Portland cement is used as a building material in many operations - from pouring foundations and erecting walls to road construction and various repairs. Since the volume of sales of this material is significant, unscrupulous manufacturers also appear who are trying to sell counterfeit products at the price of a quality mixture. It is clear that the use of a fake cannot ensure compliance with the performance characteristics for construction work, and therefore it is mandatory quality control of cement.
How cement is falsified
To make a fake, a high-quality mixture is diluted:
- mineral powders;
- dolomite dust;
- ash;
- caked old cement.
Express ways of checking. Visual control
Quality control of cement when used at particularly critical facilities, it should be carried out in a laboratory. But for private construction, it is quite enough to carry out an express analysis, which allows you to quickly identify a fake. It is based on the properties of cement that change during storage.
How to check the quality of cement in a few minutes? You need to take a few lumps and try to crush them with your fingers. If, when pressed, the lump is soft and easily disintegrates, then the raw material is quite suitable for preparing high-quality concrete. When the destruction requires significant efforts or hard and sharp particles remain, then the cement is damaged.
After evaluating the appearance, an additional check can be carried out by kneading the cement paste on salt-alkaline mineral water such as Essentuki. Note that the mixture will be very caustic. A discoid (cake) is made from the solution - the solidification time of high-quality cement will be less than 10 minutes, and the figure will also be very hot. Falsified mixtures do not heat up and hardly set for an hour.
Also express analysis of cement can be carried out with special instruments - contractometers. They track the reduction in the volume of the water-cement mixture. There are also devices that measure conductivity and estimate cementitiousness.
Laboratory test methods
Laboratory techniques allow you to accurately establish the compliance of cement with the declared brand and are fully regulated by GOST 310.4-81 or GOST 30744-2001 for old and new standards, respectively. The standards regulate the procedures for determining the fineness of grinding, setting periods, uniformity of volume change and bending / compressive strength.
Cement is one of main types of building materials.
It is important to know the storage and operating conditions on which it directly depends.
About, what is the expiration date has cement of various brands, we will tell in the article.
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Is he there?
Like all building mixtures, cement has a specific shelf life.
Long-term storage leads to a decrease in its activity, which directly affects the quality of its composition.
Moreover, the higher the activity, the faster there is a loss of building material qualities... Observing these rules, you can avoid unreasonable financial costs when purchasing cement and prolong its initial quality:
- cement must be purchased at specialized points of sale;
- it is not recommended to buy material in damaged packaging;
- you should not buy cement in advance and stock it up for future use.
It is important to know if the period indicated on the package has expired, even if not long ago, this material is no longer suitable.
What does it depend on?
Maintaining optimal storage conditions will ensure the suitability of the cement and will extend the period specified by the manufacturer. One of the main characteristics is air resistance, which affects the conservation of the level of properties determined by the cement manufacturer in air.
During storage certain conditions must be met:
It is also necessary to ensure good ventilation at the storage location.
Shelf life according to GOST
Each brand of cement, even if all storage conditions are met, after 3 months loses about 15% of its original qualities.
Cement of the M-500 brand is stored in bags for no more than 6 months, then the "grade" will decrease to the level of M-400, which can also be stored for six months, and in the future will no longer be suitable for use.
Depending on the brand of cement it is permissible to store for a certain period:
- M-600 - 3 months;
- M-500 - 6 months;
- M-400 - 6 months.
The shelf life of the material sold in bags established by GOST is one year, but the quality of the product decreases by 15% every 3 months.
GOST 10178-85 is:
- 45 days - high-speed cement grades;
- 60 days - other types of cement.
Does the expiry date depend on the material in which the cement is packed? Currently, cement is packed in paper bags weighing up to 50 kg, where at the same time it is in plastic packaging.
When fully sealed, this container fully provides protection against moisture penetration.
It is also shipped in bulk. With this type of storage, the material is most susceptible to penetration of moisture and a decrease in active qualities cement.
Bulk cement should be stored in barrels, the top of which is wrapped in foil. Storage space plays an important role.
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How does long-term storage affect quality?
Cement activity during long-term storage it is significantly reduced.
Even a purchased product of a higher quality loses all its original qualities in 2-3 months.
Initially, cement is a free-flowing substance, but over time and if the basic storage rules are not followed, the cement turns into stone. Hence it follows that do not stock up for future use.
How to store it correctly in winter and summer?
For storage of material both in winter and in summer, a dry and ventilated room is required. It is important to observe the temperature regime (you need to maintain the temperature regime).
The cement should be placed on pallets, the distance from the bag to the ground should be not less than 30 centimeters... Each bag is hermetically wrapped with cellophane wrap. In summer, the bags can be stored outdoors for some time, having previously installed a water-repellent material between them.
Storage of cement is unacceptable in places like:
- open canopy;
- basement;
- unheated rooms with a high moisture content.
Perfect place storage - a sealed room with a minimum level of humidity.
You can learn how much and how to properly store cement from the video:
After obtaining a building permit, you will find it on our website.
How to understand that cement is unusable?
A number of simple steps will help to check the suitability of the material for further work.
When the powder is squeezed in the palm of the hand, a lump is formed from the mass, but at the same time it should be crumbly: this is a sign of the quality of the cement.
You can tap the bag of cement lightly: if you feel fossils, then this material is no longer suitable for work.
There is another a way to check the quality of the goods. To do this, you must use:
- Plastic bag.
- The container in which the material is mixed.
- Sodium bicarbonate mineral water.
After mixing the cement, a small cake is made with a thickening in the center. Seizure usually occurs within 10 minutes, and the middle of the resulting mass heats up a little.
This is a sign of high quality products. If this does not happen, then the composition of the cement does not meet the required standards, and such material is not suitable for use.
By observing the above points, you will be able to avoid additional financial costs. It should not be forgotten that even if all requirements for storage conditions are met, after 10 years, the cement will still lose its properties.
In summer, the construction season is in full swing, from the cement producers in the eyes dazzled. Autumn is the peak of sales, the price for 50 kg is reduced to 90-100 rubles. In both the first and second cases, it is rather difficult to make a choice: the temptation to save is too great. How to be? How to check the quality of cement? Read about this in the article.
Are there any validation methods available?
Cement, like other building materials, is produced in accordance with GOST. That is, the product is obliged to meet the standards established by legislation. There are laboratories for quality control in production. Control is carried out according to the following parameters:
- compressive strength;
- hardening speed;
- the beginning of setting;
- water separation;
- the content of sulfur oxide, magnesium, aluminum;
- other.
Without laboratory equipment and specialized education, it is impossible to carry out a 100% quality check. What to do? Hope for luck and the Russian "maybe"? Not everything is so sad. There are ways in which you can check cement even at home.
Cement quality control methods
First of all, do not risk buying material from an unknown manufacturer. It is very likely to buy a fake that has nothing to do with the required material. If you bought cement and you have doubts about its quality, pay attention to the following signs.
- The powder is light or dark gray in color, ideally has a greenish tint.
- When squeezed in a fist, it does not stick together, it flows through the fingers.
- When rubbing between the pads of the fingers - soft (rough fake).
- The packaging contains information about the batch number, release date, expiration date.
This is all you can check visually and tactilely. But to determine the chemical properties of cement, you can use the Essentuki-17 mineral water. During the experiment, be careful: the powder, entering into a reaction with dissolved mineral salts, splashes, stains clothes and causes skin burns.
In a container, like a plate, pour ½ cup of cement, add mineral water until a dough-like consistency appears. Stir with a spoon (not with your hands). Now the most interesting thing: make a pancake of arbitrary diameter and thickness in the center 4-5 cm, along the edges - 1 cm or "no". Watch. Real cement sets instantly. The temperature in the center of the pancake is higher than at the edges. If the color of the pancake is up to greenish - grade D-0.
Place the sample in an airtight bag and let sit for at least an hour. Better - for 2-3 days. A cake made of high-quality cement, aged in such conditions, does not have cracks, does not break (a slight ringing is heard), it may be covered with a white coating (salt). The fake cement will seize in lumps, with the formation of cracks.
If you buy cement in bags, watch what is being loaded into the car. High-quality, fresh material has a loose consistency, so the bag sags. Do not bend - take the money and leave. Do you have doubts? Hit the bag lightly with a hammer: if the cement is caked, the hammer will bounce off.
Today, one can often find fake bulk materials, low-quality cement, sand, etc. At the same time, it is not possible to check the quality of cement due to the fact that it is in bags (no one will allow opening bags of cement).
But high-quality and real cement is a very important element at a construction site. If the cement is poor, of poor quality, then the concrete, plaster, floor screed, etc., will also have less than ideal characteristics. How can you check the quality of the cement? What happens if you use bad cement for construction?
Poor-quality cement will surely make itself felt in a short period of time. In addition, when using poor cement, its consumption increases significantly, which, of course, leads to unforeseen financial waste.
Whether it is a floor screed or a foundation, it does not matter what the strength of concrete can be said if bad cement was taken for its preparation? Of course, then, over time, cracks appear on the walls due to shrinkage of the foundation or the floor screed bursts due to the use of low-quality cement. 
Today, it is increasingly possible to buy low quality cement on the construction markets. Not only is it overdue for a couple of months, but it was not clear what components were taken for its manufacture. Below, in this article of a construction magazine, it will be told about what exactly fake cement is made of.
Counterfeit cement - what replaces the real product?
You have come to the market hoping to buy cement. We found the lowest price, came home, and let's build. Did you know that you may have purchased fake cement, because a good and high-quality product cannot cost little money. 
If we talk about a fake, then instead of cement you can buy:
- Dolomite dust (high percentage) instead of the main components;
- Powder from fire extinguishers, thoroughly mixed with dust from filters of cement plants;
- Expired cement, which is ground back to the desired consistency.
Accordingly, having bought fake cement, you can forget about the quality of the concrete structure once and for all. That is why it is so important to buy cement only from trusted companies and manufacturers who value their reputation more than profit.
Now we will consider several ways how to check the quality of cement without leaving the checkout. First of all, you should understand that no one will give you a chance to open a bag of cement in a store without purchasing it. Second, you should know that the weight of cement is much lower than that of a gypsum mixture, therefore, it is possible to determine in advance, by weight, the quality of the products sold (however, this is not always accurate).
If we talk about a store check of cement, then you can go one more way: check how loose the cement remained in the corners of the bags. If there is even the slightest suspicion of the possible fossilization of cement, then it is best to immediately refuse to buy it, since this is an expired cement of poor quality. 
It is possible to more accurately determine how high-quality cement is, either in the laboratory or at home. To test the cement at home, take a small amount of Essentuki 17 mineral water, after which, try to mix, using mineral water, a small amount of cement in a metal bowl.
If you have high-quality cement in front of you, then it is necessary:
- Will change color, become slightly greenish or bluish;
- It will harden almost immediately (low-quality cement can harden for half an hour or more, in time);
- The metal container for mixing the cement mortar will become noticeably warmer (the cement will begin to generate heat).
In the event that it is possible to touch and touch the cement with your hand, before buying, then pay attention to the following points:
- When squeezed in the hand, high-quality cement will not become a lump, it will surely crumble into dust after the palm is unclenched.
- High quality cement has a uniform color, there is not even the slightest suspicion of lumps in it.
If you still doubt and are not sure of the correctness of your actions, then follow the most proven method of determining the quality of cement, of all of the above. 
First, do not deprive the laboratories of the work, because you can always turn to specialists for help. Secondly, read the real reviews of cement buyers in your city, for sure there are such reviews in every region of Russia, Ukraine, and other countries.
It is no secret that, in terms of sales volume, cement is one of the most popular building materials in Russia. Indeed, the cement market is huge and the demand for it is growing from year to year. Of course, this fact has come to the attention of scammers for quite some time. They are trying by all available means to sell either low-quality cement, or "gray mixture", which, in fact, is not cement.
And if large construction companies or precast concrete factories have their own laboratories that allow you to accurately determine the main properties of cement (activity, brand, speed and uniformity of setting), then small contractors and "ordinary" people can only rely on the seller's "word of honor".
Fortunately, it's not all bad. There are several ways that will help you check the quality of cement in 10-15 minutes and weed out the obviously bad material.
Where is the danger?
So, in practice, you run the risk of buying either stale cement, which has lost the lion's share of its activity (and, therefore, brand strength), or a material that has nothing to do with cement. As a rule, this is a mineral powder for the production of asphalt concrete, dolomite dust (filling of powder fire extinguishers), re-ground cement, fly ash, etc. All these "mixtures" are gray, which confuses buyers. They can even grasp, but strength is out of the question.
How to protect yourself from counterfeiting?
The first and most important piece of advice is to buy cement only from sellers in whom you are confident. The supplier must be in the market for at least 2-3 years. In no case do not take the cement "hand-held".
In addition, for each batch of cement, the seller must provide a full package of accompanying documents, ranging from certificates and quality certificates, and ending with factory invoices for the goods, which indicate the brand of cement, its weight, date of manufacture and shipment.
Of course, this will not help you to protect yourself from counterfeiting by 100%, but it will significantly reduce the risks, which is already good.
How to determine the quality of cement?
First of all, you should "evaluate" the appearance of the cement. It is a dry homogeneous powder of gray color - from light to dark gray, sometimes with shades of green. The fresh powder is quite heavy (much heavier than gypsum) and is fluid like water.
Note that if the cement "lays down" a little, lumps will form in it. If they are soft to the touch and easily disintegrate when squeezed with your fingers, it's okay. But if a significant effort is needed to destroy them and they disintegrate into solid particles with sharp edges, the cement is spoiled and has already lost the lion's share of its activity. We do not recommend using it.
Is the appearance of the cement not suspicious? Then we turn to an express analysis of its quality.
For the "experiment" you will need mineral water (for example, Essentuki No. 17), a disposable plate, a plastic bag and rubber gloves (protection against chemical burns). So, we knead the cement in a plate on our water, and then from the “dough” we quickly make a “cake” with a thick middle and thin edges.
We look at the result:
- good cement sets immediately - in 5-10 minutes, and the "cake" itself heats up noticeably in the thick part;
- mixtures of mineral powders and other incomprehensible ingredients do not set within 30-60 minutes and hardly heat up;
- highly diluted cement sets in fragments, with the formation of subsidence and cracks;
- Chinese cement of not very high quality sets strongly almost immediately, heats up quickly (sometimes to vaporization) and often bursts from thermal deformations;
- dust from electrostatic precipitators and other waste does not react in any way.
If the "cake" has grabbed, we wrap it tightly in a bag together with a wet rag and leave it in a warm place for 1-3 days. We evaluate the result. Good cement is hard, almost free of cracks, rings when tapped and shatters when dropped. The bad one is covered in cracks, it can split into several pieces in the hands or crumble into crumbs.
Another tip - if you are taking cement in bags or big bags, feel the edges. Solid? This means that the cement is "stale" and should not be taken.
The 01Beton company works absolutely honestly and only with trusted cement manufacturers, therefore we provide a full package of accompanying documentation for each batch. We guarantee the quality of our products, so we are not afraid to reveal the secrets of its verification.
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