# Casting and Testing of concrete cubes

Design the concrete to get the optimum quantity of each ingredients for concrete. In the previous blog I have already discussed about the complete designing procedure of concrete as per Indian standards. Though it is very important to also check whether the designed mix is of the desired strength. In this blog I will be explaining the complete procedure on how to do casting of the concrete cubes as per Indian standards.

The standard size of cube is 150 mm. Calculate the total quantity of concrete required for casting 9 sample cubes.

Check this post to know how to calculate the quantity of concrete.

### Steps to be followed for casting of a concrete cube

1. Clean the surfaces of the mould and apply grease on all the 9 moulds for lubrication.
2. Fill the concrete in each mould in three layers.
3. After each layer do proper compaction by applying 35 strokes using a tamping rod.
4. After 3 rd layer compaction, Finish the top surface using a flat trowel.
5. Leave the specimen for 24 hours, undisturbed.
6. After 24 hours, remove the specimen from mould.
7. Next very important step is to mark each specimen, write the date of casting and give the specimen number.
8. For curing, immerse all the concrete specimens inside a water tank.

### Steps for testing of a concrete cube

1. After 7 days, we have to test 3 concrete cubes.
2. First take out the 3 specimens from the tank and let dry the surface of cubes.
3. Note down the date of casting and the specimen number for a proper data management.
4. Place the concrete cube in the Universal Testing Machine (UTM).
5. The specimen should be placed in such a way that the direction of casting should be perpendicular to the direction of load application.
6. Start applying the load, from the UTM till the specimen fails.
7. Record the maximum load from the UTM.
8. Calculate the compressive strength using the formula:
• Compressive strength = Maximum load / Cross sectional area of specimen
9. Similarly follow the same steps for all the three specimen and the total compressive strength will be the average strength.
10. After 14 days and 28 days you have to do the same set of steps (2-9) to calculate the concrete strength.

This way you can check whether the concrete mix ratio is giving you the desired compressive strength. If you fail to get the desired strength then you need to alter the parameters and again do the concrete mix design.

## Concrete Mix Design

• Calculate cement, sand and aggregate quantity in concrete.
• Calculate the number of premix bags required for your project.
• Option to set your own size and rate of premix bags.
• Calculate the volume of concrete required for slabs, walls, footings and columns.
• Calculate the weight of ingredients required for preparing the calculated volume of concrete.