What is a foaming agent for concrete and how to get it

Cellular structure of foam blocks provides a number of properties that invariably attract the attention of developers, including the private sector. A component such as a foaming agent is necessarily involved in the production of foam concrete, because without it, cellular concrete is not formed. The article will tell about what it is in more detail.

Foaming of the construction mix consisting of cement, sand and water occurs just due to addition of a frother in it. The mechanism of the process will look as follows - air bubbles formed as a result of a chemical reaction, very quickly loosen (foamed) the mixture, which leads to the creation of a gas silicate.

Due to the increased air content in the final product, foamed concrete has such properties as low weight and heat and sound insulation. In addition, for the processing of foam can be used quite affordable simple tools, such as a saw. Unlike denser concretes, for the dismantling of which it is not uncommon to cut reinforced concrete with diamond circles.

The composition of the material and its types

Universal frother not found until now. A similar property of a fluid is provided by the addition of surfactants to it. For pure water, soap can act as such an additive.

It is formed by the reaction of alkali with vegetable or animal fat. It is known that sodium soaps have a solid consistency, and potassium soaps - liquid. Beginning masters in the production of foam concrete try to take the last one as the basis for the foaming agent, but in such cases literally everyone fails.

Why? The answer lies purely in the chemical plane: the cement contains a large amount of calcium salts, ions of which take the place of potassium and sodium ions and form insoluble compounds. The foam produced at the beginning of the process quickly disappears.

However, if pitch or naphthenic acid is taken as fat replacement products, the reaction will produce soap, the foam of which in the presence of calcium will not settle, but increase in volume. Here is a component is the basis for the foaming agent in the case of its manufacture in an artisanal way, or with your own hands.

Created on an organic or synthetic basis, frothers differ in properties. With the use of the second foam concrete is obtained less quality and durable, but it is cheaper and simpler in its production.

Gas silicate, where protein foaming agent was used for foam concrete, is much stronger because the solution binds more actively to the foam, and the inter-bubble partitions are thicker and more reliable. From an environmental point of view, such material is cleaner and safer.

Industrial Frothers

In the production of foam used a huge amount of blowing agents (as we have said, there is still no universal option). They all differ to some extent from each other, but their common purpose is to form a stable foam in the production of foam concrete.

Any option must meet the following requirements:

1. Technical and economic indicators. The price of the spent frother in dollar equivalent should not exceed $ 2 per 1 m³ produced gas silicate. Otherwise, the cost of the final product rises sharply, and the use of a frother at an inflated price becomes economically unprofitable. It should be noted that a direct relationship between the cost of the material and the quality of the products is not marked.
2. Chemical properties. Regardless of the batch and the date of issue of the blowing agent, it must have constant and unchanged chemical properties. If the characteristics change, the whole process chain is lost and its constant adjustment is required, which leads to an increase in production time and a decrease in product quality.
3. The material must have a long shelf life.usually at least 1 year. If you buy a frother with smaller parameters, you have to do it in small batches, which, again, is not economically feasible.

1. It should have a small specific consumption.. Set frother consumption per 1 m³ produced foamed concrete should not exceed 1.5 liters. This value was determined empirically and it is not recommended to exceed it in order not to influence the setting of the foam concrete, and it is optimal for a single load of the foam generator.
2. Have a simple compositioni.e. It should not be multi-component.

Tip: do not use a large number of components in production, this leads to complication of the process of obtaining a working solution and reduces the accuracy of their dosing.

Frequency and durability

These parameters are the basic physical properties of the technical foam.

They are directly dependent on the type of frother and device of the foam generator.

1. The physicomechanical properties of porous concrete depend on the multiplicity and durability indicators.
2. In accordance with the sanitary and hygienic requirements, the value of the foaming agent multiplicity must be at least 10.
3. According to the GOST 12.1.-007-76 classification, frothers belong to the 3, 4 class of low hazardous substances and must meet the requirements of radiation and sanitary hygienic safety. These are non-toxic and non-explosive substances.
4. In terms of biodegradability, the requirements for foaming agents coincide with the requirements for the use of surfactants in the production of building materials.

The second most important indicator - resistance, it shows the coefficient of resistance of the foam. The indicator of the stability of the foam in the cement paste is determined and applied mainly in laboratory conditions. Under production conditions, the term “foam utilization ratio” is often used.

Temporary resistance of the mixture

The value of this parameter is also an important characteristic of the technical foam and is determined by the draft of the foam concrete mixture over time. The better the foaming agent is, the higher is the durability of the concrete mix and, accordingly, the higher the quality of the final product.

Thus, for the initial evaluation of the foaming agent, it is necessary to take into account the parameters of the multiplicity of the foam and the coefficient of resistance of the foam, as well as the concentration of the foaming agent to create a stable foam. These indicators are the main criteria for evaluating the material.

Self-receiving frother

In some cases it will be advisable to get the foam concrete blocks in artisanal conditions, that is, independently. This process will cost the developer of foam concrete houses cheaper than purchasing the finished material.

An important aspect is that you can get blocks of the sizes that are required, you only need to prepare a formwork with the required dimensions. Frother in this case is not difficult to make.

Tip: to create communication channels through the blocks, you do not need diamond drilling holes in concrete, it is enough to use conventional drills.

Technology

Its basis will be rosin soap. Gum rosin is treated with alkali, and for viscosity, joiner's glue is added to the system.

To obtain a foaming agent (based on 1m³ foam concrete) required:

• caustic soda - 0,016 kg;
• Rosin - 0.06 kg;
• wood glue - 0.063 kg.

Receiving takes place in several stages:

1. Cook soap, finely crush the rosin, sift the loan through a sieve, the maximum allowable size of the pieces is 5 mm. Dilute caustic soda with water to a density of 1.2 kg / m³, bring to a boil and gradually add all rosin (1 l of solution requires 1.5 kg of rosin). Boil the whole mixture for about 2 hours.

1. Crush the glue in advance into small pieces and soak them in water for a day at a ratio of 1:10. Then heat the composition to 60? C and mix until dissolved.

1. Add the cooled soap in the adhesive mixture in small portions with the necessary mixing. Ratio: 1 to 6.

Recommendations

1. As already mentioned, calcium soap should not be used for the production of a foaming agent: a lot of foam is obtained, but the quality of the blocks obtained will cause the master to be upset.
2. The instruction advises to check the foaming agent; a small amount should be poured into any dish and turned over. Composition of proper quality should not fall out of the tank.

Tip: to obtain high-quality foam concrete, you need to take a frother in the amount of 0.7 - 1.4 liters per 1 m³ prepared cement mix.

Conclusion

From the article you learned what a frother is, what characteristics and properties it should have, and also found out which frother is better for foam concrete. The technology for independent production of material was also disclosed so that blocks could be made at home. The video in this article will help you find additional information on this topic.