Which reagents are used as deicers:

1. Technical salt
2. Calcium chloride
3. Sodium formate (potassium formate)
4. Magnesium chloride (Bishofite)

Of the advantages of the above anti-icing compounds, you can list:

• Efficiency
• Reliable
• Speed ​​of Impact
• Economic price
• Human Safety

Commercial salt is a time-tested deicer. It has been used in this purpose since 1960 as an anti-icing sand-salt mixture. After 1995, technical salt was used in its pure form. The advantages of industrial salt are low price, availability, long-term exposure and the ability to withstand low temperatures down to -20˚С. But at the same time, salt has a significant drawback, namely, the ability to corrode metals, rubber and accumulate in the soil, thereby negatively affecting the environment.

Calcium chloride has a much less negative impact than technical salt or its mixture with sand. At the same time, the consumption of calcium chloride is 20-30% less than sodium chloride and withstands temperatures lower, namely up to -35˚С. In addition, it has been scientifically proven that calcium chloride replaces technical salt and has a positive effect on the soil. Among the shortcomings can be listed – a shorter period of validity (about 3 hours), a negative effect on rubber and the ability to change the color of materials (whitening).

Another anti-icing material that has won its place among de-icer is =”color: #ff0000;”> bischofite or magnesium chloride</span >.

Bishofite anti-icing agent benefits:

1. It has a milder effect compared to sodium and calcium chlorides.
2. Twice as effective as sodium chloride
3. Will withstand temperatures down to -35˚C
4. Magnesium chloride is a trace element for crop production, so there is no negative impact on the soil
5. Contains less chlorine than calcium and sodium
6. Does not damage concrete or asphalt surfaces
7. Economical, has low consumption rates.
8. Effective in clearing snow, removing ice and snow crust.

Bishofite consumption at -20˚С is 90gr/m2.

Sodium formate or sodium formate – chlorine-free deicer. Included in the de-icer for aviation. It has established itself as an effective remedy against ice and snow cover, including rolled snow. It has good anti-corrosion properties and is capable of complete biodegradation in 1 month. Sodium formate withstands air temperatures down to -20˚С.
To achieve crystallization at lower temperatures, a combination of sodium formic acid with other salts is allowed. It is noteworthy that formate is able to reduce the corrosive activity and the negative impact on the road surface of other salts

Sodium formate consumption is 25g/m2.

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The history of this pigment dates back to ancient times, more precisely after the Cretaceous period. When the volumes of the oceans decreased and became numb. Then, along with the newly formed land, the remains of ancient marine animals came to the surface in the form of limestone deposits, which had accumulated on the seabed for many millions of years. Limestone, aka chalk or calcium carbonate – this is the first white pigment known to mankind. Later, white clay or kaolinite mineral (kaolin).

The use of mineral dyes in ancient times.

Ancient people used these pigments for rock art, as well as for application to the body in rituals and ceremonies. Small tribes in Africa, New Guinea and South America, who have preserved their ancient traditions, use natural white pigments in their customs to this day. In addition, chalk and kaolin are successfully used as fillers in manufacturing, cosmetics and construction industries.
Masters of Kievan Rus back in the 11th-12th centuries had a number of natural pigments in their arsenal, which helped them create masterpieces of art of that time.< /span>

Synthetic white pigments and their applications.

Later, with the advent of technology and production, chemically synthesized substances appeared in everyday life. One of these synthetic pigments was lead dioxide or lead white, obtained from lead ore. Thanks to its color fastness and excellent hiding power, it became in demand in Europe at that time. Several centuries ago, at the turn of the 17th century, ladies even used it to whiten their skin. However, due to its toxic effects on humans, lead dioxide has ceased to be used. Moreover, it is currently banned from production.
In the 19th century, the safe zinc oxide. And here it is worth noting that zinc white, as a pigment for paints, had several drawbacks. They are more expensive in price, with a lower color saturation and a cold tint, as well as a weak hiding power, for a long time could not completely displace lead dioxide from the market.

This situation continued until the beginning of the 20th century, namely until the advent of titanium dioxide.

Titanium white immediately conquered the world market as:

1. White pigment for paints and plastics
2. White pigment for concrete and epoxy
3. Dyes for the food industry – food grade titanium dioxide
4. White pigment for foundation and other cosmetics
5. Dyes for process fluids, soaps
6. White color pigment for paper and textile industry
7. Coloring agent for rubber
8. Pigment in pharmaceuticals

It should be added that due to the rich snow-white color, warm shade, opacity, high hiding power, inexpensive price, the production of white pigment titanium dioxide occupies a leading position.

Demand creates supply, so it is currently possible to buy white pigment in several brands, depending on the request of the buyer and the industry in which the substance is used. For example, titanium dioxide produced in Ukraine has the following grades: RTs-10, R-202, R-203, R-206, RTs-9, RTs-20 and some others.

You can read more about the white pigment titanium dioxide here

Another popular pigment today is barium sulfate or barium sulfate. It differs from all barium salts in its low solubility and, therefore, the absence of toxic effects on the human body.

Most often, barium sulfate is used as a white dye in two ways:

• medicine, as barite porridge for radiographic studies.
• lithopon filler pigment, namely barium sulphate combined with zinc sulphide.

Successfully serves in the production of stationery, printing inks, filler for plastics, paper, paints and rubber and in other industries.
Please note that Lithopone-based building materials can only be used for interior work. This is due to the high ability to burn out and the lack of proper weather resistance of the pigment. It is absolutely safe for humans.

Follow the link and see all products from this category

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Similar colored concrete is used for the production of paving slabs, mosaics, self-leveling floors, artificial stone, as well as curbs, fences and other decorative items. Modern technologies make it possible to embody any color fantasies of the customer into reality. And with the help of concrete pigments, truly masterpieces of design art are created.
quality finished product?

How to choose a pigment for concrete.

Before choosing a stain for concrete, consider the following parameters:

• Light fastness is the ability of a pigment not to fade when exposed to sunlight.
• Shine – determines the ability of the pigment to cover the original color of the product.
• Dispersion – the finer the dispersion (pigment particles), the better its coloring ability.
• Oil absorption or oil absorption – indicates the ability of pigment particles to retain oil on their surface.
• Coloring ability – helps the pigment to transfer its color to the coloring surface.
• Alkali resistance – the resistance of the dye to alkalis.

The values ​​of these indicators can be found in the quality certificate on the website of the Novokhim Company on the page of each of the pigments for concrete. For example here, novohim.com.ua.
It should be noted that, in all of the above parameters, mineral or oxide pigments showed the highest properties in practice , namely powdered metal oxides. For example, iron oxide pigments , < a href="https://novohim.com.ua/catalog/stroitelnaya-ximiya/pigmenty-neorganicheskie/xrom-3-oksid-zelenyj-pigment/" target="_blank" rel="noopener noreferrer">chromium oxide< /a>, titanium dioxide.

Today, there are three of the most well-known manufacturers of these stains for concrete products. Namely, the Czech Republic, the Precheza trademark, China – the Tong Chem factory, and Germany – the Lanxess Deuschland Gmbh enterprise.

FULL RANGE OF CONCRETE PIGMENTS CAN BE VIEWED HERE.

The benefits of such pigments are:

How to put it into practice and how much to add iron oxide pigments in concrete?

Pigment consumption is calculated as a percentage of the amount of cement that will be used to make the colored concrete mix. On average it is 1% – 3%, depending on the properties of the given pigment. This indicator reaches a maximum of 6%.

For example, if the mass of cement is 100 kg, then the pigment should add a maximum of 6kg. Excess pigment will not give the mixture a richer shade and will not be economically viable. The exact proportion must be derived empirically, based on the desired color and taking into account the manufacturer’s recommendations. Pigments from different manufacturers have different coloring power.

It is also necessary to take into account that the color of the finished product directly depends on the brand and color of the cement used. If gray cement is used, then you need to understand that you will not get a perfectly clean and bright color. The hue will be muted and not very bright. However, when using white cement, the output color will be more juicy and saturated.

Based on this, we conclude that in the manufacture of concrete products in black, brown or dark red colors, in order to save money, it is quite possible to use gray grades of cement. This will most likely have no effect on the final result. If you want to get a pure yellow, blue or green color, we recommend using white cement.

Compliance with the mixing water proportion plays an important role. excess mixing water also affects the resulting color of the product. The water absorption of pigments is also different. Preliminary samples will help you determine the exact proportion. The larger the dispersion and density of the dye, the less will be its water absorption.

There is one more feature, namely that Czech and German pigments of the same brand are always stable in their shade, which is impossible say about pigments made in China. You can buy Chinese iron oxide pigments of the same brand, but from different batches and they may have different shades.

In connection with the above, when making a large order of paving slabs or any other products, preliminary tests for color and water absorption should be done , take into account the cement and filler used. When using Chinese pigments, batches should be made from the same batch of dye.

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How to do construction work in winter?

The latter are regulated by the use of special building antifreeze additives.

Why does concrete harden slowly in winter?

When carrying out construction work using concrete, it should be borne in mind that the process of its hardening, which required only a few hours in summer, is already at a temperature of +5° It takes several days. With a decrease in temperature to 0 ° C, it slows down significantly. If the thermometer drops to -3-6°С, hydration and solidification will practically stop.

This feature of the mortar behavior is explained by the presence of water in it, which solidifies when the temperature drops, thereby disrupting the hydration process. And correspondingly. setting and hardening of concrete. Given this, it is advisable to resort to the use of winter construction methods when the thermometer drops to + 10 ° C, introducing anti-frost additives for concrete into the solution.

What are antifreeze additives for concrete?

The main construction methods in winter include electric heating of concrete, concreting in greenhouses, heating formwork and other similar methods. Unfortunately, it is not always possible to use such technologies. In this case, the optimal solution is the introduction of special antifreeze additives into the composition of concrete mixtures, which significantly accelerate the process of setting and hardening of the mortar at low temperatures.

What are antifreeze additives?

Next, we will look at the most popular antifreeze additives that exist today, dwell on their advantages and disadvantages.

• Calcium chloride

The undisputed leader, the most popular and effective concrete accelerator. Its unique properties were discovered and adopted at the end of the 19th century.

The benefits of calcium chloride.

1. Calcium chloride is non-toxic and non-flammable,
2. Demonstrates plasticizer properties by reducing water separation
3. Calcium chloride increases the resistance of concrete to moisture penetration, while increasing its strength and performance.
4. The introduction of this frost-resistant additive into concrete mixtures makes it possible to obtain an excellent material for pouring floors, laying sidewalks and creating other road surfaces.
5. Another advantage of this admixture is its cost-effectiveness, since a small dose of CaCl2 is required in the concrete mixture.

However, it has a significant drawback – the tendency to corrode the reinforcement in case of moisture, and, as a result, is prohibited for use in prestressed reinforced concrete.

At the same time, calcium chloride in an amount of 2% increases the electrical conductivity of fresh concrete pouring by 4-5 times, which should be taken into account when applying voltage .

If the work is carried out in accordance with the recommendations, with strict observing the concrete preparation technology, with careful isolation of the reinforcement from moisture penetration, calcium chloride will be the best solution as an anti-frost additive.

• Sodium formate or sodium formate

Slightly inferior to the leader, but quite effective as an antifreeze additive. Sodium formate is similar in its properties to sodium nitrite, but has a number of significant advantages over it.

Sodium formic acid is non-toxic, explosion and fire safe, does not cause corrosion of steel structures and embedded elements. The antifreeze additive HCO2Na allows you to perform construction work using concrete mixtures when the temperature drops to -15 ° C.

• Potash – potassium carbonate, K2CO3

Irreplaceable in Siberia, in the construction of residential buildings and agricultural buildings at significantly reduced temperatures.

Among the advantages of this anti-frost admixture in concrete mixtures is a high degree of acceleration of the concrete setting and curing process. As well as the ability to maintain efficiency at temperatures up to -30-32 ° C and the absence of a corrosive effect on reinforcement. Moreover, it is non-toxic and non-flammable. In addition, potash does not cause salt efflorescence on the surface of concrete stone and does not weaken the setting of concrete with stressed reinforcement.

Disadvantages of potassium carbonate include:

1. Tends to form a caustic alkaline compound during curing. Therefore, it is not recommended to use it in a solution with active silica.
2. Also, do not use this antifreeze additive for working at temperatures close to 0°C and above. This is due to the fact that the concrete mixture thickens and sets very quickly under its influence.
3. Potassium carbonate is very hygroscopic, it “spreads” in air, which is why it should not be used in high humidity conditions.
4. It should be remembered that potash is added to concrete mixtures containing lime and used near high voltage sources.< /li>

As for the introduction of potassium carbonate into the solution, it can be added both in dry and dissolved form. And the amount of anti-frost additive introduced depends on the ambient temperature and the mass of cement used. Since potassium carbonate causes an alkaline reaction, all work should be carried out using personal protective equipment: goggles, gloves, respirators and overalls.

Urea, aka urea CO(NH2)2

Not used as a stand-alone substance for concrete mixtures, but included in complex antifreeze additives, for example with nitrite , nitrate and calcium chloride, nitrite and calcium nitrate, with calcium nitrate and in other combinations. Acts as a plasticizer and salt removal regulator. In addition, carbamide is able to lower the temperature of the liquid in the pores of concrete and regulate the rate of hardening of the concrete mixture.

Sodium Sulphate or sodium sulfate Na2SO4

Can be used as an independent anti-frost additive, or as part of plasticizers for concrete mixes, significantly enhancing their effectiveness.

Sodium sulfate increases the strength of concrete by 3-4 times and accelerates its hardening at low temperatures up to 24 hours, depending on the mineral composition of cements . At the same time, sodium sulfate is poorly soluble in water. In some types of cements, it can cause corrosion if its amount exceeds 1% in the total composition of the mixture. And at a concentration of more than 2% by weight of cement causes strong efflorescence on the surface of the concrete stone. In addition, in the case of long-term storage, sodium sulfate is prone to weathering.

Calcium nitrate, otherwisecalcium nitrate, calcium nitrate Ca(NO3) 2

Similarly to the previous one, calcium nitrate, an anti-frost additive in concrete solutions, can be used both independently and in combination with other substances. For example, such as urea, nitrite, nitrate and calcium chloride.

The advantages of calcium nitrate as an antifreeze additive in concrete mixtures include the possibility of its use when performing work using reinforcement, increasing the moisture resistance of concrete structures, increase of frost resistance of concrete up to -20°C. As well as a significant reduction in the setting and hardening time of the concrete mix – up to 14-20 hours.

Among the disadvantages of calcium nitrate, one should indicate its fire hazard, high hygroscopicity, up to a tendency to blur in air and the high price of calcium nitrate as an independent additive .

Ammonia water or ammonia water NH4OH

The most budget-friendly of all products in this class. This antifreeze additive for concrete mixtures does not cause corrosion of metals and forms efflorescence on the surface of the concrete coating, it is approved for use in stressed reinforced concrete structures.

At the same time, ammonia water has a number of significant drawbacks. First of all, it is a pungent smell, which implies the presence of powerful ventilation and the need to monitor the concentration of ammonia in the air. For the same reason, it is prohibited for use in the construction of residential buildings and livestock complexes. Another disadvantage of aqueous ammonia is the inadmissibility of early operational loads. In addition, ammonia water, when introduced into the composition of concrete, evaporates very quickly. Accordingly, the surface poured with concrete must be covered with a film and kept to a technologically necessary minimum in order to avoid delamination of the upper layers of the coating.

Sodium chloride, otherwise called technical salt, NaCl

Another inexpensive antifreeze concrete admixture that is readily available and non-toxic. However, it should be remembered that technical salt causes severe corrosion of reinforcement, efflorescence and efflorescence on the surface. It also forms wet spots on plaster.

When choosing the optimal antifreeze additive for concrete mortar, remember that its action directly depends on the components of the building mixture with which it enters into a chemical reaction. And also from the brand of cement, its manufacturer, concrete mix modifier components and the type of cement used.filler: gravel, sand, limestone and other materials.

It should be noted that some imported anti-frost additives, which have proven themselves well in construction work abroad, no longer work when interacting with domestic materials so effective. To get a really good result, it is necessary that all the components of the concrete mixture are produced by the same manufacturer as the antifreeze additive. And this option is unacceptable for budget construction.

Using anti-frost additives for concrete mortars during construction, the recommended dosages should be strictly observed, since their excess can adversely affect the quality of the concrete structure: worsen the physical and chemical properties of concrete, shrink, and so on.

Dosage of antifreeze additives.

For convenience, here is a table of average dosages of antifreeze additives that can be used as a guide when preparing a solution.

A method of introducing antifreeze additives into concrete.

To obtain a high-quality concrete mortar, you must first dissolve the anti-frost additive in water. Then the resulting solution is introduced into the concrete, bringing it to the required percentage of the mass of cement. This percentage directly depends on the air temperature and the type of additive used.

It should be remembered that no additive is a panacea for winter building work. This is just one of the methods of an integrated approach to accomplishing such a task, and in some cases, heating the concrete with the use of an anti-frost additive is mandatory.

We must not forget that all additives are different, have different properties and behave differently from each other even in the same weather conditions. Therefore, before making a decision in favor of one of them, you should carefully study its characteristics and recommendations for use. In addition, conduct experimental studies in the conditions of the upcoming construction project.

Safety precautions.

We must not forget that working with anti-frost additives for concrete requires strict adherence to safety measures. Because some of them are toxic or flammable, such as urea and sodium nitrite.

The warehouse for storing these additives must be equipped with fire fighting equipment and have access to a fire hydrant. Workers should be instructed on which chemicals they will work with. We recommend equipping places for storing personal belongings and eating in a room isolated from these substances.

When working with antifreeze additives, it is necessary to use overalls and personal protective equipment: goggles, gloves, respirators and special clothing.

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