concrete cube test

How to perform concrete cube test in universal testing machine to determine the compressive strength?

Compressive strength of concrete:

It is nothing but the loads it can carry on its surface without any crack or failure. So here the compressive strength of the concrete is being applied at the point of failure.

We do concrete cube test to determine the compressive strength of concrete.

Concrete has more compressive strength than steel reinforcement. While steel reinforcement has more tension strength than concrete.

Procedure for concrete cube test:

For the concrete cube test two types of specimens used of cube moulds 150mm ×150mm ×150mm and 100mm× 100mm× 100mm depending upon the size of aggregates used.

Generally, 150mm ×150mm ×150mm cube mould specimen used.

Concrete is poured in the mould while we do casting of the structure.

Before the pouring the concrete in the mould with concrete, cube moulds should be free from water and any other unwanted material, and apply the oil in inner surface of the concrete.

Concrete should be filled with three layers of 35 numbers of stocks each layer with the 16mm diameter temping rod.

After the filling in 3 layers, place cube in the cube vibrating table.

After some minutes we write identification of cubes serial number, dates, concrete grade etc details on the cube.

Top surface of the cubes should be smooth as so much for easily writing.

After 24 hours we remove the mould and place the cubes in curing tank which should be at 27+-2 °C.  Make sure water should be fresh and free from any other impurities. Also make sure water changes once in a week.

Cube test we do generally after 7 days, 14 days, 21 days and 28 days. Also, it depends on the client policies.

We place cube serial number wise that is indicated on the cubes in the UTM (Universal testing machine) after dry the cubes for approximately 8 hours.

After placing the cube in UTM we find the compressive strength of concrete. UTM machine indicate two values of the concrete cubes, load (KN) and strength (N/mm2).

UTM machine will apply the load gradually on the cube that we placed, and will go to cubes breaking limit. And that is called compression strength of the concrete.

Now we have to follow the IS code for the results we got as to ensure the cube is passed or failed.

As we can see in the table the cube results come out with its minimum criteria respectively the grade of concrete and number of days, we perform the cube test.

Concrete will gain the strength rapidly after the early ages of casting if we do proper curing of the structure and it changes the rate of gaining strength after the days pass on. Rate of gaining strength is decreased and overall gaining the strength of concrete will increase.

Also, we have to make sure in every cube sample which consists 3 nos of cube should be in 15% variation according to IS code.

Number of samples depends on the quantity of the concrete as shown in the figure.

The average strength of the three cubes will be the strength of the concrete.

This is the procedure and things to take cere of while performing the concrete cube test.

How to perform concrete slump cone test at the site

https://www.onlinecivils.com/2023/07/23/how-to-perform-concrete-slump-cone-test-at-the-site/

What is plum concrete and its uses

https://www.onlinecivils.com/2023/07/13/what-is-plum-concrete-and-its-uses/

Why do we provide steel as reinforcement in concrete structure?https://www.onlinecivils.com/2023/07/12/why-do-we-provide-steel-as-reinforcement-in-concrete-structure/

what is the size of concrete cube moulds?

For the concrete cube test two types of specimens used of cube moulds 150mm ×150mm ×150mm and 100mm× 100mm× 100mm depending upon the size of aggregates used.

Generally, 150mm ×150mm ×150mm cube mould specimen used.

What is the temperature of concrete cube for curing?

After 24 hours of casting the the cube in the cube mould we remove the mould and place the cubes in curing tank which should be at 27+-2 °C.  Make sure water should be fresh and free from any other impurities. Also make sure water changes once in a week.

Post Author: hemantduva

Leave a Reply

Your email address will not be published. Required fields are marked *