In order to give concrete additional properties, various substances and solutions are added to it. To ensure a faster tenacity, water resistance and moisture resistance, it is customary to add sodium or potassium silicate, which is called soluble or liquid glass. For concrete, it is used in the composition of the cement mixture necessary for waterproofing concrete surfaces. This article will tell you about the features of the material and the rules for its use.
The composition and scope of liquid glass in concrete
The phrase “liquid glass” is familiar to many, but not everyone knows what this mixture consists of and for what purpose it is used. An aqueous solution of potassium silicate or sodium was discovered by alchemists in the Middle Ages, but the first factory for its production appeared only in the 19th century. Then it began its widespread use in the construction industry.
The material is produced by fusing soda and sand or by combining the proportions of ground silicon with hot sodium hydroxide. At the exit receive translucent viscous substance of white or yellowish color, called liquid glass. The composition of the solution may include silicates of sodium or potassium, as well as their mixture.
A material with different properties is widely used in construction for waterproofing concrete surfaces. To this end, carry out the coating of concrete with liquid glass. A silicate solution is applied directly to the cement, which is absorbed into the surface. When the substance dries, all the pores of the concrete are blocked, protecting it from moisture penetration. The maximum effect is achieved by applying several layers of this composition.
This material is used as an impurity to the concrete solution. Concrete with the addition of liquid glass has a high degree of waterproofing, freezes much faster. Therefore, it should be used for a certain time. In addition, liquid glass is used to produce monolithic concrete blocks of different brands and different sizes.
The use of substances in different areas due to the advantages of the silicate material, among which emit:
- high degree of penetration and adhesion;
- the formation of a solid waterproof film on the surface of the coated material;
- small consumption of the substance in the solution;
- Reasonable price means.
The main quality of a concrete solution with the addition of liquid glass is that the mixture quickly sets and provides a high degree of protection against moisture. However, it should be noted that the strength of the monolithic structure then decreases.
Helpful advice! The use of cement mixture with the addition of liquid glass will allow you to successfully repair structures made of concrete, asbestos cement, ceramics, and even to carry out the restoration of cast iron pipes.
It is most expedient to use a silicate-concrete solution for such needs:
- sealing cracks with liquid glass in concrete, brick wall, to isolate joints;
- urgent repair of the concrete foundation, destroyed by excessive exposure to moisture;
- strengthening of concrete with liquid glass in the ceiling, for connecting beams and other elements.
In the cases listed above, liquid glass is added to the mortar in the proportion of not more than 1: 1. Then knead a little solution and immediately use it, since the mixture of cement and silicate dries very quickly. The correct ratio of substances will allow for a long time to eliminate defects or give additional strength to concrete structures.
The addition of liquid glass to concrete is appropriate when creating a foundation on the ground, where the soil contains a high level of acidic water. This ensures that the concrete is more resistant to the damaging effects of moisture. Successful casting of such a foundation is provided by the following rules:
- the addition of sodium silicate to the concrete solution should not exceed 3%;
- make additional and thorough waterproofing of the foundation with the help of other materials.
You can prepare a mixture of cement and liquid glass even at home, while observing a number of requirements. Violation of the technology of the mortar can lead to the formation of cracks in the concrete.
Liquid glass should be added to the dry mix. To do this, first in the right proportions combine all the dry ingredients and mix them thoroughly, without using water. Then gradually pour into the composition of liquid glass, previously diluted with water.
It is necessary to strictly observe the ratio of all ingredients in the preparation of the solution in accordance with the recipe used for a particular type of work. For example, if we are talking about the amount of glass in concrete, it should not exceed 25% of the total weight of the mixture. For the preparation of the primer using cement and silica glue, the ratio can be 1: 1.
Note that the acceleration of the speed and density of solidification of the solution is influenced by liquid glass for concrete. Instructions for use recommends to prepare the mixture in a small amount and use it quickly.
The setting time depends on the amount of liquid glass added to the concrete. If the mixture contains 2% of this substance, then it begins to set in an hour, if 5% – then after 40 minutes. The proportion depends on the process of solidification. If more than 4% silicate glue is added to the solution, the strength of the concrete after complete solidification will decrease by approximately 25%. However, if the concrete contains only 3% of liquid glass, the strength of the structure will increase.
Helpful advice! Sodium silicate, in addition to its waterproofing function, has antibacterial and anti-fungal properties. The chemical composition of the material is an inappropriate environment for the development of any life.
Liquid glass in a solution mixed in cement M400 at a temperature of 20 ° C, begins to set in 2-3 hours, and completely hardens in a day. Over time, the monolithic base only gets stronger. The maximum effect of hardness is reached in a maximum of 4 weeks. Liquid glass is also used as an impregnation of various surfaces, ensuring their smoothness, evenness and waterproofing. Concrete treatment with liquid glass is carried out for such structures:
- concrete floor;
- flat roof;
- swimming pools;
- concrete walls and ceilings.
The impregnation process involves several steps. First of all, preparation of the base is required. To do this, the surface is thoroughly cleaned from the old coating, paint, debris, dust and dirt. Next, carry out the cleaning with a metal brush, the base is covered with a bitumen emulsion with a layer of 2 mm. The basis of give time to dry.
Then, the surface is impregnated with a solution with liquid glass. The proportions of liquid glass in concrete depend on the type of surface (in accordance with the instructions for use). If the surface is horizontal, then a layer of 2-3 mm is applied on it and the mixture is smoothed with a spatula. Fill the floor and floors produce in several layers, making a break for a certain number of hours. You can use the surface after a couple of days.
During the work you need to follow a number of recommendations. In particular, the solution must be distributed evenly. Coating should be done as quickly as possible, not allowing the composition to harden. Reliable impregnation ensures the application of the mixture in two or even in three layers. To insulate the walls and ceiling use a special spray gun, which promotes uniform distribution of the solution. Cover the surface in two or three layers.
Liquid glass is used not only for priming, impregnation of surfaces, but also as a coating. For this purpose, a special solution is prepared that includes fine ground aggregate, sand, and active silica, water glass and water are added to it. The ingredients are mixed with a construction mixer. The resulting substance should be viscous and thick.
Solutions with liquid glass for a concrete floor are used for applying a protective waterproofing layer on floors, walls and ceilings in rooms with high humidity: in bathrooms, saunas, laundries, pools or baths. It is also recommended to use these mixtures in the basement.
Before applying the water glass on the concrete, the surface to be treated is thoroughly cleaned and leveled. As a topcoat, liquid glass is used as a strong hydrophobic solution. Surface coating is carried out by pouring on the screeds, which are formed by slats installed parallel to the wall.
Helpful advice! Liquid glass has a high thermal conductivity. Therefore, the material is often used to provide additional thermal insulation. Adding liquid glass to concrete in the right proportions ensures high thermal insulation of the surface, which can withstand temperatures up to 1200 ° C.
The quality of work depends on the uniform distribution of the material. This can be done with a special needle roller, trowel and squeegee with an extended handle. The size of the layer is 2-4 mm. Given the short drying time of liquid glass on concrete, the work must be carried out fairly quickly. To do this, it is better to divide the covered area into areas, and the whole process – into several stages. After preparing the floor surface, concrete is painted with liquid glass.
Depending on the purpose of using liquid glass, proportions are made. The main thing in this business is responsibility and accuracy. The universal impregnation recipe provides for a mixture of silicate and water in a 1: 2 ratio. There are several options developed by experienced builders that are time tested.
If the silicate solution is used as a primer, the mixture is prepared in proportions of 1: 1 (with cement and adding the right amount of water). That is, in 1 kg of cement add 1 kg of liquid glass and gradually pour in such an amount of water that the resulting mixture was convenient to prime the surface. In the case of rapid hardening of the solution, you can add a little water after a while.
For the waterproofing of wells, liquid glass is combined with carefully sifted sand in a ratio of 1: 1. The resulting mixture covers the walls of the well.
In underground concrete premises, reliable hydroprotection will be ensured by the addition of liquid glass to concrete in the following ratio: 1 l of silicate adhesive per 10 l of cement mortar. This composition ensures reliable insulation of the walls and floors of basements located underground. The refractory mixture is prepared as a cement-sand mortar with the addition of a small amount of liquid glass.
Wood preservatives are obtained in this way: they mix liquid glass with water in equal proportions. In this case, a slippery protective film is formed on the tree, which is not subject to painting. For this reason, this solution is not recommended to be applied on concrete walls.
Various types of impregnation are prepared, mainly based on the following proportions: 400 ml of liquid glass per 1 liter of water. The next layer is applied in 20-30 minutes – after exactly such a period of time as the liquid glass on the concrete dries.
The use of liquid glass to waterproof and reinforce concrete is the most effective and optimal solution both in terms of technology and in terms of price. The main condition is compliance with the application instructions, which regulates not only the order of work, but also strict compliance with the proportions of materials. Sodium silicate mixture is better to enter into the solution, and not to use as a separate painting material.
The use of liquid glass for external processing is considered the most budgetary option, but in aesthetic terms, such a coating is significantly inferior to the more expensive counterparts. If it is necessary to impregnate the concrete with minimal cost, liquid glass is the best solution.