Cement clumping


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Old 05-18-06, 09:33 AM
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Red face Cement clumping

I buy cement by the pallet, but sometimes it takes a couple of weeks to use it all. In humid weather, however it tends to get clumpy and needs to be sifted. Has it lost any of its strength do to the clumping?
 
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Old 05-18-06, 10:10 AM
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Cement is hydrophillic. It attracts and absorbs moisture from the air. If you remove the clumps, no loss of strength.
 
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Old 05-18-06, 10:58 AM
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Cement clumping

Often much of the "clumping" is not due to any hardening or chemical reaction, but due to compaction under pressure, which breaks up in a mixer. Mositure and proper mixing times break down this type of clump. This may be most evident in the corners of the bags.

If the bags are not open or punctured, they are usually moistureproof. A good supplier/dealer of cement will deliver cement with a poly cover that can be slipped over the pallet after bags are removed.

Take a look look at the clumps and see what happen a few minutes after you add water before you through the trouble and mess of screening an entire bag or two.

Dick
 
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Old 05-18-06, 04:22 PM
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Clumping is usually a different issue than being packed. Packed bags should be "boxed", i.e. rolled, and they are fine to use, but clumping is indicative of old/moisture exposed cement.

Portland/masonry cement bags are not usually plastic lined like consumer cementious bagged products such as mortar mix or concrete mix. Poly bagging cementious products in a covered warehouse is usually counter productive as it traps moisture and creates condensation.

As a supplier, we do want to have portland/masonry in the warehouse for any longer than a week, and seldom have it for longer than a couple of days.
 
 

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