How to pour a foundation in the winter

Traditionally, the construction of the house has always belonged to the "summer" activities among private developers and even very few people thought to begin active work in the winter.However, it so happened that the Russian winter - long enough, and in some regions of the cold season general reaches terms in 6 ÷ 8 months.And if we exclude them from the process of construction of the building, the construction of houses can last for several years.To expedite this process, special technology and made special materials that allow to start concrete work or not to stop them, and the winter cold have been developed.

, however, to the structure of the base turned reliable and monolithic, it is necessary to provide very precise as to fill the foundation in the winter well.Knowing all the nuances of this rather complicated process and following all technology recommendations can start work and at low temperatures so as not to lose the winter time in vain.Often, starting construction in this period, the autumn

owners expect to move into a new house ready.

addition to the need to speed up the construction of the house, the need for filling the basement in the winter and can be caused by specific reasons.For example, they are resorting to such measures, and because of the fact that the soil in the area of ​​increased flowability differ, so working with it is much more convenient when it is - in the frozen state.

When the device of the foundation you need to remember that it is not recommended in winter to establish a columnar structure, as small amounts of concrete at hardening unable to retain some heat, cool rapidly in violation of the processes of hardening solution and maturation.That is why, if the foundation is poured in sub-zero temperatures, you need to choose a monolithic or belt option.

begin work on the device foundation for the construction of the house necessary to preparatory work, which in winter is usually characterized by high labor intensity .

Preparations

• place, where it is planned to erect the building, you need to clear not only from the snow, but also on the soil surface.
• Furthermore, held the overall layout of treated area - this is done with the help of pegs installation, which is pulled by a cord - it visually mark the external dimensions of the future foundation.

next step is markings required trench width - also installing poles and stringing rope.To make it convenient to dig a trench for the foundation, on a tight rope outlines its internal border, and on it hollowed out in the ground with the gun or pneumatic jackhammer flat strip - it and mark the edge of the foundation.

• Further, digs a pit, trench, which should have a depth of at least 500 ÷ 750 mm.Depth is usually calculated according to the type of soil.

If the soil does not lend itself shovel, it is necessary to gradually pulverize his hammer or pickaxe .In this case the earth is removed from the pit layer.

• When the trench will be fully excavated, carried out their preparations for pouring concrete solution.To this end, the bottom of the sand backfill produce - it should be dry, so you need to choose the material that has been stored indoors or at least under a roof.Sand Pillow is an excellent moisture barrier for a strong foundation, if it is well compacted.After compaction layer thickness should be 80 ÷ 100 mm.

on a sandy base is poured a layer of gravel the same thickness and also carefully compacted.

• Further, from the bottom of the trench and the height of the foundation of the future, built from boards shuttering.If equal quality boards used for it, that the assembly fit tightly to each other, the more insulating materials, would like, is not required.

If between boards formed slit is ri ck etc. osachivaniya through them the solution, it is best to install reinforcing structure gidroizolirovat formwork polyethylene film, at least 200 microns thick.

Practical advice - to use such an insulating layer in all cases.It will support the correct water balance in a concrete solution (the water will not leak or be absorbed into the casing material), and the maturation of the concrete will more evenly and efficiently.

encourage you to review the detailed construction of the formwork technology for the foundation with his own hands.This article describes the main tasks of formwork technology and its step erection.

addition we advise to pay attention to the material - about basement waterproofing, asit will keep the integrity of the waterproofing of the foundation for years to come.

Another option formwork waterproofing is to use a conventional inexpensive roofing material.

• can separately noted that "winter" foundations often use permanent formwork of polystyrene foam, which also will be the insulation for the filling of the solution and not allow him to quickly freeze.solidification process will take place gradually, which is very important for the strength of the concrete.

• Next, the prepared formwork mounted design of reinforcing rods, which are connected to each other by welding or wire twists.For this design suitable metal rods with a diameter of 8 to 15 mm - this option will depend on the width of the foundation and planned estimated load him.

After all preparatory processes will be carried out, you can start calculations consistency and component composition of the solution.These parameters are chosen according to the exemplary temperature at which concrete works will be carried out.

Pouring concrete

When at prepara- solution must take into account factors such as the brand of solution, the temperature outside, the quality of the material, special additives, which are able to delay the crystallization of water at low temperatures.Without account all these nuances solution after curing will not be as strong and durable, what is planned as quickly begin to crumble.In this case, the work will have remodel completely because such a foundation is simply not stand the load from the walls.

• To mitigate the impact of low temperatures, after the formwork device, before pouring it in concrete structure erected on a temporary tent .Its frame can be put together from planks and beams - a basis should be firmly established and have a height taller than a man, as a builder have to work under it.You can use a temporary frame and metal parts - profiles and fittings.

Outside construction is delayed reinforced polyethylene film , having sufficient strength to withstand wind load and the severity of the snow.The roof of the tent should have a fairly steep slope to rain on it not been detained, or even reinforced film can tear, and the presence of an awning simply lose meaning.

Fabrics film covering foundation should be firmly bonded to each other, and even better - to buy or rent ready-made awning specialist, who will need to simply install over the design.

Such temporary tent will maintain the desired temperature conditions for the gradual solidification of the solution without the risk of freezing, ie those nt Article Anet kind of greenhouse, which will stop the hot air.When severe frosts at such a shelter you can turn heats the devices, such as a heat gun.

to pouring concrete in the tent need to create a temperature not lower than 5 ° With , concreting without antifreeze additive it iscritical.Lower temperatures lead to destructive processes and crystallization.

But at the critical temperature setting of concrete and hardening will take much longer, so if you have the opportunity to move to a fill foundation warm days, it is recommended to do.By the way, if we analyze the table with concrete ripening times in different temperature conditions, it can be seen that the gain over time in some cases, only a very insignificant.

• When pouring the foundation in the winter time for solution is recommended tsemen t t onkogo grinding that generates more heat when entering the reaction with water and additives thannormal.For mixing concrete is best applied heated to 40 ÷ 80 ° C water.

brand of cement used	Tepreratura water for preparing the mix	concrete temperature at the outlet of the mixer
Portland;slag-portland cement;Portland cement below 600	80	35
Fast setting Portland cement and Portland cement below 500	60	30
aluminous cement	40	25

when mixing the solution on a hot water, it is first mixed with additives, and then introduced into the cement parts and mixed thoroughly . since manufacturing time increase solution helps to maintain a long term solution to the desired temperature.The homogeneous mass of the solution is better fills the entire space of formwork, as its turnover increased.

The thin, well-mixed concrete solution is often added to a medium or small quantities gravel , which will add to him stiffness , it is necessary for the foundation.

Also rubble and concrete frost resistance additives, it is often added plasticizers, they contribute to the strength and moisture resistance of concrete and its adhesion to the reinforcing structure.Due plasticizers can reduce the consumption of cement 25% solution.

• More one way to keep the foundation in a heated state - summing it to him on the electric cable 12 volts .It will heat the reinforcement bars, which in turn otdas reflux eplo solution, not allowing him to smerznutsya .Significant disadvantages of this method are heating the complexity and bulkiness of the preparatory work, the need for special equipment, wasteful use of energy, and hence - and very substantial financial costs.

• can hear many different opinions about the use of special additives in the concrete antifreeze solution, they say, they make it possible to carry out the foundation fill in subzero temperatures without any other measures of temporary construction insulation.So Do this and that from itself represent antifreeze additive in concrete?

This special chemical compounds that solve two main tasks.Firstly, they increase the density of the aqueous base solution and then - dramatically lower its freezing point.Second, they contribute to the peculiar catalysis concrete maturation process by more active involvement in the reaction of atmospheric oxygen molecules is at low or even negative temperatures.

in building practice for the preparation of "winter" solutions typically used nitrite or sodium formate , potash, calcium hydrochloride, lignosulfonate .These reagents can be purchased in specialty stores, but prepare their own high-quality concrete, without special equipment, without special receptions and calculate the correct dosage - is extremely difficult, not to say more categorically.Incorrect ratio of component capable of completely spoil the concrete, which even in the most optimal pour conditions get fragile, crumbly, loose and etc .In addition, it is necessary to bear in mind that the use of special additives may «disastrous" impact on the state of fixtures - not just in metal suitable for this purpose.

Yet another consideration, speaking not in favor of antifreeze additives.Yes, they allow certain processes at low temperatures.However, this does not mean speed up the construction work.Take a look at the table - there are specified time frames set of vintage concrete strength at low temperatures using antifreeze additives:

type antifreeze additive	average temperature during the ripening	1 week	2 weeks	4 weeks	3 months
sodium nitrite	-5 ° C	30%	50%	70%	90%
-10 ° C	20%	35%	55%	70%
-15 ° C	10%	25%	35%	50%
Potash	-5 ° C	50%	65%	85%	100%
-10 ° C	30%	50%	70%	90%
-15° C	25%	40%	60%	80%
-20 ° C	23%	35%	55%	70%
-25 ° C	20%	30%	50%	60%

Conclusion: even with a relatively small frost - order - 5 ° with , andwith antifreeze additives, to talk about the readiness of the foundation to continue any further construction work was possible only after 3 months. So does it make sense in a private building rely on this technology, if at the time of winning almost will not, and solution quality can be significantly reduced?What is beneficial and justified in large-scale industrial construction with its laws of planning and logistics, in a small private building can turn into a completely unjustified, unnecessary waste of energy and resources.