Contd. from Part-II….
Storage of cement: Primary purpose of proper & safe storage of cement is to safeguard it from it’s arch-enemy, i.e. moisture.
An efficient storage structure must be a damp proof one, i.e., it’s floors, walls, roofs etc. should be damp or leak proof. All openings, i.e. doors, windows, ventilators etc. should be so constructed as to provide effective tightness against entry of moisture.
Packaging of cement should be done in moisture proof bags and organic fibre bags such as jute bags should be avoided for such purpose. In case of jute bags, the cement should be used as quickly as possible.
The height of cement stacks should be restricted to the height of 10 cement bags and the stacks should be isolated from the floor.
The cement should be stacked closely in order to minimise air circulation and thus moisture. Stacks should also be covered with water proof covers for additional protection from moisture.
If possible, the humidity of the room should be reduced as much as possible.
The stacks should have a clear gap of at least 1 foot from the walls.
Cement should be consumed within 3 months as by then it already looses 15 to 20% of it’s strength.
Visual tests for cement: Visual tests on cement are quite simple and can be performed quickly in construction sites in order to have a superficial idea of some of the it’s physical qualities. These tests are no substitutes for the general laboratory tests that are conducted. If these visual test results are not satisfactory, the cement may not be suitable for any standard work and thus may not be used.
Cement should be free from lumps.
When rubbed between fingers it should feel smooth and not coarse. Roughness indicates impurities/adulteration etc.
Handful of cement sprinkled in still water should sink after a while. Otherwise, it too indicates presence of impurities.
Hand inserted in a bag of cement should feel cold.
Fresh cement paste kept submerged in water for a day should set smoothly without showing any cracks. This is an approxima