Object: To Determine the Compressive Strength of a concrete cube.
Apparatus:
- Universal Testing Machine,
- Cube Mould for Casting,
- Physical Balance.
Material:
Concrete Cube (Dimensions __________________)
Theory:
- To cast concrete cube in laboratory.
- To remove the mould and immerse the cube in drinking water for 28 days.
- Take out the cube from water after 28 days.
- Let cube to get dry for few hours.
- Once the surface of cube is dry, take the weight of the cube in order to know the density of concrete. Now it is ready for test.
Procedure:
- Put the concrete cube into Universal testing machine.
- Before starting of real test put the load option to Zero, which means you are testing a fresh cube. Also switch on the machine in Max: Peak Hold position so that maximum load reading must be recorded otherwise you will loose the maximum peak load once cube breaks.
- Close the safety guard on to avoid any accident
- Apply the load into small increments, say 10KN per minute. If load is being applied in slow manner it is resemblance of real static load of the structure.
- Best mix of the failure will give pyramid failure surface.
Observation and Calculations:
- Weight of the Cube in Kg.
- Ultimate load when cube fails and Machine Console gives you the maximum peak hold in N.
- Cube is in state of complete collapse through cracking and crushing.
- Machine may give you a loud thud at the time of failure.
Result:
- Density of concrete _________
- Ultimate Strength, which is called here as Cubical Strength in (Load/Area in sq. mm) _________.