What is the effective storage period of cement?

The effective storage period of cement depends on the actual situation.

If it is stored in a dry environment for about 2 months, the strength will be reduced by about 10 20% after three months, and the longer the time, the more the strength will be reduced.

Cement easily absorbs moisture from the air, undergoes hydration and condenses into lumps, thus losing its cementing ability. Therefore, special attention should be paid to waterproof and moisture-proof cement during storage.

Dry and ventilated environment, half a month.

Valid for 30 days from the factory

The normal shelf life of cement is 3 months. But try to use it within 30 days, after all, the longer the storage date, the worse the performance in all aspects. If the strength is affected, it will be easy to empty the bag or even fall off in the later use, which will be very dangerous, so when using it, it is necessary to control the time.

It is recommended not to buy too much at one time, so as not to waste the situation, to consider the actual situation, you can buy one or two more bags, so as to avoid possible loss during transportation or use.

Cement: powdered hydraulic inorganic cementitious material. After adding water and stirring, it forms a slurry, which can be hardened in air or water, and can firmly cement sand, stone and other materials together.

The shelf life of cement is 3 months.

This time is the relevant industry standard storage time, generally in the packaging of cement bags will be marked its shelf life, if the cement is more than 3 months of shelf life is not used, you need to consider how to use it after the new test, because once there is a deterioration problem, it can only be used in some unimportant temporary projects.

Judgment of the symptoms of cement expiration.

1. It can be judged from the density of cement, if there is agglomeration inside the cement, then it is best not to buy. Because it means that the cement has expired or there is moisture inside, the cement is relatively fine powder under normal circumstances.

2. You can check the cement bag to see if the bag is complete and whether the seal is round and sealed. If it is sealed, it means that the cement has not been opened.

3. Check whether the color of the cement is dark green or dark gray. Most of the cement colors on the market are dark green or dark gray, and the strength of this cement is relatively high, but if the color of the cement is white or yellowish, it means that it is likely to be adulterated, and the cement with low hardness is not suitable for building decoration.

Generally, it is stipulated that the cement should be stored for three months, and it should be used by one lower grade. However, how long cement can actually be stored depends on the storage conditions, i.e. whether the cement will absorb moisture. Absorbing moisture, the activity of cement will be reduced or even agglomerate, and it cannot be used after agglomeration.

When stored completely dry or in conditions protected from moisture, such as in sealed plastic drums, cement can be stored for more than two years.

Common types of cement: Portland cement, ordinary Portland cement, slag Portland cement, pozzolana Portland cement and fly ash Portland cement.

Technical characteristics of commonly used cement:

1.Setting timeliness: The setting time of cement is divided into initial setting and final setting. The initial setting is the time from the time when the cement is mixed with water and the cement slurry begins to lose its plasticity. The final setting is the time when the cement slurry begins to mix to the time when the cement completely loses plasticity and begins to produce strength.

2.Volume stability: refers to the property of whether the volume changes uniformly in the process of hardening. After the cement hardens, the uneven volume change becomes poor volume stability and cannot be used.

3.Water thermalization: The hydration reaction of cement is an exothermic reaction. As the hydration process progresses, the continuous release of heat is called hydrothermalization. The size of the heat released by water heating and the speed of heat release are mainly related to the cement grade, mineral composition and fineness.

4.Fineness: refers to the thickness of cement particles. The finer the particles, the higher the early strength. However, the finer the particles, the higher the production cost and the susceptibility to moisture failure.

5.Standard consistency water consumption: refers to the water consumption of cement mortar when it reaches the standard consistency. The standard consistency is the consistency specified in the national standard when making cement for stability and setting time.

The normal shelf life of cement is 3 months.

The expiration date of cement is three months. If it is a relatively dry season, it can be stored for 2 to 3 months, and if it is a humid environment and season, then it can be stored for about half a month at most, so we have to store it according to the specific environment.

If the bagged cement is stored for a longer time, its physical properties will be affected and some changes will occur. If it is early in storage, because the change in internal moisture is not very distinct, but the longer it is stored, the more water will be needed. If the coagulation time is very long, it will also have a great impact on the final coagulation time.

Uses of cement

Cement plays a role in concrete, and cement is basically used in other projects such as construction and national defense, that is to say, the buildings we see basically have the existence of cement materials, so it has the ability to make the building achieve a fixed role, so that it can have the effect of earthquake resistance.

Cement is especially suitable for the manufacture of concrete, precast concrete, fair-faced concrete, GRC products, adhesives and other special occasions, widely used in colored pavement bricks, permeable bricks, cultural stones, sculpture crafts, terrazzo, wear-resistant floors, putty, etc., with high light reflection performance, so that the manufacture of curb stones, road signs, road dividers have higher traffic safety performance.

The validity period of cement is generally three months, and the cement that exceeds the validity period is called "expired cement", and the expired cement must be tested and used according to the strength level determined by the test.