BETTER CONSTRUCTION

HOW TO CHOSE BETTER CEMENT

[rahulsharma321-blog1]

Reduction in Cement Strength Due To Storage

1. Due to absorption of moisture by cement during storage, cement retards in hardening and reduces the strength. 2. It is okay for cement to absorb up to 1.2% moisture as this level of moisture is acceptable but if absorption exceeds 5%, the cement is destroyed for all practical purposes. 3. Different types of cements should not be mixed while using them for constructional purposes. 

So in all reason for safety it is most important to have a clearly marked cement bag with all details of manufacturing including date of manufacturing, expiry and batch number.

[rahulsharma321-blog1]

Precautions While Purchasing Cement

Cement is the most important raw material used in a building. You should ensure the quality of ‘Cement’ using the following guidelines.

1. The cement should be factory manufactured instead of plant manufactured. 2. The cement should be packed in the bags of synthetic jute or polypropylene bags. 3. The cement bags should not be hand stitched. 4. The cement bag should bear manufacturer's name or his trade mark on it if any. 5. The cement bag should bear the grade and type of cement. 6. The cement bag consignment must have identification mark on package. 7. The cement bag should indicate the date of manufacturing visibly and correctly in proper print. 8. One cement bag should have 50 Kg. weight. 9. The cement bags should not be older than six weeks from the date of manufacturing. 10. Do not purchase cement bags which are partially set due to moisture. Do not purchase if there are small lumps in the bags. 11. Do not purchase cement bags which are pressed or have lumps due to high pressure of stack having more than 10 to 12 bags. 12. Do not take cement bags which are torn by side and stitched in later.

[rahulsharma321-blog1]

Cement Storage and Handling

Cement has a limited storage life when packed in bags. Always check when they expire.

Bags are vulnerable to water vapour and will absorb moisture if exposed to rain and water. 

Cement is designed to react chemically with water and any exposure to moisture will cause it to set and harden. 

If cement starts to harden in the bags it should be discarded. 

The following building tips will help to prolong the shelf life of cement:

Store on pallets off the floor, preferably on top of plastic sheets

Stack close together to minimise air circulation

Keep the cement store doors and windows closed

Stack away from walls

Cover stacks with plastic sheet

Handle bags carefully and, in order to reduce breakages and dust nuisance, do not walk on bags. In the event of problems with damp cement or excessive bag breakages, do not buy them.

Cements have a shelf life which means they expire. NEVER BUY WITHOUT CHECKING THE EXACT EXPIRY DATE PRINTED CORRECTLY ON THE BAG.

[rahulsharma321-blog1]

Discourage patronage of cement without expiry date.

NEVER buy cement without expiry date.

The expiry date on cement is six months shelf life for bag, while for air-tight container it is one year. But in India no one buys or sells containers.

If you don’t find expiry date on cement, don’t buy it because when you do, if anything happen to your building, you only have yourself to be blamed,” 

The Government should ideally issue an ultimatum to cement manufacturers on product labelling and traceability requirements. Primarily, the guidelines mandate the manufacturers to indicate on product bags the manufacturing and expiry dates, product application information as well as the batch numbers of the products. 

Cement manufacturers, had appealed to review its initially-proposed 30-day deadline to enable them to implement the changes in their processes which later became 90 days.

 The move, which will save cement companies from huge logistic costs , also places a responsibility on cement manufacturers to ensure that their products meet required guidelines and health and safety requirements. 

While processes should be initiated to ensure that products are properly stored by distributors and retailers to avoid compromising product integrity.

Make sure you are being a good citizen by always checking expiry, batch details, manufacturing details before buying bags for your next construction.

it’s for your own safety.

[rahulsharma321-blog1]

Moisture is not good for Cement

Cement is a hygroscopic material meaning that it absorbs moisture In presence of moisture it undergoes chemical reaction termed as hydration. 

Therefore cement remains in good condition as long as it does not come in contact with moisture. 

If cement is more than three months old then it should be tested for its strength before being taken into use.

Always check the date of manufacturing and expiry of the cement before buying and opening the cement bags. 

Best cement bags are the ones that were packed less than 30 days ago.

[rahulsharma321-blog1]

Cement Expires

Bagged cement is not airtight and even if unopened should be used within a 1-2 months. 

Although again, the shelf life of individual bags depends on the conditions under which they have been stored. At best, correctly-stored, unopened bags might have a shelf life of up to 90 Days.

As long as the cement is less than six months old, has no lumps and is a completely free-flowing powder, it should be okay to use for non-structural purposes. All structural jobs (ie. jobs that require maximum strength) should always use fresh cement.