Question

Concrete is a mixture of (1) Cement, lime and water (2) Cement, sand and watcr (3) Cement, gravel, sand and water (4) Cement, slaked lime and water

Short answer

Option (3) is correct: cement, gravel, sand, and water.

Step-by-step solution

- Identify the Common Ingredients in Concrete

Concrete typically consists of several key ingredients. These ingredients are cement, aggregates (such as sand and gravel), and water.

- Review Each Option for Correct Ingredients

Examine each given option to see which one includes cement, aggregates (sand and gravel), and water. Option (1) includes lime which is not a common aggregate for concrete. Option (2) lacks gravel. Option (3) includes cement, gravel, sand, and water. Option (4) mentions slaked lime instead of typical aggregates.

- Determine the Correct Option

Based on the review, Option (3) includes all the typical ingredients for concrete: cement, gravel, sand, and water.

Key concepts

cement

Cement is a key ingredient in concrete. It is a binding material that holds the aggregate particles together. When mixed with water, it forms a paste that hardens over time, providing strength and durability to the concrete.
Portland cement is the most common type used in concrete mixtures.
It is composed of limestone, clay, and iron ore. When these materials are heated at high temperatures, they form clinker, which is then ground into a fine powder to create cement.
Once water is added to cement, a chemical reaction called hydration occurs. This process causes the cement to harden and gain strength.
Remember, the right proportion of cement in the mixture is crucial to ensure the concrete's strength and stability.

aggregates

Aggregates are essential components of concrete, providing bulk, strength, and stability to the mixture. They are typically divided into two categories: fine aggregates and coarse aggregates.

Fine aggregates usually consist of natural sand or crushed stone with particles smaller than 4.75 mm.
Coarse aggregates include gravel or crushed stone with particles larger than 4.75 mm.

Both types of aggregates fill the volume in concrete, reducing the amount of cement required and improving the mixture's overall performance.
Proper selection and grading of aggregates are vital to achieve the desired concrete properties, like workability, strength, and durability.

mixture ingredients

Concrete is a versatile construction material made up of several key ingredients: cement, aggregates (sand and gravel), and water. Each of these components plays a crucial role in the overall properties of the concrete mixture:

• Cement: Acts as a binder that holds the aggregate particles together.
• Aggregates: Provide strength, bulk, and stability. They reduce the amount of cement required.
• Water: Triggers the chemical reaction known as hydration, which causes the cement to harden.

In some cases, admixtures are also added to the concrete mixture to enhance specific properties, such as workability, setting time, or durability.
By understanding and carefully controlling the proportions of each ingredient, engineers and builders can create concrete that meets the specific requirements of a wide range of projects.