Cement mortar is prepared by mixing cement and sand in dry state and then adding required amount of water in it and mixing them thoroughly. The following procedure should be followed to prepare cement mortar by hand mixing.
Procedure for Hand Mixing of Cement Mortar
- Take one bag of cement, which has a volume of nearly 0.035m3.
- Then measure required quantity of dry sand using a box measure. A box has a volume of 0.035m3. For example if you are preparing a cement mortar of the ratio 1:3 (i.e. 1 part cement and 3 parts of sand), then for one bag of cement take 3 boxes of sand.
- First spread the measured amount of sand on a water tight platform or on a steel trough.
- Spread the cement over the sand.
- Then mix them dry by turning over & over, backward & forward several times by a shovel, till the mixture looks uniform in colour.
- Out of this dry cement & sand mix, take out only that amount of mix which can be used within 30 minutes, and form it into a heap.
- Make a small depression on top of the heap.
- Add required amount of water so as to give it required consistency, to the center of the heap.
- Mix the whole mass thoroughly for 5 to 10 minutes by means of a shovel.
- Water of amount 70% of weight of cement is just sufficient to give it necessary consistency for 1:3 mortar (i.e. Grade M 7.5)