More recently, concrete could only be one color - dull and gray. Today, thanks to advanced technological developments, architects and designers can use a concrete composition painted in any required color when constructing structures. Modern paints and pigments for concrete are used to paint a wide variety of surfaces. In this article, we consider the types of modern pigments for painting concrete surfaces, as well as the features of their use.
What it is?
Pigments for concrete are special powder additives, thanks to which you can give the necessary color to the solution or the finished concrete product. Such dyes after drying the painted surface do not dissolve in water, oil and other liquids. In addition, provided they are of good quality, they are quite resistant to ultraviolet radiation (sunlight) and rain washout. The pigment of each color has the ability to selectively reflect the flux of daylight. The coloring matter of a particular color absorbs and reflects only strictly defined waves of the visible spectrum.
There are only two exceptions: for example, white pigment for concrete reflects almost the entire spectrum of colors that fall on it, while black dye, on the contrary, absorbs most of the spectral waves.
Classification
The pigments used for painting concrete are classified by origin into:
1. Organic pigments :
- yellow;
- scarlet;
- red;
- blue;
- green;
- purple;
- pink;
- burgundy;
- artificial cinnabar.
2. Mineral - inorganic powder pigments for concrete.
- kaolin;
- iron minium ;
-
manganese peroxide;
- a piece of chalk;
- graphite;
- lime;
- Umbra;
- ocher.
- chromium oxide;
- soot painting;
- zinc crowns and greens;
- burnt umber;
- lithopone dry;
- painting blue;
- zinc, titanium and lead white.
3. Metal:
- golden bronze;
- aluminum powder;
- zinc dust.
To obtain natural dry pigments for concrete, various natural materials are mechanically grinded, and to obtain artificial dyes, mineral raw materials, for example, ocher, are subjected to heat treatment.
Modern dyes are available not only in the form of dry powders, but also in the form of emulsions, concentrated pastes and microcapsules.
Main characteristics
Depending on the chemical composition, the coloring pigment for concrete has characteristics such as corrosion and temperature resistance and color. The pigment composition has the following properties:
- Lightfastness - the dye will retain its original or close color under the influence of ultraviolet radiation. Natural pigments are most resistant to such effects.
- Hiding power - the ability of a pigmenting composition to apply its color to a surface when applied to a surface.
- Dispersion - depending on how finely the coloring pigment for concrete was ground. The finer the grinding and the finer the particles, the higher the coloring ability and hiding power of the composition.
- Chemical resistance to alkalis - pigment color resistance to the effects of alkaline environments of cement mortar.
- Oil consumption, which is understood as the ability of pigment particles to hold on the surface the required amount of a binder composition (oil). It depends on the origin and dispersion of the pigments. The lower this indicator, the more durable and economical this coating will be.
Painting methods
Today, two main methods of coloring concrete structures are used. One of them is the coloring of a concrete solution during its mixing, and the second is the painting of ready-made structures from this material. Let us consider in more detail each of them.
The method of painting at the stage of mixing the solution
According to most experts, the most uniform color of the concrete structure is obtained when a dye, a pigment for concrete, is introduced into the composition during the mixing of the solution. Due to this, the concrete surface becomes uniformly painted throughout its thickness and does not lose its attractive appearance as the upper layer abrases. Color saturation directly depends on the amount introduced into the pigment solution, the price of which is quite high, which determines the higher cost of colored concrete compared to traditional ones.
This method of painting is used for monolithic pouring of various street platforms, creating decorative and retaining walls, production of borders, paving slabs and pavers.
To obtain a beautiful and “pure” color, it is best to use white cement and sand to prepare the solution. To obtain the maximum effect, before introducing the pigment into the mixture, it is diluted in water to the consistency of “sour cream”, mixed thoroughly and left for several hours - to insist. Then, constantly stirring, the resulting composition is poured into the solution and thoroughly mixed.
As already mentioned, today you can buy pigments not only in the form of dry mixes, but also concentrated pastes, microcapsules and emulsions, which allows you to add pigment for concrete with your own hands and create a solution of the right color and in the right amount.
Painting of finished concrete products
For monolithic concrete structures and finished concrete products, this is the most suitable painting technique. A layer of a coloring composition is applied to the surface of already hardened structures, penetrating several millimeters into the structure of the material to be painted. How deep the dye penetrates depends directly on the carrier in which the pigment was dissolved.
In the role of a pigment carrier, various varnishes, colorless bases for facade paints and other water repellents can be used. The deeper the carrier manages to penetrate deeper into the concrete structure, the longer it will retain color and attractiveness under the influence of ultraviolet radiation and adverse environmental conditions.
Is it possible to make coloring pigments with your own hands?
Dyes made industrially have several advantages over independently made ones, however, it is quite possible to create a pigment for concrete with your own hands if desired and perseverance. To create such a dye you need:
- water-soluble pigment for paints;
- water-based primer for mineral surfaces;
- water.
In that case, if the primer is not concentrated, then from 20 to 30% water is added to the mixture. To obtain colors that are closest to natural, it is best to mix several pigments of the corresponding colors. It is important to remember that mixtures painted in this way, after drying, must be further varnished, as they do not have protective properties. To ensure resistance to moisture and sunlight, such processing is carried out every 4-5 years.