How Is Concrete Made?
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. When aggregate is mixed with dry cement and water, the mixture forms a fluid slurry that is easily poured and moulded into shape.
What Is a Concrete
Concrete is widely used building material all over the world in the Construction Industry. Concrete is defined as the uniform mixture of cement, fine aggregate, coarse aggregate and water in the appropriate proportion which will set hardened and acquire the strength after a particular period.
Concrete is a composite material which is made by the mixture of cement, aggregate, and water in the appropriate proportion. In this article, you will get to know all about concrete and Concrete Ingredients and how concrete is made.
Concrete is a site-made construction material unlike other materials of construction and as such can vary to a very great extent in its quality, properties and performance. materials of varying properties, to make concrete for making concrete of good quality the intimate knowledge of the different ingredients of concrete is necessary.
To achieve a strong and durable concrete the careful proportioning and mixing of the ingredients is required. A concrete mixture which does not have enough paste to fill all the voids between the aggregates it will be not possible to place and compact the concrete properly. A mixture with an excess of cement paste will be easy to place and will produce a smooth surface.
To make the concrete durable and achieve the maximum strength it is necessary that there should be proper proportioning and mixing of the Concrete should be done. The quality of the paste determines the characteristics of the concrete. The strength of the concrete depends on the ratio of water to cement. The water-cement ratio is the weight of the water by the weight of the cement.
High-quality concrete is produced by lowering the water-cement ratio as much as possible without reducing the workability of fresh concrete and allowing it to be properly placed, compacted and cured.
Components of Concrete:
There are mainly three basic components which are used to make the concrete mix
- Cement
- Aggregate
- Water
#1. Cement-
Cement is one of the most common and widely used for making concrete. The Cement acts as a binder and the substance which is used for the Construction that hardened, sets, and adhered to the other materials. Cement is initially in the powdered form, it acts as a binder after adding water in it.
#2. Aggregate-
The construction material which is used for the manufacturing of concrete is known as aggregate. Aggregate provides the concrete with its body and strength and mainly act as a filler material to give the homogeneous mass of the concrete along with the cement paste.
Aggregates are also the most important component of concrete. Aggregates give body to the concrete and reduce the shrinkage in Concrete. Aggregate acquire 70% to 80% of the concrete volume. The surface texture of the aggregate may be smooth or rough. Rounded aggregate with a smooth surface will require less cement paste and it will increase the yield per bag.
So it is recommended that to prefer rough texture aggregate as compared to smooth texture aggregate.
#3. Water-
Water is one of the most important ingredients of the Concrete. The water is added to the dry mix due to which cement gains it’s strength through a chemical reaction between cement and water which is known as the heat of hydration. Initially, water is in the dry powdered form. It doesn’t have a bonding Property. The cement acts as a bonding agent only after adding water to it.
Thumb Rule for checking the suitability of water for making concrete is that it should be potable. The water with the maximum amount of salt present in it cannot be used for making concrete. Seawater should not be used in the concreting activity because if contains Sodium and potassium salts. This salt can corrode the reinforcement and cause the failure of the structure.
How to Mix Concrete?
The concreting operation consists of measuring the ingredients of the concrete and mixing them properly to achieve a homogeneous uniform mixture of the Concrete.
- First upon taking all the ingredients required for Concrete such as coarse aggregates and fine aggregate and cement as per the required proportion.
- Make a proper dry mix of the concrete by proper mixing.
- Add a little amount of water at the center of the dry mix.
- Mix it properly and add water gradually in the dry mix so it will achieve proper consistency.
- Mix it with the help of a shovel so that uniform concrete is made.
Necessity of Supervision During Concrete Mixing
- It is very necessary to supervise the concrete operation by the technical person.
- It will help for proper mixing of concrete ingredients in the right proportion.
- It will help to maintain the water-cement ratio which will help to achieve target strength.
- Supervision of concrete will help to achieve a good quality of concrete as the finished product.
Frequently Asked Questions (FAQ) about Concrete
What is concrete?
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. It is a widely used building material in the construction industry.
What are the main components of concrete?
The main components of concrete are:
- Cement: Acts as a binder and provides strength to the concrete.
- Aggregate: Provides the concrete with its body and strength, acting as a filler material.
- Water: Reacts with the cement to form a paste that binds the aggregates together.
How does the water-cement ratio affect the strength of concrete?
The strength of the concrete depends on the ratio of water to cement. Lowering the water-cement ratio as much as possible without reducing the workability of fresh concrete results in high-quality concrete. This ratio determines the characteristics and strength of the concrete.
Why is supervision necessary during concrete mixing?
Supervision by a technical person ensures the proper mixing of concrete ingredients in the right proportion, maintaining the water-cement ratio, and achieving the target strength. It helps produce a good quality finished product.
What is the importance of aggregate in concrete?
Aggregate gives body to the concrete, reduces shrinkage, and provides strength. It accounts for 70% to 80% of the concrete volume. The surface texture of the aggregate can affect the amount of cement paste required and the overall yield of the concrete mix.
Can seawater be used in concrete mixing?
No, seawater should not be used in concrete mixing because it contains sodium and potassium salts, which can corrode reinforcement and cause structural failure.
How is concrete mixed properly?
To mix concrete properly:
- Measure the required ingredients (cement, coarse and fine aggregates) in the correct proportion.
- Create a dry mix by thoroughly mixing these ingredients.
- Gradually add water to the dry mix, starting with a small amount and mixing thoroughly until the desired consistency is achieved.
- Use a shovel to ensure the concrete is uniformly mixed.
What is the role of cement in concrete?
Cement acts as a binder, setting, hardening, and adhering to other materials to form a strong and durable structure. It is initially in powdered form and gains bonding properties when mixed with water.
How does water contribute to the concrete mix?
Water initiates the chemical reaction with cement, known as the heat of hydration, which allows the cement to act as a bonding agent. The water must be potable and free from excessive salts to prevent corrosion and structural issues.
What are the steps involved in the concreting operation?
The concreting operation involves:
- Measuring the ingredients (cement, aggregates, and water) accurately.
- Mixing the dry ingredients thoroughly.
- Adding water gradually and mixing until a uniform and consistent mixture is achieved.
- Ensuring proper supervision during the mixing process to maintain quality and achieve the desired strength.
Why is the quality of the paste important in concrete?
The quality of the paste (cement and water mixture) determines the characteristics and strength of the concrete. Proper proportioning and mixing of the paste ensure the concrete is durable and achieves maximum strength.
