Chemical additives in concrete. Additives in concrete of the Polyplast company

Concrete is the most well-known and commonly used building mix, consisting of cement, aggregate and water. But since it is used not only for the installation of walls and ceilings of residential and public buildings, but also for hydraulic structures, foundations, special-purpose structures (supports of bridges, viaducts, etc.), then in each individual case a substance that has the general name "concrete" cannot be the same.

Each time when designing objects, the calculation of structures is carried out, taking into account all the conditions not only for their construction, but also for their further operation. And since the operating conditions are different, the concrete solution must also be different.

Therefore, to give concrete the desired properties, various additives are used that change not only the properties of the liquid concrete mixture, but also the hardened concrete itself.

Additives for concrete - classification

There are a lot of additives, and therefore they are classified in different ways. The following is one of the most commonly used classifications:

Concrete modifiers - are able to increase the strength of the concrete mixture and its frost resistance, reduce its permeability, extend the service life of the finished concrete mixture. At the same time, they do not reduce the mobility of the mixture, which increases the efficiency of its use and facilitates the work.
Mobility regulators - they are used in hot weather or in cases of long-term transport of concrete in order to maintain the necessary plasticity.
plasticizing additives. Their use allows to reduce the consumption of concrete without reducing its strength. They also make it possible to improve the mobility of the solution, increase its density, and in some cases its water resistance.
Antifreeze additives - are used when laying concrete in winter at temperatures up to -15 and even up to -25 degrees.
Additives for self-compacting concrete - used when it is necessary to pour thin-walled concrete structures.
Additives to accelerate the curing of strength - improve this indicator in the first day after laying the mixture, and also increase the strength of already hardened concrete.

There are situations when it is necessary to improve several indicators of the concrete mix at once. Then complex additives are used that can affect several indicators at once.

The use of several additives in such a situation can lead to unpredictable results, and a properly dosed complex preparation guarantees the required quality of concrete.

All substances added to the concrete mixture can also be divided into 2 large groups:

(powders, emulsions and aqueous solutions) - are introduced into concrete in small quantities.
Finely ground substances (mineral substances of fine grinding) - are used if it is necessary to save cement and obtain resistant dense concrete.

Chemical additives subdivided according to the effect that they have on the concrete mixture:

hydrophobic;
increasing the plasticity and mobility of the mixture;
antifreeze;
reducing the separation of liquid from the solution;
stabilizers that prevent liquid concrete from stratifying;
curing accelerators;
regulators of deformation processes;
setting retarders;
gas and foaming additives that increase the porosity of concrete;
increasing resistance to aggressive environments, corrosion.

concrete modifiers

These substances are intended for the manufacture of special-purpose concretes with high technological properties: low water permeability (grade not lower than W12), high strength (up to B125), corrosion resistance and durability.

Some modifiers are designed to produce expanding, stressing and compensating for shrinkage of concretes and mortars.

These additives are mainly used for the manufacture of conventional and prestressed products by vibrocompression and molding.

Concrete flow regulators

They are used in situations where it is impossible to organize the production of a concrete mix of the required quality directly next to the construction site and you have to transport concrete from afar. These substances are also necessary when the production technology provides for a long process of laying the mixture.

Usually these substances are part of complex additives.

They are made from:

inorganic substances;
organic materials;
organomineral combinations.

Natural additives are produced mainly from waste products of the agrochemical, petrochemical and timber industries.

Additives of inorganic origin are made on the basis of formaldehyde and naphthalenesulfonic acid concentrates.

They give the mixture the following qualities:

high fluidity;
increased strength;
resistance to temperature changes.

These substances reduce the cost of concrete work, reduce the consumption of cement in the manufacture of concrete, have a positive effect on the adhesive properties of reinforcement (improve the adhesion of reinforcement to concrete).

In such works as pouring columns or heavily reinforced structures, the use of these substances is mandatory.

Antifreeze additives

In the cold season, the process of concrete hardening slows down significantly, which has an extremely negative effect on its strength indicators - concrete becomes loose, and its frost resistance index decreases.

If it is not possible to use concrete heating at the construction site, then they are used, which reduce the freezing point of water and, thus, normalize the concrete hardening process.

Antifreeze additives are a liquid with a density of approximately 1.4 l/kg with a mass fraction of calcium nitrate from 42 to 45% and an activity of hydrogen ions from 5 to 8 pH. The color of the additive depends on the manufacturer and can be light gray, yellowish and even dark brown.

These additives have the following effects on concrete:

accelerate the set of strength;
increase the water resistance of concrete;
increase its mobility;
the corrosion inhibitor contained in the additive protects against oxidation.

The use of antifreeze additives prevents the appearance of efflorescence on the surface of the concrete structure, increases its strength, allows the use of cement of lower grades for the mixture, which reduces the cost of concrete products.

These substances are introduced into the concrete mixture when pouring monolithic and prestressed products - bridges, dams, dams, oil and gas platforms.

The main requirement for these concretes is their resistance to water separation and delamination.

Such concretes are used in densely reinforced structures, when the usual compaction of the mixture is impossible, therefore, concrete is needed, which can only be compacted by its own weight.

Hyperplasticizers are added to these concretes, which make it possible to obtain concretes with ultra-high performance properties.

They are used for the device of monolithic seamless high-strength, shotcrete, reinforcement and restoration of structures.

Additives to accelerate curing

Most often, aqueous solutions of calcium chloride, sodium chloride and other chloride salts are used here. They accelerate the hardening of concrete and are used in the construction of the following structures:

prefabricated reinforced concrete structures;
densely reinforced and thin-walled structures;
products of non-standard forms;
pools.

All these substances are mainly used in the industrial production of concrete and concrete products. In private housing construction, the most used are antifreeze additives and concrete mix hardening accelerators.

What to Consider When Using Concrete Admixtures

When buying an additive, pay attention to the manufacturer. Many imported additives are designed only for concrete made from high quality components that are rarely used. It is better to purchase a domestic supplement from a reliable manufacturer.

When mixing concrete with additives on your own, you need to strictly observe the proportions, otherwise you can get poor quality concrete.

Also learn exactly how to add the supplement - some are administered with water, while others require pre-mixing with one of the dry components of the mixture.

The use of concrete in construction ensures reliable and durable operation of the structure, but for such operating conditions of the facility, it is required to obtain concrete with the necessary characteristics.

Obtaining concrete of a given strength class, water resistance, frost resistance and other characteristics is possible only with the introduction of special chemical additives into the mixture.

Why do we need additives for concrete and mortar

Additives are added to concrete and mortar to improve its performance. The most common are chemical additives to increase the strength of highly loaded structures and hydrophobic compounds to improve frost resistance and water resistance. The use of such additives makes it possible to obtain mixtures with the required mobility to improve the workability and quality of work performed.

Their use is especially relevant in the following cases:

construction of monolithic buildings;
creation of fine-grained concrete or mixture with filler from non-standard fractions;
application in the construction of structures building material with improved properties (stability to water or frost), etc.
high-strength and self-compacting concrete;
floors with increased bearing capacity;
high grade concrete, densely reinforced and especially responsible designs;
road, hydrotechnical concrete, small-piece products;
repair solutions;
concretes on porous aggregates;
paving slabs, cinder blocks;
thin-walled structures (including fencing slabs of "euro-fences").

Classification

The most popular are complex additives that give the concrete mixture several characteristics at once. But there are also substances responsible for one or two or three properties.

In accordance with GOST 24211-2008 Additives for concrete and mortar. General specifications

1 Additives used to modify the properties of mixtures, concretes and mortars, depending on the main effect of the action, are divided into classes given in 4.1.1-4.1.4.

1.1 Additives that regulate the properties of concrete and mortar mixtures:

plasticizing:

superplasticizing,
plasticizing;
water reducing:

super water reducing,
water reducing;

stabilizing;
regulating the persistence of mobility;
increasing air (gas) content.

1.2 Additives that regulate the properties of concretes and mortars:

regulating the kinetics of hardening:

accelerators,
moderators;

increasing strength;
reducing permeability;
increasing protective properties in relation to steel reinforcement;
increasing frost resistance;
increasing corrosion resistance;
expanding.

1.3 Additives that give concrete and mortar special properties:

antifreeze:

for "cold" concrete,
for "warm" concrete;

hydrophobic;
photocatalytic.

(Changed edition, Rev. N 1).

1.4 Mineral supplements

1.4.1 Mineral additives, depending on the nature of interaction with cement hydration products, are divided into types;

type I - active mineral;
type II - inert mineral.

1.4.2 Active mineral additives are divided into the following groups:

having astringent properties;
having pozzolanic activity;
possessing both astringent properties and pozzolanic activity.

2 The symbol of the additive must contain the name of the additive and the class to which it belongs.

The standard classification distinguishes six main groups of additives for concrete:

superplasticizers. Increase the mobility of the concrete mixture, increase its strength, reduce the consumption of cement;
hardening accelerators. Reduce the curing time of concrete;
mobility regulators. Helps to keep the concrete mix in a liquid state for transportation or use in hot weather;
additives with antifreeze effect. They allow to work with concrete at sub-zero temperatures (from -15°C to -25°C, depending on the characteristics of the mixed material);
modifiers. Universal substances that allow you to change several characteristics at once, including increasing the strength class to B80, when using cement grade 500;
improve self-sealing. Allows you to effectively concrete thin-walled structures or buildings where a lot of reinforcing elements are used.

Additives for concrete and mortars: features, characteristics and application of each type

Each type of additive has its own characteristics and capabilities, moreover, they differ. It all depends on what substances the manufacturer used to achieve this or that effect.

Below is a brief description of each group of concrete admixtures. Data such as "density", "appearance", "pH value" may vary from additive to additive. We used as a guide the characteristics of goods from (of the first product mentioned in the cell "In the catalog"). If you buy additives from another manufacturer, check their characteristics in advance.

Increasing the mobility and spreadability of the concrete mixture is the main task of the plasticizing additive. An additional, but insignificant plus is the increase in the threshold of frost resistance. The plasticizer works due to the fact that it allows you to create a concrete composition with an optimal concentration of water.

Mixtures using additives of this class are used for:

creating concrete screeds;
organization of warm and self-leveling floors;
floor slab castings;
pouring industrial floors.

Kinds

Plasticizing additives are divided into three large groups:

Group II - highly plasticizing. It includes:

Aplassan APL. Dark liquid with a weak alkaline reaction. It also has a stabilizing effect. Increases the workability of the mixture;
Lignopan B-3. Consists of inorganic salts of polymer esters of the acrylic series and cellulose. Stabilizes and reduces the separation of water in the concrete mixture;

Group III - medium plasticizing. They increase the mobility of the mixture from P1 to P3 without compromising the characteristics of concrete. This class includes:

LST (technical lignosulfate). Appears as a dark brown viscous liquid;
MPC (Melting of dicarboxylic acids). It is a mixture of glutaric, succinic and adipic acids. Color dark gray or dark green;
C-1. Polycondensation product of formaldehyde, salicylic acid and mono-ethanolamine. It is dark brown in color and has a distinct smell. Reduces the rate of chemical reactions and reduces the rate of air entrainment;

Group IV - slightly plasticizing. Able to change the mobility of the mixture from P1 to P2. This group includes:

NChK. It contains calcium and sodium salts of sulfonic acids as a base. Has a dark brown color;
KCHNR. It is an aqueous solution of neutralized tar. Also dark brown;
CHSS. It is an aqueous solution with various organic and inorganic substances. Waste from pulp production.

Group I can stand apart - superplasticizers, which will be discussed in the next section.

Summary table of properties

In the Cemmix catalog
Appearance
Density	1.19 kg/dm3 (at 20°С)
pH value	7,2 - 8,5
The basis	Polyfunctional modifier
Dosage per 100 kg	up to 1 liter
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014
Compatibility	Can be combined with other Cemmix materials, but optimizing the composition and properties of the concrete mixture requires laboratory testing.
Disposal

Application

As already mentioned, the basic task of a plasticizer is to increase the fluidity of the mixture. The screed becomes self-leveling and spreads easily over the floor surface. Other advantages of the mixture with plasticizing additives:

saving cement;
reduced labor costs to obtain a smooth surface;
reducing the risk of cracking;
increased resistance to abrasion;
improved connection with the reinforcing cage;
shrinkage reduction;
increasing resistance to temperature fluctuations.

Thanks to the addition of CemThermo, the worker is able to create a screed with a thickness of 3 mm or more without fear of delamination or cracking. Also, the mixture reduces water demand by 10-20%, and heat transfer increases by 10-15%.

How to use

Before use, it is necessary to prepare a concrete solution with the addition of:

Pour the additive into 50% of the recommended water (may be from 10 to 15% of the mixture, the final value depends on the quality of cement, sand, other filler);
Enter the mixture into the concrete mixer, where the concrete is already mixed;
Stir until smooth;
Add water until the mixture reaches the desired level of plasticity.

The consumption of the additive is determined depending on the requirements for the concrete mixture. The recommended composition of the solution is in the table below.

Component	Device of couplers M150		Self-leveling floors M200
1 cube	85 liters	1 cube	85 liters
Cement, kg
Sand, kg	1400		1350
Water, l
Additive, l		0,35

Video: complex additive for filling the floor and screed

Superplasticizers are universal multi-component additives that make it possible to produce concrete mixtures with intensive strength development and high mobility. They are distinguished from plasticizers by an increased fluidity index, which lasts for a longer period. Main areas of use:

production of ready-mixed concrete and reinforced concrete products;
creation of repair solutions;
foundation concreting;
production of paving slabs, cinder blocks, eurofences;
the device of floors, couplers.

Kinds

Superplasticizing additives are as follows:

C-3. It consists of condensation products of formaldehyde and naphthalenesulfonic acid (sodium salts). Can be supplied in both powder and liquid form;
10-03. It is an oligomeric product of the polycondensation of sulfonated trimethylmelamine. Appears as a clear yellowish liquid with a slight opalescent effect;
DF. It is made on the basis of condensation of sulfonic acids of naphthalene (or substances close to it) with formaldehyde;
MF-AR. Obtained by polycondensation of melamine, formaldehyde and sodium sulfonate. Appears as a yellowish liquid;
40-03. It is a mixture of sodium salts of polycondensation products with formaldehyde of sulfonated aromatic hydrocarbons, which are released during catalytic cracking and pyrolysis of petroleum products;
SMF. It is a mixture of compounds that are obtained by the condensation of sulfonic acids of naphthalene and phenol sulfonic acid with formaldehyde, neutralized with sodium hydroxide.

Summary table of properties

In the Cemmix catalog
Appearance	Light brown cloudy liquid
Density	1.19 kg/dm3 (at 20°С)
pH value	7,2 - 8,5
The basis
Dosage per 100 kg	1 liter
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014
Compatibility	Pairs well with other products
Disposal	It is impossible to pour the composition into water, soil, sewerage, it must be disposed of according to the rules of your locality.

Application

Obtaining super-flexible concrete mixtures is the main purpose of using superplasticizing additives. At the same time, it is possible to achieve improved strength indicators of concrete structures, reduce the load on the teams that perform concrete laying, since the work becomes much easier. Other benefits of using:

significant reduction in cement consumption;
ensuring the possibility of laying the mixture without vibration;
extension of the concrete mix life cycle up to two hours;
reduced risk of delamination and early hardening;
prevention of cracks.

How to use

The preparation of the solution is reminiscent of working with plasticizing additives. You need:

Measure 50% of the volume of recommended water (range from 10 to 15% of the total volume of the mixture);
Transfer the mixture to a container with ready-made concrete and mix thoroughly;
The rest of the water is poured in portions until the required plasticity of the mixture is achieved.

Consumption may vary depending on concrete mix requirements. The recommended composition of the solution is presented in the table below.

Concrete brand	Volume of concrete	Cement kg	Sand kg	Crushed stone kg	Water kg	Additive l.

M150P3	1 cube			1250
85l						0,25
M200P3	1 cube			1250
85l					0,25
M250P3	1 cube			1240
85l
M300P3	1 cube			1240
85l

Water-reducing additives allow you to create a concrete mixture with a reduced water content. They help to provide the composition with an increased density, which has a beneficial effect on the durability and frost resistance of finished products. Additives of this kind are used in the following products:

foundations;
monolithic walls;
road surface for highways and federal highways;
blind area for curly elements, etc.

Kinds

As water-reducing additives can be:

Aplassant;
Acetone-formal-dehyde resin (ACF-ZM);
Water-soluble preparation (VRP, VRP-E50);
Water-soluble preparation VRP-350, S-1;
GKZH-10 (sodium ethyl siliconate), GKZH-11 (sodium methyl siliconate);
Wood chemical additive (LHD);
Technical lignosulfonate (LST, LTM, LSTM-2);
"Monolith-1";
Neutralized black contact (NCC) (regular and refined);
The melt of dicarboxylic acids (MPC);
Soap lye (PMShch);
Polyconjugated polymeric phenol (PPP);
Phenolic wood chemical viscosity reducer (PFLH);
Saponified water-soluble resin (VLHK);
Sulphated black liquor (ChSh);
Alkaline effluent from caprolactam production (SCHSPK, SCHSPK).

All water-reducing additives are divided into several groups. The first includes materials that reduce water consumption by 20%. They are also called super water reducing. In the second group, additives that reduce consumption by 12-19%, in the third - by 6-11%, in the fourth - by 5% and below.

Summary table of properties

In the Cemmix catalog
Appearance	Cloudy light brown liquid
Density	1.19 kg/dm3 (at 20°С)
pH value	7,2 - 8,5
The basis	Modified sodiume
Dosage per 100 kg	0.5 - 1 liter
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014
Chem. details
Compatibility	Can be combined with other Cemmix materials.
Disposal	According to local regulations. It is forbidden to pour into water, soil, sewerage.

Application

The use of water-reducing additives reduces the volume of intergranular space, due to which closer contact is provided between the components of the concrete mixture. This contributes to the creation of a strong and dense structure, which leads to a decrease in porosity. Other benefits of using water reduction additives:

reduction of cement consumption;
increasing the workability of the mixture;
facilitating mixing;
increased water resistance;
reducing the risk of shrinkage cracks.

How to use

The admixture is added to almost finished concrete as follows:

The required amount of water is measured (10-15% of the volume of the entire mixture);
In half of the liquid, the entire volume of the additive is stirred, after which the suspension is poured into the concrete;
Thorough mixing indicates how much water must be added to the finished solution in order to obtain the desired consistency.

Do not forget to make control mixes taking into account the current environmental conditions and the quality of other materials (cement, filler). All this affects the consumption of the mixture and additives.

Video: complex superplasticizing and water-reducing additive

The hardening accelerator is a complex additive. Main action accelerator - an increase in the rate of set of stripping and brand strength, an increase in the mobility, durability of concrete structures and mortars; increases the solubility of cement clinker, the degree of interaction with water.

It allows you to increase the early (by 20-40%) and branded (by 15-20%) strength of concrete (with the same workability), adjust the hardening time of the mixture in a fairly wide range. There are additives that ensure the achievement of branded strength of concrete in 7-10 days instead of the standard 28.

Impurities of this class are used in the following cases:

production of reinforced concrete products;
concreting of walls, ceilings;
arrangement of floors, screeds;
production of cinder blocks, eurofences, paving slabs;
creation of ready-mixed concrete at low temperatures;
production of small-piece products;
creation of repair and masonry mortars;
production of concrete on porous fillers.

Kinds

The following substances can be used as strength accelerators:

HC. White crystalline powder. Formula CaCl2 or CaCl2×2H2O;
NK. The formula is Ca(NO3)2 or Ca(NO3)24H2O. Appears as crystals without color;
NOC. A mixture of nitrite and calcium nitrate in the form of a paste or aqueous solution;
HHK. A mixture of calcium nitrite-nitrate with calcium chloride in a ratio of 1:1. Available as a yellowish aqueous solution;
CH. It is Na2SO4×10H2O decahydrate or a salt with the same composition, but without water. The crystals are white-yellow;
HH is a colorless crystalline element. Formula NaNO3;
TNF. Sold as crystalline or fused Na3PO4.

Summary table of properties

In the Cemmix catalog
Appearance
Density	1.185 kg/dm3 (at 20°С)
pH value	7,2-8,5
The basis	Polymethylene naphthalene sulfonates (C-3), inorganic Na salts
Dosage per 100 kg	0.7 - 1.2 liters
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014
Change in composition, formula or chem. details	Adapted to Russian-made concrete aggregates, including slag-alkali components with a high slag content
Compatibility	Works well with other Cemmix materials, but formulation optimization requires lab testing.
Disposal	According to local regulations. Do not pour into water, sewerage, etc.

Application

The main purpose of using the accelerator is to increase the speed of obtaining the branded strength of concrete in order to reduce the construction and repair time. Other benefits:

increasing the water resistance of the composition;
protection against corrosion processes of internal fittings;
increased frost resistance;
reduction of time spent on vibration and heat treatment of the concrete mixture.

If CemFix mixture is used as a hardening accelerator, it is also possible to achieve a reduction in water demand by 10-12%, a reduction in cement consumption by 5-10%. An increase in the grade strength of concrete with this additive occurs by 15-20%.

How to use

The inclusion of additives in the composition of the concrete mixture occurs in the classical way. First you need to measure the required volume of water (10-15% of the total amount of material). We divide the liquid in half and pour all the necessary CemFix into one part, then mix and pour into the concrete solution. Then it remains only to add water until the desired level of plasticity is reached.

Concrete brand	Volume of concrete	Cement kg	Sand kg	Crushed stone kg	Water kg	Additive l
M150P3	1 cube			1250
85l
M200P3	1 cube			1250
85l					0,25
M250P3	1 cube			1240
85l
M300P3	1 cube			1240
85l

Video: CemFix concrete hardening accelerator

Concreting at low temperatures is always difficult. Cement stone hardens very slowly, internal stresses arise in concrete due to frozen water, adhesion with reinforcement, aggregate deteriorates, and the overall strength of the structure decreases. The use of a special antifreeze additive helps to reduce the influence of external factors. It is used if at negative temperatures (not more than -20 ° C) the following work is carried out:

erection of monolithic and precast-monolithic structures;
repair work and the use of masonry mortars;
creation of concretes on porous fillers, etc.

Kinds

There are three main types of antifreeze additives:

antifreezes. They reduce the crystallization temperature of water, reducing the setting time of the solution;
sulfates. They actively emit heat, so that the components in the mixture are distributed evenly. They also accelerate the curing of concrete;
various substances that can form basic and double salts in the composition of the solution. This reduces the freezing temperature of the mixture.

Most antifreeze additives act in a complex way, so they may include several of the components listed above.

Summary table of properties

In the Cemmix catalog
Appearance	Light brown cloudy liquid
Density	1.185 kg/dm3 (at 20°С)
pH value	7,2 - 8,5
The basis	Polymethylene naphthalene sulfonates, inorganic Na salts
Dosage per 100 kg	up to -10°С - 2 liters up to -20°C - 3.5 liters
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014.
Compatibility	With all Cemmix materials.
Disposal	According to local rules. Do not pour into water, sewer, soil.

Application

The main purpose of such additives is to allow builders to work at low temperatures. But most complex products complement the concrete mixture with other advantages, for example:

guarantee of curing without additional heat treatment;
reduction of water demand of the mixture;
increased adhesion to concrete;
reducing the tendency to cracking;
increased frost resistance;
increase the service life of the finished structure.

How to use

The additive is added to 50% of the recommended water and poured into the concrete/mortar mixture, thoroughly mixed. The rest of the water is poured in portions until the required plasticity of the mixture is achieved. The recommended water consumption may vary from 10 to 15% depending on the quality of the materials used.

In the production of concrete mix, it is recommended to use preheated aggregates. The maximum mixing water temperature should not exceed 70°C. The maximum temperature of the finished concrete mix should not exceed 35°C. The temperature of the concrete mixture during laying, as well as the substrate on which the mixture is to be laid, must be above 5°C. It is necessary to use standard technological measures for winter concreting to protect the concrete of the structure from heat losses in the early stages of hardening.

To prepare the mixture, use water GOST R 51232-98 "Drinking water"

Video: antifreeze complex additive CemFrio

A waterproofing admixture for concrete imparts water-repellent and impervious properties to the final product, thereby extending the service life of the entire structure. Additives of this kind make concrete more durable, reduce porosity, protect reinforcement and iron elements in contact with the structure from corrosion. Hydrophobic additives are actively used in the following cases:

concreting of foundations and underground parts of buildings and structures using collapsible and fixed formwork;
plaster and masonry mortars for facades;
installation of monolithic walls and concrete floors in bathrooms, saunas, basement damp and other premises (especially in case of a threat of groundwater);
all types of concrete works where high demands are placed on the watertightness of the structure.

Kinds

The following types of waterproofing additives are distinguished depending on the composition:

polymeric;
plasticizing;
clogging.

Classification can also be carried out according to the method of action:

penetrating. Contain active substances that increase the resistance of concrete to water, acids, salts;
modifiers. Increase the plasticity and adhesion of the substance;
fiber additives. They contain polymer or other fibers, due to which concrete acquires volumetric reinforcement, and its resistance to moisture, mechanical stress and temperature changes increases.

Summary table of properties

In the Cemmix catalog
Appearance	Clear liquid, no color
Density	1.04 kg/dm3 (at 20°С)
pH value	9,0 - 10,0
The basis	organosilicon
Dosage per 100 kg	1 liter
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014
Compatibility	Can be combined with other Cemmix products, the ratio of components is selected empirically.
Disposal	Do not pour onto soil, drains or water. Dispose of as construction waste according to local regulations.

Application

Water-repellent additive primarily gives concrete strength and resistance to atmospheric precipitation, groundwater. The peculiarity of such an element in the composition is that the finished product retains the property of breathability. Additional positive effects:

frost resistance increases;
reduces the likelihood of efflorescence and mold;
heat loss is reduced;
increased corrosion resistance;
reduced consumption of cement.

How to use

The method of adding a waterproofing additive to the concrete mixture is the same as for other products. The product is introduced into 50% of the recommended water, added to the concrete, and then the rest of the water is added, which is necessary to create a plastic mixture.

Video: how to make waterproof concrete yourself?

Multifunctional additives are needed if it is not possible to create combined mixtures on your own. Such products can have a variety of characteristics, since it all depends on what the manufacturer has set for himself. CemBase, already known to us, can serve as an example of a multifunctional additive. It is simultaneously a superplasticizer, a water-reducing composition, and an antifreeze additive. Let us recall its characteristics:

In the Cemmix catalog
Appearance	Cloudy light brown liquid
Density	1.19 kg/dm3 (at 20°С)
pH value	7,2 - 8,5
The basis	Modified sodiume
Dosage per 100 kg	0.5 - 1 liter
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014
Chem. details	Adapted for use with domestic cements and aggregates

In fact, most additives now are complex, because they provide not only the basic effect, but also give the concrete additional properties. The only exceptions would be mixtures that are made to specifications with the addition of one chemical with a specific effect. But now few people use individual components, because complex additives are much more convenient.

Video about complex additive CH4 (CH 4)

Elasticizer for concrete is a PVA adhesive for construction purposes that helps to strengthen plaster and concrete mortar. Applicable in the following situations:

a more plastic solution is needed;
it is necessary to reduce the hardness of the finished structure;
it is required to increase the adhesion of concrete to the surface.

Such a sealant is suitable not only for concrete mixtures, but also for plaster mortars on gypsum. Possesses moisture-proof properties.

Summary table of properties

In the Cemmix catalog
Appearance	White medium viscosity liquid
Density	1.1 kg/dm3 (at 20°C)
pH value	4,7 - 6,0
The basis	Polyvinyl acetate dispersion, homopolymer, coarsely dispersed, plasticized
Dosage per 100 kg	4 liters
Packing	3 liters, 10 liters
Compatibility	Not determined
Disposal	Dispose of by recycling. Do not pour into sewers, onto the ground, into water.

How to use

PVA is added to concrete in an amount of 5-10% of the total volume. This is about 0.5 liters of glue for 2-3 buckets of cement. Do not add too much water to the solution - 5% is enough. Work with concrete to which glue is added must be carried out at an external temperature of at least 7 ° C.

Video: old-fashioned way: how to simply and affordably improve the quality of cement mortar

Impregnation agents are chemicals that allow you to protect concrete already in finished form. When the foundation or wall hardens, they are impregnated, which forms a film on top that protects against water, minor damage, and destruction due to wind. Impregnation is used in the following cases:

it is necessary to improve the waterproofing properties;
it is required to improve fire resistance indicators;
an acid-resistant surface is required, etc.

Kinds

The most popular impregnations based on the following materials:

acrylic. Sealant that forms a protective layer against UV rays. Helps to resist the effects of chlorine-containing substances. Removes dust from the floor at low loads on it;
polyurethane. Universal, more resistant impregnation. Protects against moisture, chemicals, positively affects the strength of the screed;
epoxy. In fact, it is an independent coating, additional protection for concrete;
colored compositions of various types. Used mainly for design purposes. Unlike paint, they last longer on concrete.

Summary table of properties

In the Cemmix catalog
Appearance	liquid, transparent
Density	1.4 kg/dm3 (at 20°C)
pH value	10-13
The basis	Soda water glass
Packing	5 liters
Technical documentation	TU 2499-007-90557835-2014, GOST 13078-81
Compound	silicon dioxide - 27 ... .33.1%; oxides of iron and aluminum - less than 0.25 .... 0.4%; sulfuric anhydride -0.12….1%; sodium oxide - 9.8 .... 13.2%; calcium oxide - 0.20 ... 0.25%.
Compatibility	Can be combined with other Cemmix formulations
Disposal	Disposal is carried out according to local regulations.

Application

Chemical impregnation additive for concrete Cemmix Liqui can appear in three guises:

Additive for plaster or masonry composition. It is kneaded into a cement-sand mixture (about 20% of the total mass). Can serve as a base for paint.
Primer (impregnation). In proportions 1:1:2, cement, Cemmix Liqui and water are taken, after which they are kneaded. Next, the mixture is applied to the surface. It reduces dusting, binds the upper particles of the base, protects against water, external negative influences.
Impregnation for concrete mix. Portland cement, sand and liquid glass are taken in proportions of 1:1:1, mixed and applied to concrete. If you create a seamless coating, you can get waterproof protection for the building. With the help of this impregnation, small cracks are often closed.

Also, the composition of Liqui is often used as an antiseptic, mixing with water 1: 1 and for processing buildings (stone, plaster, concrete), after creating a mixture with water in a ratio of 1: 2.5.

Video: polyurethane-based concrete impregnation

The cleaner is not a concrete additive in its usual form. It is used not to mix the substance into the solution, but to soften it after hardening. Thanks to the active acid components in the composition, the concentrated cleaner quickly removes concrete residues from any surfaces. Used in the following cases:

it is necessary to destroy salts, rust;
it is required to remove plaque, efflorescence from brick or other building material;
construction tools need to be cleaned.

Summary table of properties

In the Cemmix catalog
Appearance	clear liquid
Density	1.04 kg/dm3 (at 20°С)
The basis	Acid
Dosage per m2	large residues of the solution: concentration - 1:1, or 50-100 ml old efflorescence, pollution: concentration - 1:3, or 400-500 ml limescale, rust: concentration - 1:5, or 200-300 ml
Packing	1 liter, 5 liters
Technical documentation	TU 2499-007-90557835-2014
Compatibility	Incompatible with concrete additives (destroys them)
Disposal	According to local regulations. Do not pour into water, soil, sewerage.

Application

Most cleaners are acid-based, so they work about the same. The composition includes the following components:

acid, which is responsible for the destruction of concrete;
active inhibitors that prevent the occurrence of corrosion;
substances that give protection to the metal.

How to use

Use the product with caution and be sure to wear gloves. It is also advisable to find a respirator and goggles. Then follow the instructions:

Remove excess dust and dirt from the area of application and remove by hand pieces of mortar that can be separated.
Using a sponge or brush, apply the cleaner to the concrete.
Wait 10-15 minutes (the exact time is indicated on the packaging of your product).
After the appearance of foam, wash it off with water. It is best to use a hose so as not to come into contact with acid. Repeat the process until you are done cleaning.

Video: CemClean concrete, brick, stone cleaner

Supplements that are made at home

There are hundreds of different mixtures on the market today that can improve the properties of a concrete solution. But until recently, those who built houses themselves found the most original solutions to make the foundation or walls stronger. Let's mention the most interesting or popular:

in the old days, eggs were thrown into the lime mortar to ensure the adhesion of the components and make the mixture more dense. When concrete was invented, it was also mixed with chicken eggs. The fashion did not last long, now, of course, no one does that;
the second old recipe is still in use by some experimenters. They add clay to concrete. Experienced builders know: such a solution is not suitable for the foundation. Is it possible to put a mini-shed;
soap or Fairy can be added to the concrete solution. They make the mixture more plastic;
the frost resistance of concrete increases ordinary salt. The main thing is not to put too much - no more than 2%.

These and other additives have practically gone out of use, because in stores you can buy high-quality additives tested in laboratories and at large factories with a guaranteed effect. But, the soul asks for experiments, you can try. But do not use such concrete for a house or other important buildings - it is dangerous.

Video: do-it-yourself frost-resistant concrete

Summary table of additives and their properties

For your convenience, we have preparedsummary table of additives and their properties . All product specifications and features are for CEMMIX products. In the table you will see the type of additive, its name in the catalog, a brief list of properties, type of work where it is used, consumption, minimum and maximum price.

0.02 - 0.03 Water demand reduction

Additive type	In the CEMMIX catalog	0,02 - 0,04 0,03 - 0,06
			Strengthening increase	Repair solutions
Reduced water demand	Masonry mortars
Increase in final strength characteristics	Reinforced concrete products
Increased bond with rebar	Ready-mixed concrete
	Improving waterproof performance

Proper use of additives for concrete mixture can significantly change the characteristics of the source material. This simplifies construction work, allows the use of concrete in non-standard conditions, and improves its properties. But it is very important to choose and use supplements correctly, only in this way they will reveal their 100% benefits.

Not sure what to buy or have questions about how to use it? Write or call us, detailed consultations are our forte.

Additives in concrete (additives, premixes) today occupy a fairly large and independent branch of construction chemistry and the demand for these materials is growing every day. Concrete is a very strong material of artificial origin, widely used in construction to build various structures, whether it is a surface, underground or underwater structure. Since all structures are subject to special safety requirements, in each individual case it is necessary to ensure that concrete structures are resistant to damage and the effects of both water and various aggressive environments.

In order to improve its properties and physical and technical indicators for some specific tasks, various additives and additives to concrete are used in the preparation of the solution. They not only improve the properties of cement mortars, but also simplify or reduce the cost of the technological process of preparation, and also allow transporting ready-mixed concrete over long distances without reducing brand strength.

Take, for example, concreting at low temperatures. Since the solution contains water, concreting work in winter is much more complicated. Thanks to additives that can be used in winter to lower the freezing point of water when preparing concrete or cement-based mortar, this problem is eliminated quite easily.

There are also types of additives that can speed up or slow down the setting of the mortar, which can help when working on large construction sites.

Separately, I would like to single out a group of reinforcing additives - fibers and fiberglass. These are materials made from various materials in the form of fibers of a certain length, usually from 3 to 60 mm, allowing in some cases (concrete floors, cement-sand screeds, platforms, blind areas, castings, etc.) to completely abandon the use of reinforcement in concrete. In other cases, in addition to a significant increase in the impact strength of concrete and bending strength, fiber fibers also take on the main risks in the transportation of finished products, and therefore the fiber is widely used in the production of cellular concrete. These additives reinforce the entire matrix, preventing shrinkage microcracks from appearing.

Classification of additives in concrete and mortars

Modifiers can be grouped by the main effect of the action:

Complex and plasticizing additives that correct the basic properties of concrete mixtures (reduction of water separation, increase in mobility, prevention of mixture stratification)
Accelerating or slowing down the setting of concrete
Increasing the density and water resistance of concrete (waterproofing additives)
Air-entraining and foaming
Imparting special properties (anti-corrosion, water-repellent additives)
Reinforcing (steel, polypropylene, fiberglass and basalt fibers).

In order to achieve several goals at the same time (for example, when the task is to accelerate the set of strength and increase the mobility of the mixture), complex additives are used that include several components. At the moment, there are a huge number of different complex additives that can improve the physical and technological performance of concrete. Our catalog contains all types of the above additives in concrete.

The use of concretes and their solutions in construction is widespread. This is the most popular material. Concrete is obtained from a mixture of:

sand;
cement;
crushed stone (gravel);
water.

The quality of concrete directly depends on the quality of sand, crushed stone or gravel and cement.

The quality of concretes and derivative solutions directly depends on the direct characteristics and quality of each component. Compositions are usually evaluated according to such indicators as average density, tensile and compressive strength, water, gas and air tightness, frost resistance, durability, etc. However, the main components are not always able to provide the required characteristics of the mixture, especially if the needs are very specific nature (underwater construction, buildings in places with a harsh climate, airfield pavements, storage areas for petroleum products, etc.).

Therefore, in order to improve existing indicators and impart new properties in construction, the use of additives in concretes and mortars is widespread, which significantly expand the scope and possibilities of using concretes and mortars.

The use of complex additives makes it possible to increase the density and strength of concrete, its water resistance and frost resistance.

Additives are usually divided into the following types:

superplasticizers;
to maintain mobility;
accelerating set of strength;
modifiers;
for frost resistance;
for self-sealing compounds;
complex.

This classification covers only the most common types of additives in concretes and mortars, today there are just a huge number of them, from different manufacturers and for different purposes. The properties of additives in concretes and mortars can be unique, or they can improve several characteristics of concretes and mortars at once. Additives are powder, granular or liquid substances. They can either be part of the mixture or cover the already hardened composition, qualitatively changing its properties. Additives are an effective and inexpensive way to improve the quality of the mixture, reduce the cost and speed up construction.

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Action of additives

Thanks to the use of superplasticizers, the quality of concrete improves in various ways: its strength, corrosion resistance, water resistance, frost resistance increase, plasticity increases, the consumption of binders decreases, as well as deformation and shrinkage processes are minimized and the service life of concrete structures as a whole is increased.

Superplasticizers are designed to increase the mobility of the mixture and give additional strength, density and water resistance. They are used to reduce the consumption of cement, but at the same time provide the necessary structural strength. To increase the brand strength of the mixture or increase the rate of curing at the first stages of hardening, special accelerators are used.

If long-term transportation of the mixture is required, or if the weather is especially hot outside, special additives are used to maintain the mobility of the composition. The antifreeze additive is relevant in winter or at low temperatures, up to -25 ° C. By adding it to the solution, you can safely carry out construction work. Modifiers make the compositions more durable, resistant to corrosion, frost. At the same time, the mixture retains increased mobility and reduced permeability.

For pouring thin-walled and densely reinforced structures, an additive for self-compacting concrete is very convenient. Complex additives greatly simplify the selection of several necessary components: there is no need to look for one manufacturer or have a good understanding of chemistry in order to ensure the most effective interaction of the additive components.

When working with concrete admixtures, it is very important to follow the manufacturer's instructions, in particular regarding the required proportions.

It is important to carefully follow the recommendations of the additive manufacturer, to avoid imbalances or violations of the stages. Sometimes the optimal dosage of additives in designs can be established experimentally when selected. Remember that the amount of hardening accelerators, sealing additives and steel corrosion inhibitors, including those included in complex additives, cannot exceed 1.5-3% of the mass of cement. Additives do not increase volume and are not the only success factor. Concrete still needs to be mixed correctly in proportion to a homogeneous state, and then laid and cured according to technology.

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Polymer and waterproof additive

Polymer additives introduced into concrete mixtures increase the plasticity of concrete, improve water and air tightness and frost resistance, and also increase the strength of solutions.

Polymer additives act as surfactants. They are designed to improve the quality of mortars and concretes. Some additives improve the plasticity of the compositions, reduce water separation, and reduce the need for water. This allows you to increase the strength of mortars and concretes. Under certain conditions, polymer additives can form a material with a spatial structure.

Thus, polymeric additives during HTT are able to pass into a fluid-viscous state. At the same time, they clog the pores of concretes and mortars, increase the adhesion of aggregates and cement. In this state, polymer additives improve a number of physical and mechanical properties of concretes and mortars: water resistance, tensile strength, air tightness, frost resistance and gas tightness.

A waterproof concrete additive is used in the manufacture of concrete waterproofing, as well as to increase their strength, frost resistance and increase water resistance.

Other polymer additives, which are called organosilicon, have the ability to release gas in the mortar or concrete mixture, so they contribute to the entrainment of air. Together with the property of partial hydrophobization of the surface of capillaries and pores, this makes it possible to increase the frost resistance of mortars and concretes. Additives that increase the water resistance of mortars and concretes act due to clogging of capillaries or other loose sections, larger than 1 micron. Moisture migrates through them. Waterproof additives improve the structure, increase the density of the cement stone. To determine the effectiveness and rationality of the use of waterproof additives, the difference in the cost of work without the use of additives, the saved cement and the additives themselves is taken into account. To calculate the technical and economic efficiency, the cost of saved cement and the difference in the price of conventional mortars or concretes are determined.

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Frost-resistant additive

The frost-resistant additive is used for work in the winter and provides a quick set of concrete strength and long viability of the concrete mixture.

Negative temperature is harmful to ordinary concretes, mortars and other stone materials, under its influence they can collapse, because when water changes from a liquid state to a solid state during freezing, the volume of water increases and significant efforts are developed. The effectiveness of materials resisting the effects of these forces is called frost resistance. Frost resistance depends on the density of solutions and concretes, strength, the presence of completely or incompletely filled pores. Ice can be placed in such pores without creating pressure on the walls, or with less force acting on the walls of the pores.

The most effective additives for increasing frost resistance are additives containing surfactants. Plasticizing additives such as SDB have a beneficial effect on the frost resistance of mortars and concretes, as they form an optimal structure. Optimum under such conditions is considered not microporous, but a dense structure, which slows down the process of setting the cement paste and contributes to more complete sedimentation. Sometimes, plasticizing gas-forming and air-entraining additives are introduced into the solution, which form spherical micropores in the compositions, which increase the frost resistance of solutions and concretes.

The proper effect of additives is observed only with strict adherence to the proportions and recommendations of the manufacturer. If you add a little frost-resistant additive to the composition, then the concrete will begin to freeze at sub-zero temperatures. This means that cement stone will not form. When the temperature rises, the hydration of the cement will be restored again, but the structure of the mixture will undergo significant changes, which will inevitably affect the strength of the structure in the future.

In order for the concrete structure to receive increased strength, it is recommended to use special materials that are added directly to the prepared cement-sand mortar. When hardened, the mixture, to which the concrete hardener was added, acquires many more useful characteristics that contribute to its longer service life. In addition to strength, they can also include water resistance, corrosion resistance, etc.

Application

As a rule, additives in concrete, which are needed to increase its strength, are not always used. The use of such materials is permissible in the case of:

the presence of high requirements for concrete or reinforced concrete structures for water resistance or frost resistance;
application in the solution of non-standard aggregates such as fine sand;
the manufacture of concrete products that will be subject to a high load (for example, paving stones made of heavy or fine-grained concrete);
erection of monolithic structures in which mineral expanding additives are used.

Classification and characteristics of additives

Strengthening mixtures, concrete additives are specially prepared chemical products. They are added to the design or product during preparation and solidify along with the main materials.

The main advantage of additives is the complete protection of the entire concrete by volume. And the disadvantage is the inability to strengthen the already created structure (this function is performed by reinforcing impregnations intended for concrete).

The task of plasticizers, which are part of concrete solutions, is to increase their mobility. At the same time, it is possible both to increase the strength of the resulting concrete by 120-140 percent, and to give it the following properties:

frost resistance increased by 1.5 marks;
water resistance is 3-4 marks higher.

Also, the use of plasticizers reduces cement consumption by up to 25 percent, which saves on construction work.

Strength accelerators are characterized by an increase in the rate of concrete hardening, as well as an increase in its grade strength. One of these substances is granular calcium chloride used in the manufacture of foam concrete, paving slabs, wall stones and polystyrene concrete.

With its help, the production process is accelerated due to less downtime of the product in a special form, and the number of products produced, respectively, increases. At the same time, concrete strengthening by several percent is observed. And on the products, the number of chips that worsen their presentation is reduced.

Among the useful qualities that a concrete hardener with an antifreeze effect adds to the material is not only an increase in strength, but also the elimination of the influence of low (up to minus 25 degrees) temperatures on the solidification process.

One of the most popular substances of this type is a neutralized resin used in conjunction with water repellents (for example, Sofexil-gel and Tiprom-S).

Another advantage of the additive is to improve the ease of handling of the mixture.

In addition, the resulting product becomes waterproof (and thus does not require waterproofing). And when transporting the solution, its stratification noticeably decreases.

Concrete mortar modifiers

Modifiers are an additive to concrete to increase strength, which also increases the frost resistance and mobility of the composition. There are modifiers that can improve the anti-corrosion properties of concrete.

Complex additives

Complex additives to increase the strength of concrete provide additional positive effects. For example, some substances increase the workability of concrete, its construction and technical characteristics (water resistance and frost resistance), reduce the amount of water spent on preparation, and reduce cement consumption. At the same time, all components of the additive perfectly interact with each other.

Nuances of use

Knowing how to increase the strength of concrete, which additive is best suited for the goals, it remains to figure out the correct execution of the work. First of all, the substance is diluted in warm water until it dissolves. If the additive is mixed with a sand-cement mortar in a liquid state, it begins to act immediately. Dry material requires some time for complete dissolution and mixing.

The calculated amount of additive depends on the dosage indicated on the specific material by its manufacturer, as well as on the degree of increase in strength that needs to be obtained. The recommended amount for plasticizers does not exceed 1% by weight of cement.

Other ways to harden concrete

Strengthening materials include not only those materials that are added to concrete during its creation to increase strength. When the design is already ready and cannot be replaced, other substances and other methods are used. The most popular in construction and repair work is the strengthening of concrete using liquid and solid hardeners. They are generally best suited for floors and other horizontal surfaces.

Liquid hardeners or impregnations contain water-soluble inorganic compounds. They are able to penetrate ordinary concrete (which was not previously treated with water repellents) to a depth of 3–5 mm. Inside the material, the liquid reacts with it, forming insoluble compounds that act as hardeners.

Such a hardening impregnation for concrete is applied both to old structures and to new ones, the increase in strength of which was not provided for during the manufacturing process. The disadvantage of impregnation is the impossibility of application in an aggressive environment. The advantage is giving concrete the ability to withstand stronger loads.

To strengthen concrete, you can also use a dry hardener, which contains cement. The structure, the strength of which has been increased in this way, can withstand up to 70 MPa. In addition, the strength of concrete for weak stretching and its wear resistance are increased.

The process of applying a dry hardener is not affected by the aggressiveness of the environment. However, it is applied (in a state diluted with water) only on a smooth and dust-free surface. At the same time, the service life of the structure is increased by at least 10–15 years.