What is water-cement ratio? What is its effect on concrete?

What is water-cement ratio?

The water-cement ratio (W/C ratio) is a fundamental parameter in the production of concrete, representing the ratio of water to cement in the mixture. It is defined as the weight of water divided by the weight of cement in the mixture, expressed as a decimal value between 0 and 1. For example, a W/C ratio of 0.4 means that 400 grams of water are used per 1000 grams of cement.

Effect on Concrete

The W/C ratio has a significant impact on the properties and performance of concrete. The following are some of the key effects of W/C ratio on concrete:

1. Workability: A higher W/C ratio generally improves the workability of fresh concrete, making it easier to place and finish. However, excessive water can lead to reduced strength and durability.
2. Strength: A lower W/C ratio generally results in higher strength concrete, as the reduced water content allows for better hydration and cement bonding. However, a W/C ratio too low can lead to reduced workability and poor placement.
3. Durability: Excessive water in the concrete can lead to reduced durability due to increased porosity and susceptibility to water ingress.
4. Shrinkage: A higher W/C ratio can result in increased shrinkage, which can lead to cracking and reduced durability.
5. Cost: A higher W/C ratio generally increases the cost of concrete, as more water is required.

References

1. ACI (American Concrete Institute) (2014). ACI 211.1-14: “Minimum Requirements for Concrete Mix Design.” Farmington Hills, MI: American Concrete Institute.
2. EN (European Norm) (2013). EN 206-1: “Concrete – Part 1: Specification, performance, production and conformity.” Brussels, Belgium: European Committee for Standardization.
3. MS (British Standard) (2018). BS 8500-2: “Concrete. Part 2: Specification for concrete.” London, UK: British Standards Institution.

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