Properties of mortars for bricklaying and technology for their preparation

Before deciding on the masonry, first of all, you should carefully evaluate your budget, because it is one thing to buy bricks and quite another to choose a masonry mixture. It may be more expensive than the bricks themselves. Often people choose the cheapest option, but it doesn't always work. To choose a solution for your needs, you should learn more about the types of mixtures, how they differ, what are their pros and cons.

There are several options for masonry mixes. The most commonly used cement-based mortar, which is also called sand-cement. In addition to masonry, it is perfect for rough plastering as well as for concrete floor screed. It all depends on the consistency. A thicker mortar is suitable for masonry, it will not spread during work and will not leave smudges, and the masonry will be even and neat, the bricks will not move.

There are quite a few disadvantages of the cement mortar, the main one is its strength. After drying, the mixture has a high rigidity, during the shrinkage of the structure, in which the frame is made of concrete, or thermal expansion, the masonry can burst, thereby reducing the strength of the structure.

The cement mortar is characterized by low mobility, which is not very well manifested in the process of masonry construction. The mobility of the mixture is determined by the factor of its spreading over the surface under its own weight. Mobility can be reduced or increased by adding components to the mixture. This property allows vertical and horizontal joints to be filled evenly.

Lime mortar, in contrast to cement mortar, is more plastic and warm. But it is much less durable and therefore it is rarely used for laying walls that bear a heavy load, it is more intended for low-rise buildings. It is mainly used in dry rooms. Lime mixtures dry longer, which increases the time from masonry to finishing work. Such solutions are rarely recommended.

Cement-lime mortar is a kind of golden mean. It is quite durable, flexible and warm, which allows it to be used for almost all types of masonry. It is easy to apply, which increases the speed of work. Suitable for building walls in dry and damp rooms. Withstands heavy loads and is suitable as load-bearing structures.

Along with the above, a cement-clay mortar is often used, it sets faster than a cement-lime mortar. Great for use in areas with low temperatures. Possesses sufficient ductility and strength.

In addition, there are ready-made dry mixes on sale that you just need to dilute with water in the right proportions. They have all the necessary properties for different types of masonry. Such mixtures are much easier to use, but their price can be much higher than the cost of the same amount of a solution prepared on our own.

Among the ready-made solutions, you can find colored masonry mixtures. They are intended for decorative masonry, but have a sufficient margin of safety and protect the masonry from damage.Such mixtures are resistant to frost and moisture, as they are often used for cladding buildings. The market offers a large selection of colors and shades of the mixture, it can be easily selected for any need.

A color mixture can serve two purposes. In one of the options, a monochrome shade is required and the mixture should not stand out against the general background of the masonry, therefore it is selected to match the main color of the brick. In another option, it is necessary to highlight the structure of the brickwork and the color of the solution is selected contrasting. In such cases, a white solution is often used. There is an opportunity to choose a color for any need.

There are also heat-resistant mixtures. They are used for laying stoves, fireplaces and chimneys. Such solutions do not deform when heated and do not lose their properties.

The proportions of any type of solution are calculated based on the load that will fall on them. The composition of the cement slurry includes cement and, as a rule, quarry sand. It initially contains a small percentage of clay, which adds plasticity to the solution. For these purposes, river sand is not suitable due to its coarse fraction and a large amount of impurities - it has to be carefully filtered. Cement acts as a binding element, the more it is, the stronger the result will be after drying. This is also influenced by the brand and freshness of the cement. Over time, unused cement tends to deteriorate.

For masonry, the ratio of cement to sand should be 1/3. Since the mortar is suitable not only for masonry, the proportion can vary from 1/3 to 1/6, depending on the type of work.

Cement-lime mortars consist of cement, hydrated lime, sand and water. As a rule, the proportions are 1/1/6 (cement, lime and sand). The recipe for such a solution is quite simple, it is prepared according to the same principle as lime. Such solutions can be used for plastering work.

The composition of the finished masonry mortar can be different depending on the type of material from which the brick is made. Basically, it consists of a binder, which can be cement or lime, as well as a filler and a plasticizer - these are most often sand and clay. In some cases, the composition of the mixtures may contain special additives to increase the drying rate or frost-resistant for work at low temperatures.

The proportions, as a rule, are indicated on the package in the ratio of water to the mixture itself. In the production of such mixtures, all ingredients are brought to a homogeneous mass, ground and packaged in packages. The consumer can only follow the instructions.

To obtain colored solutions, the necessary mineral pigment is added to the mixture. They are not subject to fading. The mixture can be colored on request. Otherwise, these solutions differ from the previous ones only in their cost.

Heat-resistant mixtures are created on the basis of cement, lime or clay. In some cases, the base may be gypsum. They have a number of special additives, the cost of which may be too high for self-preparation of the solution.

Due to the high cost of ready-made mixtures, the task often arises to prepare them yourself. for heat-resistant solutions, the components can be sand and clay. The clay is resistant to high temperatures. The main criterion is its fat content, the use of non-greasy clay is contraindicated, the excess of fat content can be compensated for with sand. From this type of mixture, the body of the furnace should be laid out.Facing is best done with a cement-based or lime-based mortar. The use of colored masonry mixture is allowed.

Preparing a mortar for brickwork is usually not difficult. Most of the components are commercially available. The easiest way is to prepare a cement mortar. In appropriate proportions, the mixture is brought to a homogeneous composition, after which it is necessary to dilute it with water and mix to a viscous mass. It is important not to pour too much water, as the mixture will turn out to be too thin, which will complicate the masonry process and will leave smudges. In addition, the grout will reduce the strength of the structure.

Lime mortar is prepared on the basis of lime dough, which you can prepare yourself from quicklime or buy ready-made. For cooking in the above proportions, knead the lime dough and sand. Then dilute everything with water. It is important to choose the right consistency, it should resemble sour cream in density.

To prepare clay solutions, it is necessary to check the fat content of the clay. To do this, the clay must be diluted with water and mixed with a smooth board to the consistency of sour cream, and then estimate the amount of clay remaining on the board after removing it from the solution. If the clay layer is too thin, about 1 mm, then it is considered skinny and unsuitable for masonry.

A thick layer means the clay is too oily and should be thinned with more sand than usual. Clay is considered optimal if its thickness on the board is 3-5 mm with small clots. The clay is mixed with sand, diluted with water to the consistency of sour cream and then ready for use.

Consumption rates of masonry mortars are calculated based on the thickness of the walls being erected, the size and type of brick. Solid brick will require less mortar than hollow brick. And also on walls made of bricks of large sizes (one and a half, double), a smaller amount of mortar will be required than on the same wall made of single bricks. Consumption is usually calculated for 1 sq. m and 1 cubic meter. m.

Consider an example with cement mortar. If we talk about the thickness of the wall, then there are several types of masonry:

• in half a brick;
• in one brick;
• in two bricks;
• in two and a half bricks.

A standard single brick has dimensions of 250x120x65 mm. One cubic meter of them fits about 400 pieces. Using a brick of this size, with a seam thickness of 1 cm, approximately 0.3 cubic meters will be required. m solution, given the small margin. In terms of 1 sq. m of brickwork, the volume will be about 75 liters of mortar. Subtracting water, which, as a rule, is 25–35% of the total amount of the solution, it can be calculated that the consumption of cement per 1 sq. m of masonry will average 33 kg.

In accordance with the proportions of 1/3 of the sand, you will need about 100 kg. The amount of building material consumed may differ depending on the original components from which the brick was made.

At the moment, there are online calculators that will help you make a more accurate calculation. And also in any hardware store will provide a full consultation regarding the consumption of a particular mixture. It would be useful to take advice from a professional bricklayer. A good professional will explain a lot of aspects related to masonry. Manufacturers of bulk materials always indicate the consumption on the packaging of their products. It is recommended to buy the components of the mixture with a stock, as the construction site is full of unforeseen situations.

For tips on how to knead brick mortar, see the next video.