Concrete proportions for blind area: calculation, features, composition and recommendations

The blind area is a rather important architectural element of the building. Therefore, when it is poured, certain technologies must be observed. First of all, it is important to prepare the solution correctly. If the proportions of concrete for the blind area are not met, it will not last long in the future.

Appointment

The main function of the blind area in the building is, of course, to protect the underground part of the basement from rain and meltwater. The arrangement of this architectural element, thus, can significantly extend the life of the base of the house. If the land near the basement remains dry, among other things, the load in spring will decrease, during the puddling of the soil. Sometimes in the building the blind area also performs one more function - it serves as a footpath. If the house is adjoined by a lawn, it is also very convenient to water from it.

Requirements for stand

When constructing this architectural element of a building, the following SNiP standards are observed:

• The width of the footprint for class I ground must not be less than 1 m, for Class II - 2 m.
• The maximum thickness of compacted soil under the concrete belt is 0.15 mm.
• The minimum slope of the blind area is 0.03 m.
• The thickness of the sand cushion under the belt should not be less than 3 cm.

In the process of pouring, the blind area is necessarily reinforced using a metal grating. To arrange the drainage layer, crushed stone should be used.

From what quality of concrete can depend

Some owners of country houses believe that since this element of the building structure does not carry any special load during the operation, it can be used for it, even not a very good mixture. However, this is not the case. The proportions of concrete for the blind area must be observed. Indeed, when it is destroyed (the appearance of cracks and chips), the foundation of the house immediately begins to be exposed to moisture. As a result, the life of the building as a whole is significantly reduced.

According to the norms of SNiP, for this architectural element of the house it is allowed to use a concrete mortar of the brand not lower than M200, which corresponds to class B-15. In order to prepare such a mixture, you should choose the right cement, sand and filler. And, of course, they need to be mixed in the right proportions.

What brand of cement to buy

This component determines to what extent the quality of the concrete for the blind area will be of high quality. The proportions of the remaining components are determined mainly by the amount of cement. For a concrete mix of class B-15, it is necessary to choose material of grade M400. Such cement is characterized by the following technical characteristics:

• The setting time is 2-4 hours at an air temperature of +18 ... +22 ° С.
• The operating temperature range is -60 to +300 ° C.
• The service life of structures is up to 100 years.

Ready-made concrete grade M200, manufactured using cement M400, practically does not pass water, is amorphous with respect to most types of solvents and is not afraid of sudden temperature changes.

What should be the filler

The proportion of concrete for the blind area of the house must be observed, but it is equally important to choose the correct filler for the mixture. This element in the solution serves as a kind of "armature" that takes on all internal stresses. It is allowed to use gravel or crushed stone as a filler for a mortar intended for paving. If you want, you can replace these elements with a small rubble stone.

How to prepare sand

The strength of the concrete mix depends, among other things, on the quality of this component. Sand in this case it is better to take a large river. But, of course, the opportunity to purchase such material is not available to all owners of country houses. If you can not buy river sand, you can replace it with a quarry. However, before mixing the mixture, this material must be sifted through a grid with a 2-3 mm cell. Perform this procedure better in windy weather. In this case, the fine component (dust) also separates from the sand.

How to add water

Dilute the concrete mixture in such a way that it becomes sufficiently plastic and it was convenient to work with it. Water in the grout should be warm. You can use a conventional well or well. It is allowed to take water from the dacha storage. But in this case it should be ensured that it is clean.

In the end, the diluted solution should not drain off the shovel. Do not make the mixture and it's too thick. If it crumbles or sticks to the shovel in large pieces and it is difficult to clean it off, it should be diluted a little. After mixing, a good solution with water separation is not split.

Concrete proportions for blind area: calculation

Of course, to prepare a quality solution, you should not only choose the right materials, but also mix them correctly. The proportions of concrete in this case are usually as follows:

• Cement - 1 part;
• Sand - 3 parts;
• Rubble - 4 parts;
• Water - 0.5 parts.

Thus, the proportions of concrete for the blind area in buckets are usually determined. For wide tapes, it is better to make a stronger mixture, adding three buckets of gravel or crushed stone to it on a bucket of cement. When pouring a tape around a farm building, you can, on the contrary, save on material and use not three but four pieces of sand.

Calculating the proportions of concrete for the blind area, one can take into account, among other things, the fact that 280 kilograms of cement, 1.4 tons of crushed stone, 840 kg of sand are used to prepare 1 m ³ of M200 grade solution. All this is poured into 190 liters of water.

Recommendations for kneading

Thus, we found out what proportion of concrete for the blind area is the most suitable. But, of course, to get a quality solution at the outlet, it must also be properly mixed. Cooking material for pouring blind area is using a concrete mixer. In this case, it will be much better. The concrete mixer must be placed on a flat surface before starting work. Components in it fall asleep in the following sequence:

• cement;
• sand;
• Rubble.

After the dry components are mixed, water is added to the drum. The total solution preparation time depends on the type of equipment. For devices of forced action, it is usually 2-3 minutes, and for gravity equipment - 5-6 minutes. Reduce or increase the time of the procedure can not be. In the first case, the mixture will turn out to be inhomogeneous, and in the second - too dry.

If there are no concrete mixers in the farm, it is allowed to make mortar for the blind area and manually. In this case, the easiest way is to use the trough and the hoe. When hand-made, all the dry ingredients are thoroughly mixed together. Then the required amount of water is added to the trough. With manual kneading, the solution is not as uniform and qualitative as when using a concrete mixer. Therefore, in this case cement should be taken more.

This is how the concrete is prepared for the blind area. The proportions of the components for the solution must be observed exactly. In this case, the mixture will turn out to be plastic, quality, and it will be easy to work with it. The very same blind area, made with its use, will come out solid, neat and durable.