Compressive Strength Test of Concrete

Understanding the compressive strength of concrete, one of the most prominent building materials.

Aim:

This experiment aims to determine the compressive strength of concrete by conducting a compressive strength test.

Theory:

Concrete is a widely used construction material which is known for its strength and durability. The compressive strength of concrete is one of its most prominent properties, as it determines its ability to withstand compressive loads.

Compressive strength is defined as the maximum compressive strength that a material can withstand before cracking or breaking. The compressive strength of concrete is determined by testing a concrete cylinder under axial compression.

Apparatus and materials required

The following apparatus and materials are required to conduct the compressive strength test of concrete.

1. Compressive testing machine
2. Concrete cylinders of standard dimension
3. Tamping rod
4. Steel plate
5. Measuring cylinder
6. Water
7. Weighing balance

Procedure

1. First of all, collect all the required materials and apparatus.

2. Prepare the concrete mixture by mixing cement, sand, aggregate, and water in the required proportions.
3. Pour the concrete mixture into the moulds and compact it with the help of a tamping rod.
4. Level the surface of the concrete with a steel plate and place it in a curing tank, and leave it undisturbed for 28 days.
5. After 28 days, remove the cylinder from the curing tank and wipe off any excess moisture accumulation.
6. Place the cylinder on the compressive testing machine and align it accurately.
7. Apply the load slowly and steadily until the concrete cylinder breaks or cracks.
8. Record the maximum load sustained by the concrete cylinder.
9. Repeat the same test with at least 2 more cylinders to get more accurate and reliable data.

Data analysis

The compressive strength of concrete is calculated by dividing the maximum bearable load sustained by the cross-sectional area of the cylinder. The formula for calculating the compressive strength is as follows:

Compressive strength (N/mm²) = maximum load (N) / cross-sectional area (mm²)

Discussion

The compressive strength of concrete is an important factor in determining the suitability of concrete for its use in construction purposes. The compressive strength of concrete is influenced by several factors, such as the quality of materials used, mix design,

and curing conditions. The compressive strength test is a standard test that is used to determine the compressive strength of concrete. 

Result

The compressive strength of concrete is expressed in N/mm². The average compressive strength of the concrete can be calculated as the average of the compressive strengths of the three cylinders combined. 

Precautions

Some certain measures and precautions need to be taken while performing the compressive strength test of concrete. They are as follows:

1. Only high-quality materials should be used for the concrete mix.
2. Ensure that the moulds are clean and free from debris.
3. Compact the concrete mix properly to avoid any air voids.
4. The concrete cylinders should be handled carefully to avoid any damage.
5. Apply the load slowly and gradually while conducting the compressive strength test.
6. Conduct the test in a safe and controlled environment.

Conclusion

The compressive strength test is a crucial test for determining the strength of concrete. Based on the test results, you can be sure that the concrete used in construction meets the required strength standards.

The compressive strength of concrete can be improved by using quality materials, proper mixing, and curing. The results of the compressive strength test must be compared with the design strength of the concrete to determine its suitability for construction.