Cement:- The cement is defined as the binding medium in concrete which has both cohesive and adhesive property. This is obtained by pulverizing the clinkers. Clinkers are obtained by a burning mixture of calcareous argillaceous group material in definite proportion. In this article, I am going to tell about ” laboratory procedure of setting time of setting ordinary Portland cement” so I hope you will get full knowledge about it.
So let’s move the laboratory procedure of the setting time of OPC cement.
The exhaustive tests are carried out in the laboratory to decide precisely the quality of cement. Extreme care should be taken to collect a sample of cement. In order to make a representative sample, this is desirable to collect in nearly equal to portions.
Following are the standard test of cement.
1) Chemical composition:- The various tests are carried out to determine chemical constituents of cement. Following are the required for the chemical composition.
- The ratio of the percentage of alumina iron oxide is not less than 0.66
- The ratio of percentage of lime, alumina iron oxide and silica is called lime saturation factor and it is not less than 0.66 and not greater than 1.02
- Total loss of ignition is not greater than 4 percent.
- The sulphur content is so3 and is not greater than 2.75%.
- Weight of insoluble residue is not greater than 1.5%.
- Weight if magnesia is not exceeded 5%.
2) Fineness:- On this test carried to a check proper grinding of cement. A Fineness of cement particle may be determined by sieve test or permeability apparatus test.
3) Compressive strength test:- On this test is carried out a determine the compressive strength of cement. Following is the process;
- A mortar of cement and sand is prepared.
- Water is added to the mortar.
- Mortar is placed in moulds.
- It is a compacted in a vibrating machine for 2 minutes.
- It placed in a damp cabin for 24 hours.
- A specimen is removed to the moulds and they have submerged in clean water for submerged.
4) Tensile strength:- on this test are formerly used to have an indirect indication of the compressive test of cement. This is at per cent generally used to the rapid hardening cement.
- A mortar of cement sand is prepared.
- Water is added to the mortar.
- Mortar is placed in briquette moulds.
- Briquettes are kept in the damp cabin for 24 hours.
- Briquettes are carefully removed from the moulds and they have submerged in clean water for curing.
5) Consistency test:- A purpose of this test is to determine the percentage of water required for preparing cement pastes for another test. Following process are as;
- To take 300gm of cement and added 30% by weight or 90gm of water it.
- To mix water and cement on a non-porous surface.
- To fill the Vicat apparatus.
- A plunger is attached to a movable rod of Vicat apparatus.
- A settlement of plunger is noted.
6) Setting times test:- On this test is used to detect the deterioration of cement due to storage. This may, however, be noted that it is purely a conventional type of test and this has got to no relational with the setting. A test is carried out a find out the initial setting time and final setting time.
7) Soundness test:- A purpose of its test is a detect a percentage of uncombined lime of cement. It test is doing with the help of Le chatelier apparatus test. Following are process as;
- A cement paste is prepared.
- A mould is placed on a glass plate and this is filled by cement paste.
- This is covered at the top by another glass plate.
- A distance between the points of the indicator is noted.
- A mould is removed from the water and this is allowed to cool down.
- A distance between the points of the indicator is an again measured.
So, friends, I hope this article about ” procedure of laboratory test of OPC cement ” remains help for you.