Advantages and Disadvantages of Concrete

Cement, sand, and small stones (aggregate) are combined with water to create the construction material known as concrete. This fluid mixture gradually solidifies and hardens. Studying concrete and its real-world applications and characteristics is necessary for understanding concrete. In the construction of buildings, concrete is used to construct foundations, columns, beams, slabs, and other load-bearing structures. Concrete may be moulded into any shape because it is wet at the time.

Buildings and other structures are now constructed using a variety of concrete kinds. They possess unique traits and qualities. Small residences will be constructed using regular concrete, whereas larger structures will be constructed using high-grade concrete. For the construction of roads, coal tar (bitumen), which is heated and combined in place of cement, is used to create asphalt concrete.

Grade of concrete

To achieve the necessary strength, cement, sand, and stone are mixed in a precise ratio. This is referred to as the concrete grade. The strength of various concrete mix types is designated as M5, M10, M15, or M20, where M stands for the mix and 5, 10, 15, or 20 refers to the strength in kN/m². As an illustration, the mix ratio for the M15 grade is 1: 2: 4, where 1 is the cement ratio, 2 is the sand ratio, and 4 is the stone ratio.

Types of concrete:

• M5 Concrete (1 : 4 : 8)
• M10 Concrete (1 : 3 : 6)
• M15 Concrete (1 : 2 : 4)
• M20 Concrete (1 : 1.5 : 3)
• M25 Concrete (1 : 1 : 2)
• M30 Concrete (1 : 0.75 : 1.5)

For simple structures, M15 and M20 concrete is typically utilized. However, M25 and other types of concrete are used for multi-story structures. Concrete must have a sufficient water-to-cement ratio in order to be usable. The water-cement ratio is 0.6, meaning that one bag of cement weighs 50 kg, or 30 litres, of water. Therefore, one cement bag requires 30 litres of water.

Types of concrete by construction

1. Plain Concrete

PCC, or plain concrete, is utilised for general construction projects. The mix design in this case is 1:2:4 or 1:3:6, which will produce typical strength. In PCC, iron rods are not utilised. This kind of concrete is primarily used to build sidewalks, streets, and straightforward structures.

2. Reinforced Concrete

It is referred to as RCC concrete. RCC uses a minimum M20 grade or a 1:1.5:3 combination. This involved the use of iron rods that varied in thickness. Tensile-strength bearing structures are built with this kind of concrete. For instance, a column, a roof, or a beam.

3. Asphalt Concrete

A typical composite material used for parking lots, airports, and roadways is asphalt concrete. It is created by heating stone, sand, and coal tar (bitumen). A hot mix plant is utilized for this.

4. Prestressed Concrete

In big projects, prestressed concrete units are used. The tendons used in concrete are prestressed using a unique way before the service load is really applied. These days, this method is used to create bridge spans and other components.

5. Precast Concrete

As needed, different structural units are created at the factory and transported to the site to be used. Precast concrete refers to these concrete components. For instance, precast walls, staircases, and concrete blocks.

6. Lightweight Concrete

Concrete is categorized as lightweight concrete if its density is less than 1920 kg/m³. Sandstone is a key component of aggregate that increases the density of concrete. Pumice stone, perlite, and scoria are a few examples of lightweight aggregates. For example, it is employed in the construction of long span bridge decks.

7. High-Density Concrete

High density concrete is defined as having a density between 3,000 and 4,000 kg/m³. Heavy weight aggregate is utilized here. Nuclear power plants and other related construction projects employ this kind of concrete.

8. Ready Mix Concrete

Ready mix concrete is the name given to the concrete created in the mixer machine. A transit mixer mounted on a truck is used to transport the ready-mixed concrete to the job site. Once there, it can be used right away.

How to make concrete

There are two types of concrete. Normal mix is the first category, while tailored mix is the second. The mix ratio of 1:2:4 is frequently employed for small residential constructions. The most typical ratio is this one. Concrete design mix proportions are created using data from experiments conducted in various laboratories.To obtain the necessary strength in accordance with the structural design, testing is carried out in laboratories using materials that are readily accessible locally.

The procedure in question is known as concrete mix design. The right elements are combined in the chosen amounts after the ratios are known. Mixing may take many different forms. Hand mixing, machine mixing, or batching plant. For quality, the relevant alternative is chosen. Each component is placed on a level surface and manually combined with a shovel when mixing by hand. Machine mixing employs a variety of machine types. How used concrete is converted into new concrete:

The concrete is transported to the casting location and poured into the formwork once it has been well mixed. It takes concrete a certain period of time to become strong enough.

To make up for the moisture lost owing to evaporation, threshing is done using a variety of techniques once the formwork has been removed. The hydration process, which is in charge of setting and strengthening, needs moisture to function. As a result, this procedure is continued for at least 7 days after the formwork has been removed.

Difference between concrete and cement

When someone says "cement wall" or "cement road," they frequently mean "concrete." Although both cement and concrete are used as building materials, they are not the same. That combination, known as concrete, contains cement. Lime and silica are used to make cement. About 85% of cement is made up of these two ingredients. In addition to this, it may contain calcium, iron, aluminum, and other substances.

This combination is heated to a high temperature and combined in big furnaces (about 2,700 to 3,000 degrees Fahrenheit). Clinker is the product that is created as a result of this. Clinker is available in little pills. Gypsum is added to the powder made from these crushed pills. This is concrete. When water is added to cement, a chemical reaction occurs, and the mixture then dries and hardens. Actually, cement holds things together.

There are also two sorts of cement. One is hydraulic, and the other is not. Water aids in the hydraulic cement's hardening process. Once it hardens, water's influence on it is ultimately reversed. Such cement is helpful in areas with ample water supply. When water is added to non-hydraulic cement, it does not harden. Portland or Ordinary Portland Cement is the name of a widely used cement. It is a type of hydraulic cement used in building construction. Joseph Aspdeen of Britain constructed it in the 18th century.

In this area, cement comes in a wide variety. Cement, water, and other materials like gravel, sand, and stones are all combined to create concrete. Their availability varies depending on the demand. Due to its capacity to maintain rigidity, concrete is the most often used construction material worldwide.

Ready mix concrete

In factories or batching plants, ready mix concrete is a form of mixed concrete that is produced in accordance with predetermined standards. A truck-mounted transit mixer carrying the final concrete mix is delivered to the construction site. Concrete that has been manufactured in a factory and is ready-mixed ensures a high level of proficiency and stability. The utilized aggregates, such as sand, stone, etc., are washed to eliminate the dust and grime to enhance the quality of Ready Mix Concrete (RMC).

Due to the fact that ready mix concrete is made by professionals using practical conditions, it is stronger and more durable than regular concrete. Additionally, it offers concrete in all classes, including M15, M20, and even higher grades. It is produced by a number of businesses. For usage on a building site, it is produced as a unit per cubic meter. Approximately, 6 cubic meters of concrete may be held in a transit mixer.

Advantages of concrete

• Concrete that has just been compacted may be shaped into any shape needed.
• Environments like sunshine, rain, moisture, wind, etc. have no effect on concrete.
• Pests like termites, dampness, and rust have no effect on it.
• Concrete has a very high compressive strength.
• Concrete is strong and brittle.
• When all of its attributes are considered, it is a frugal one.
• Because extremely high workability concrete can be pumped very simply, it can be installed in places where concrete cannot be.
• Concrete is a man-made building material that may be shaped to suit its purpose.

Disadvantages of concrete

• The tensile strength of concrete is very low i.e. the tensile strength is only 10% of the compressive strength.
• Cement concrete is not completely impermeable
• Concrete is a heavy material and due to which its self-weight becomes very high.
• Fresh name concrete shrinks on drying and expands when it comes in contact with moisture, due to which it starts cracking and to prevent this, provision of contraction joints has to be made.
• Hardened concrete is a hard material, it expands due to temperature changes, due to which there is a possibility of cracks in it. To prevent this, a provision for expansion joint has to be made in it.