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**✔ **The ratio of the weight of water to the weight of cement is a water-cement ratio.

**Mathematically,**

**Water cement ratio = **(Weight of water in liters) / ( Weight of cement in kg)

**✔ **Concrete’s full hydration usually requires approximately 38% water.

**A. What is the Water Cement Ratio For M25 Concrete? **

** ✔ As per IS 10262:2019,** The water cement ratio for M25 concrete is 0.45.

Concrete Grade | Recommended Water-Cement Ratio |
---|---|

M10 | 0.6 |

M15 | 0.55 |

M20 | 0.5 |

M25 | 0.45 |

When 2% plasticizers or superplasticizers are used in high-quality concrete: **Commonly 0.35 to 0.40 w/c is used. **

**( Note: **Plasticizers or superplasticizers can increase the flowability and workability of higher-strength concrete.

Mix design is suggested rather than nominal mix if Plasticizers or superplasticizers are used to determine the exact suitable water-cement ratio.**)**

**✔ **Example:

If you want to make M25 concrete with a water cement ratio of 0.45 using 50 kg of cement, how much water do you need to mix the Concrete?

**soln;**

**Required amount of water ( in liters) = w/c ratio × weight of cement in kg **

= 0.45 * 50

= 22.5 kg

= 22.5 L

( 1 kg is equivalent to 1 L )

**B. What Happens When Water is not Properly Proportioned with Cement? **

**✔ **When the amount of water used in concrete increases, the cement paste becomes more diluted, resulting in more voids once the water molecules evaporate. These voids can cause various issues, such as cracking, shrinkage, flexural failure, and changes in color due to imbalances in strength and **porosity**.

**✔ **Conversely, insufficient water usage can impede the proper binding of the materials and weaken the Concrete’s overall strength.

Read Also: Grades of Concrete |

Verified Article By Er. Madhu Krishna Poudel |