Well, which of us did not calculate the amount of cement during construction or repair? It is difficult to calculate everything down to a kilogram. Therefore, cement often remains and hides somewhere in a barn or on a balcony until better times.
If you do not ensure proper storage, do not monitor the integrity of the bags, moisture will get into the cement. Some, in order not to throw out the hardened material, crush it and mix it with a new solution. Today I decided to raise the topic of using spoiled cement. Is it possible to do this and how will it end?
Why does cement harden?
When cement changes from a loose state to a solid state, the process of hydration proceeds. Those. water and cement molecules combine. Simply put, water enters the material bag and mixing begins.
- First, the molecules seize, forming crystal lattices. It takes about 6 hours. Heat is released during the reaction. Moreover, the reactions proceed the faster, the higher the temperature in the room. Also, their speed is affected by the amount of water that got into the bag.
- When the setting is completed, the mortar begins to harden. Those. he is gaining strength. This stage lasts much longer - up to a month.
If hardened cement is crushed and combined with fresh mortar, nothing will happen. Think about what will happen to the plaster if water gets on it? Nothing! The situation is similar with hardened cement. It is impossible to make a liquid solution from a piece of stone. The old solution will not provide the hydration process, i.e. the binder will not be strong.
How long is the cement and is this period of particular importance?
The manufacturer sets an immediate expiration date for their product. As a rule, for popular brands, the term is as follows:
- cement M600 is good for 3 months;
- cement M400 and M500 is good for six months;
- cements M300, M200 and M100 are good for a year.
Please note that this is only true if you properly store the cement. If you leave the bag open, the material will become unusable after 1.5 - 2 months.
If you mix a mortar from expired cement, it is not as scary as using a hardened material. Nevertheless, the solution will turn out to be of poor quality, lumps form in it, which are very inconvenient to work with.
Cement storage rules
If you want cement to be stored longer and retain its properties, follow these rules:
- 1. When purchasing cement, carefully inspect the bags. They must be sealed.
- 2. Cement is sold in paper bags. This is indicated in GOST, however, such bags do not protect the material from moisture. They are easy to tear, pierce, etc. If you notice that the bag is damaged, pour the material into a whole and strong plastic bag.
- 3. Do not store bags of cement on bare floors or cold ground. They must be placed on wooden pallets at least 30 cm above the ground. Pallets can be additionally covered with foil. The main thing is to leave air flow to the bags.
- 4. Bags need to be rotated periodically, at least once a month or two. Otherwise, the material may shrink.
- 5. If you have leftover cement of different brands, store them separately from each other.
What to do with damaged material?
I think it is already clear that grinding hardened cement and putting it into action is not the best idea. But do not rush to throw away damaged material. It can still be useful in the household. For example, you can use cement for filling holes, for backfilling, as an aggregate when concreting not very important structures.
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