The cubes should be placed correctly on the machine plate (check the circle marks on the machine).

Now place the concrete cubes into the testing machine.

The Cube weight should not be less than 8.1 Kgs.

The specimen should be in dry condition before conducting the testing.

The specimen should be removed from the water 30 minutes prior to the testing.

Every 7 days the water should be renewed. The specimen should be kept for 7 or 28 days.

Keep the specimen submerged under fresh water at 27 ° Celsius.

After 24 hours remove the specimen from the mould.

After some time the mould should be covered with red gunny bag and put undisturbed for 24 hours at a temperature of 27 ° Celsius ± 2.

Finish the top of the concrete by trowel & tapped well till the cement slurry comes to the top of the cubes.

Fill the concrete to the mould with the help of vibrator for thorough compaction.

Add design quantity of water to the dry proportion ( water-cement ratio) and mix well to obtain uniform texture.

Thoroughly mix the dry ingredients to obtain the uniform mixture.

The Ingredients should be sufficient enough to cast test cubes

Measure the dry proportion of ingredients (Cement, Sand & Coarse Aggregate) as per the design requirements.

To find compressive strength value of concrete cubes.

Specified characteristic compressive strength (N/mm2) at 28 daysĬompressive Strength of Concrete Lab Test Objective Minimum compressive strength N/mm2 at 7 days If the concrete fails at 14 days, then we will reject that batching.Ĭompressive Strength Table of Concrete at 7 & 28 Days Grade of Concrete So at sites, we do normally test concrete at this interval. Once it attains certain strength at 7 days, then we know (according to the table) only 9% of strength going to increase. So we can’t predict the strength until the concrete comes to that stable state. Concrete Strength Overtime Days after CastingĪs you can see the concrete gains its strength rapidly til 7 th & 14 th Days. Concrete is a macro content with Sand, Cement, & Coarse aggregate as its micro-ingredient (Mix Ratio) and gains its 100% strength over time at the hardened state.

7 days to die concrete pillar 50