the existing floor tiles .As brick bat coba is time consuming and on reading your articles on micro concrete could I use micro concrete for water proofing of the toilet floor instead of the conventional method of brick bat coba.if I could use micro concrete do provide the correct methodology to be adopted for application along with the time for curring.Looking forward to your valuable inputs.

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