Quite often when building a house, the following question arises: is it possible to fill the foundation in parts? And how to fill it correctly?
“Cold or hot” seam?
Formwork for the foundation
It is almost impossible to manually pour the foundation yourself at one time, especially if the foundation is large enough. But what to do in this case? There may be two options.
The first is as follows. First, continuous pouring is carried out, after which a break is made at night (for about twelve hours). In this case, a horizontal layer is poured over the surface of the formwork, after which the concrete is covered with film or roofing felt.
The layer under the coating will not have time to harden overnight, and in the morning the so-called milk of concrete will be washed off from the surface. If it comes out, then the filling continues. This method is called “hot joint”, since the layers of concrete do not have time to dry.
The second method is “cold seam” installation. In this case, the filling is interrupted for more than a day. In this case, it is necessary to pour concrete only when the previous layer has completely dried and hardened. It is impossible to pour the foundation on a barely hardened layer. This is due to the fact that during a break, the bottom layer begins to crust over.
When fresh soft concrete begins to fill the previous layer, the crust begins to break at this point, unable to withstand the pressure. As a result, a layer with a crumbling and brittle area appears at the seam site. And this affects the quality of the foundation, because it is the foundation of the house and must withstand significant loads.
We divide the foundation into sections
In order to answer the question of whether it is possible to fill the foundation in parts, you first need to decide how exactly and into what parts the foundation itself can be divided. There is no clear answer here. You can divide the foundation in several ways:
- Horizontally. When the filling is approximately half the height;
- Vertical. In this case, with the help of vertical partitions, the entire foundation is divided into separate sections, which are poured gradually;
- Diagonally. In this case, the partitions are installed at an angle of forty-five degrees.
From formwork to pouring
So, is it possible to fill the foundation in parts and how exactly to do it? We follow the following stages of work:
- We make formwork;
- We choose the pouring option: “hot” or “cold joint”, depending on the period over which the foundation is planned to be poured;
- Prepare materials for the mixture (sand, cement, crushed stone) and a concrete mixer for mixing. It is also necessary to consider how long the chute is needed to supply concrete;
- We divide the foundation into zones for pouring:
- Horizontal (then the concrete will be laid in separate layers);
- Vertical (using vertical partitions, the formwork is divided into parts that will be poured from the bottom to the top of the foundation);
- Diagonal (in this case, the partitions are not installed vertically, but at an angle of forty-five degrees).
The concrete mixture for pouring the foundation is carried out continuously, while one part of the mixture is mixed, the second is gradually poured onto the selected area. The poured mixture must be evenly distributed over the entire surface of the layer.
After pouring, we begin to compact the concrete using an internal vibrator or manually with reinforcing bars. The depth of the layer using the manual method should be about twenty to thirty centimeters;
It is necessary to pour the foundation without haste, carefully and thoroughly. After this, it must be covered with plastic film and roofing felt for preservation and protection from precipitation.
Stages of pouring the foundation
So, let's start pouring the foundation. To begin with, we determine the correct division of the entire site into separate parts. Then we prepare the concrete solution using a mixer. If the volume of work is large enough, a hand mixer will not work here; you can rent a large one.
After preparation, we begin pouring. Along a trench about twenty to fifty meters long, we begin to slowly and gradually feed the mixture into the formwork. At the same time, you should not pour the foundation in only one place, since then it will be very inconvenient to rake it and distribute it evenly over the selected area.
Also, the concrete may delaminate, i.e. its more liquid part will accumulate in the corners and distant areas, and the thicker rocky part will settle in the place where the pouring itself takes place. To prevent this from happening, you need to move the mixer to different places around the foundation.
If this is impossible or inconvenient for various reasons, the concrete supply chute can be extended using simple boards and plastic film or a piece of linoleum lined at the bottom of this makeshift chute.
You can also order a large concrete pump, which will arrive at the site with already prepared concrete. The length of its gutter is sufficient to reach any corner of the foundation. However, this method justifies itself when building a very large house; for a small country house it is not advisable.
Pouring a columnar foundation
When pouring, you can also use a household concrete mixer, which is slightly larger than a manual one. In such a device, the concrete mixture is mixed quickly and efficiently, which fully meets the requirements of pouring. One batch in such a concrete mixer can produce from fifty to two hundred liters of solution, which is enough for the foundation of a country house.
With the latter method, however, the work may take a long time. One cube of concrete may require about 20 mixing cycles (for a fifty-liter concrete mixer). One cycle takes approximately three to five minutes of mixing and ten to supply sand, cement, crushed stone, and then transport the concrete to the foundation.
With this option, filling may take two days. Then the “hot seam” option is used here. After complete filling, we carry out compaction.
It is necessary to fill the foundation in parts correctly, following a few simple recommendations.
- When pouring horizontally, you cannot make a seam where the reinforcement frame passes through. In this case, it is necessary to fill either below or above this joint;
- The fill layers should not be very thin. If there is not enough time, then it is better to carry out vertical filling in small portions. In this case, the vertical seam will be stronger than many thin horizontal ones;
- Concrete must be compacted when pouring to remove air bubbles. Two methods can be used:
- Professional, which involves using a deep vibrator, lowered into concrete for a couple of minutes. When it works, bubbles constantly appear on the surface. It is necessary to ensure that the vibrator does not touch either the reinforcement belt of the foundation or the formwork. The range is fifty to seventy centimeters. The device is gradually transferred to a new area;
- Amateur way. With this method, concrete is compacted by bayoneting. After pouring a shallow layer of twenty to thirty centimeters, a metal rod is used to consistently pierce the concrete in increments of one to two centimeters. You can also additionally hit the formwork itself with a sledgehammer.
- After all pouring and compaction, the concrete must be covered with a film from the sun's rays. You can water the surface of the concrete several times a day, then it will dry evenly (the inner layers dry more slowly). The first days the concrete is watered up to four times, from the third to the seventh days - only three times a day.
The foundation must dry for at least twenty-eight days, only after which you can begin building the house.
The construction of monolithic foundations involves pouring large volumes of concrete mortar. For large construction organizations this does not cause any difficulties; the work is carried out using special equipment. But such machines are not always available to a private developer, and a concrete mixer allows you to supply the solution in portions. Therefore, the question becomes relevant whether it is possible to fill the foundation in parts.
Methods for laying concrete mortar
It is useful for any craftsman, especially a beginner, to know that concreting involves the use of two methods: the hot seam method and the cold seam method.
The first method involves continuous pouring of concrete mortar, that is, the next portion is supplied until the previous layer sets. This method makes it possible to interrupt the process for 12 hours, but during this time the surface of the concrete must be covered with polyethylene or roofing felt. Before starting work after such a period, it is necessary to remove concrete milk from the surface.
The cold joint method involves pouring concrete mortar over long periods of time, during which the previous layer almost completely hardens.
To understand the essence of each method, you need to understand the process of hardening the concrete mixture.
How does concrete harden?
The concrete mass consists of cement, sand, expanded clay or water. The solution acquires fluidity, frost resistance and other special properties thanks to various additives and plasticizers. During the mixing process, the solution does not change its properties, but after preparation, the concrete mass is sent to the mold, where irreversible processes begin.
Setting of the solution
At this stage, the interaction of cement and water begins, which leads to the initial hardening of concrete. But in this state, concrete does not have much strength, so even minor loads can cause irreversible destruction of the mortar.
The duration of this phase ranges from 3 to 24 hours depending on the ambient temperature. The setting time of the solution increases with decreasing temperature. At the initial stage, which lasts about 2 hours at +20 0 C and about 8 hours at 0 degrees, no changes in the structure are noted, so adding a new portion does not affect the destruction of cement bonds.
You can extend the liquid stage of the cement mortar by constant stirring, but it should be remembered that in this case the quality characteristics of the concrete are reduced.
Hardening of the concrete mass
In this phase, hydration of the components of the concrete solution occurs. The process is very slow, so the strength gain lasts for many years. In order for concrete to gain strength in accordance with its brand, it must be kept for about a month. Moreover, the first day of this period is characterized by fairly rapid hardening, then the rate of this process decreases significantly.
During the first hours, the concrete does not have time to harden well, so a new portion of the solution, supplied under high pressure, can cause the formation of microcracks. After three days, the top layers gain sufficient strength and are therefore able to withstand the load of a new portion of concrete.
By analyzing the characteristics of concrete maturation, we can give a positive answer to the question of whether it is possible to fill the foundation in parts. But the following rules must be observed:
- Between serving portions during summer filling there should not be more than 2 hours, in the spring-autumn period - more than 4 hours. Neglecting this rule leads to the formation of seams and a decrease in the strength of concrete.
- If there is a need for a long break in pouring, then this time should be at least 2-3 days. Continuation of work should begin with cleaning the surface with a wire brush, removing dust and water from the concrete. Only in this case can good adhesion of the seams be achieved.
Methods for pouring a strip foundation in parts
To get a strong and reliable foundation, it is necessary to follow the technology of pouring concrete mortar in parts. At the same time, the private developer immediately has the question of how these parts should be arranged: in layers, blocks or obliquely. According to sanitary standards, portions of concrete can be arranged as follows:
- The horizontal method involves pouring concrete mortar layer by layer. To do this, divide the trench into even horizontal parts and fill each part separately.
- When pouring vertically, it is necessary to divide the trench into blocks using metal partitions.
- The diagonal option involves dividing the area at an angle of 45 degrees and installing a complex reinforcing frame. This method is used to create complex shapes, and therefore requires special skills.
Regardless of the chosen pouring scheme, before starting work, a diagram must be drawn up, which indicates the procedure for filling the formwork structure with concrete mortar.
For strip foundations, in most cases, horizontal or vertical filling is used, each with its own characteristics.
- Firstly, they must be laid correctly in relation to the working seam. Horizontal pouring requires the presence of vertical reinforcing elements; block laying should not be carried out without longitudinal reinforcing rods.
- Secondly, vertical pouring requires additional labor, with the help of which strong metal partitions are installed and dismantled during the work process. The horizontal method of filling the formwork structure does not involve any complex manipulations, therefore it is considered simpler and more accessible.
In addition, you should remember some rules for pouring the foundation in parts:
- Neither with the horizontal nor with the vertical method should construction joints be allowed to be located at the same level as the reinforcement bars.
- Each part of the poured solution should be thoroughly compacted to remove air bubbles.
- If the formwork is created only for the above-ground part of the foundation, then when pouring horizontally, one of the seams should be at the level of the ground surface.
The strength and reliability of the foundation of a house largely depends on the correct pouring of the concrete mixture and. Therefore, it is very important to follow all recommendations regarding the technology of work of this type.
When performing construction work of any volume, the foundation is an integral part of any structure. The reliability and strength of the future home depends on it. There are several types of bases for a building, and there are differences in design. Many people are also interested in whether it is possible to fill the foundation in parts.
Types and arrangement of foundations for private construction
There are several types of structures for the construction of private houses and other low-rise buildings:
- ribbon design;
- slab;
- columnar;
- pile
Basic belt type design
For this scheme, at the beginning of the work it is necessary to set up the formwork with a special reinforcing belt, and then pour in the solution. These are all the main parts of the foundation.
About filling in layers
On large construction sites, it is customary to pour concrete immediately in the required quantities. But what should frequency homeowners builders do? Of course, you can get by with a concrete mixer, but there is a problem with limited volumes of the mixture. How to fill a strip foundation in parts? How will this ultimately affect the characteristics of the structure?
In the case of a monolithic base, the seam can be located both vertically and horizontally. In order to get a solid foundation as a result, you need to take care in advance that the components of the foundation are completed according to all the rules. Thus, it is desirable that the reinforcement be done as efficiently as possible, and that its direction be perpendicular to the joint of the monolithic block.
If the seams are in a vertical plane, then the reinforcing parts located longitudinally will reliably connect the corners. If it is assumed that the work will be done in parts, then it is imperative to install vertical reinforcement.
But in fact, on most construction projects the strip base is poured in layers. This is because the vertical pouring technology requires the installation of additional formwork.
If you need to make a strip foundation in parts, then you should definitely know one important nuance. If the formwork is only above the ground, and the underground structure will be poured into a prepared trench, then it is advisable to make the joints at the soil level.
Before the basement part of the foundation is built, you need to wait for the mixture to harden on the first layer. This often takes about two days.
About the setting time of concrete mixtures
Setting is the first thing that happens after pouring. It can be characterized as a gradual combination of the components of the poured solution. If the integrity is compromised during these processes, the concrete mixture will lose its structure.
How long does it take for minimum setting? For most concretes this is about 3 hours. The period depends on the air temperature. Under the worst conditions, this time can last for a day. This is true for the winter season. The warmer it is, the faster the mixture will harden. But this is only the beginning of the hardening process. The structure will still be liquid.
If the lower part of the foundation has frozen for 8 hours, then you can pour in another layer and it will be safe.
Hardening process
These processes can last for a month. But you can proceed to construction work only after the mass has completely hardened. When the solution begins to harden, another layer is poured only after three days have passed.
So. From all this it follows that if the foundation is poured in parts in winter, then the next layer can be added no earlier than after 8 hours. In summer - every 4 hours. If another layer is expected after maximum hardening, then the previous one needs to be thoroughly dried.
How to fill
The first layer is poured as evenly as possible. It is imperative that it be filled with one thread. If you fill from different angles, then you will not be able to achieve uniformity - the result is a crooked base element.
Now you should compact the resulting material using a vibrating tool and level it. After maintaining the hardening interval, you can proceed to the next stage.
Pouring the tape base in several steps is not only convenient and economical, but also reliable, durable and of high quality.
Foundations on piles
Where soils were flooded, people built houses on so-called pile buildings. These are some of the most time consuming ways to create a foundation. Today, this scheme is used for construction on soft soils.
Disadvantages and advantages
Although this scheme seems overly complicated, it has many advantages:
- high speed of construction, as well as time savings;
- minimum amount of ground work;
- you can work whenever you want;
- minimizing the cost of the building.
There are also pile foundations with a so-called grillage. This is a special technology designed to increase reliability. The design of the upper part of the pile foundation is carried out using one of two technologies. A distinction is made between a pile-strip base and a pile-slab structure.
It is possible to make grillages from various reinforced concrete products or to pour a monolithic mass from mixtures. The first method is available for industrial facilities, and the second is an excellent choice for private builders and a way to construct a building with your own hands.
The disadvantage is the complex design of the base. So, the space between the soil and the grillage must be filled.
Construction based on piles and grillages
This is one of the types of pile-and-tape buildings. The tape here will be slightly higher than the soil surface. Construction includes drilling wells for piles.
To make such a foundation, it is advisable to use special heavy concrete with quartz sand. The supporting part of the foundation can be made in several layers. Then, after three days, you can proceed to the installation of the grillage.
This step includes several main steps:
- installation of formwork on piles;
- installation of fittings;
- filling.
The height of this part should be approximately 300 mm. The width is slightly greater than the thickness of the walls. The upper part of the foundation can be made in parts, in several layers.
Technology for the construction of basic types of foundations
From afar, for people far from construction, the process of pouring concrete looks the same for the main types of bases for buildings. It seems that the concrete is simply fed through a special sleeve and completely fills the cavities. But everywhere there are certain nuances. And building a foundation in parts also has its own peculiarities.
For example, it is much easier to design piles than to create a base for a structure based on tape. With the belt method, the process of pouring into several layers will be the optimal solution, and then after a certain technological period you can move on to another layer. In the case of piles, the concrete mixture is fed into the hole for each pile.
In the case when a slab part of the foundation is being built, then in this case it is prohibited to use such technology. The material is dumped into a pile, and then it is simply leveled. But this operation must be carried out as quickly as possible - within 30 minutes.
Repair work
Sometimes there comes a time when the basic level requires renovation. It is much easier and cheaper to make a new base part. Replacing the foundation in parts will cost significantly more than a complete replacement. But you can try pouring the mixture into several layers.
In general, the entire repair consists of digging a trench around the perimeter and cleaning out cracks. Then you should use anchors to strengthen the reinforcement and proceed to pouring a new solution. This will strengthen the current base and stop cracking.
When the work of pouring the first layer is completed, it is necessary to cover it so that the hardening and hardening processes take place more efficiently. This will also protect the flooded area from rain. There must be air gaps at the edge.
Before pouring the foundation in parts, it would be a good idea to prepare a sketch of the future foundation on a piece of paper. You need to indicate on this sheet the time when you completed the first layer. This makes it easier to keep track of time intervals and easier to avoid mistakes with subsequent layers.
When building a house, in any case, the question arises: is it possible to fill the foundations in parts and will such pouring affect the quality of the foundation? This question arises among people on the basis that the main pouring of the foundation all at once requires not only great effort, but also the presence of special equipment and machines. We are not talking about cranes or excavators. The thing is that there is simply nowhere to mix a large amount of concrete for pouring. Yes, and everything needs to be poured very quickly, since concrete tends to harden gradually.
Pouring concrete in parts does not reduce the quality of the foundation.
Today, there is a technology for pouring the foundation in parts, which does not reduce its quality.
Therefore, the answer here is clear: you can fill the foundation in parts. This is especially suitable for strip foundations, where the largest amount of pouring solution is spent.
Taking into account time intervals when pouring in parts 
Foundation pouring diagram.
Before we consider in detail one of the methods of pouring parts of the foundation, it is advisable to understand several important points. They relate to the time and intervals of hardening of concrete mixtures. This is extremely important, since incorrect timing can reduce the quality of the foundation.
An important issue is the hardening stages of the concrete mixture. There are two such stages in total. This is setting and hardening. Both processes have their own characteristics and their own time intervals.
These characteristics differ for different mortars and brands of concrete. However, concrete for pouring into a strip foundation all has the same parameters and features.
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Intervals during setting
Scheme of the macrostructure of concrete.
Setting is the very first process in the solution, which occurs immediately after pouring the formwork. It is characterized by the gradual binding of individual components of the solution to each other. The setting time is theoretically a little dangerous, since if the concrete is touched during this time, its structure in this place can deteriorate, as a result of which the setting will be weak or not set properly at all.
The minimum setting time is 3 hours. This is typical if the ambient air temperature is above 15°C. The maximum time is one day. This is more true when it’s frosty outside. Therefore, the higher the temperature, the faster the solution will set. This process is characterized only by the beginning of solidification. At the same time, the structure remains liquid. When pouring in parts over a period of up to 8 hours, you can pour a new, not too thick layer of concrete on top, and this will not cause any defects. If you do this right away, when one day has passed, the base may deteriorate considerably.
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Accounting for curing time
Concrete mix composition table.
The second stage is called hardening. It lasts for a whole month. Only at the end of this period will the concrete be fully hardened and ready for any load. Such a long period is explained by the fact that a fairly thick layer of mortar is poured into the foundation, which takes a long time to completely harden.
When the hardening period begins, the next part of concrete can be poured only after three days. This cannot be done for a day to three days, as numerous significant cracks may appear in the concrete. Moreover, you may not even see them, since they will be located in the thickness of the layers. But they will make themselves known very soon after the construction of the house is completed.
Based on the above, there are two main things to remember. Firstly, pouring the second layer can be done no more than 8 hours later in winter, no more than 4 hours later in spring or autumn, and no more than 3 hours later in summer. If you are going to pour the next layer after the previous solution has completely hardened, then the base will need to be prepared: dry and clean with a metal brush. And only then can you start filling again.
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Tips for grouting methods that take into account seams
Calculation of concrete mixture.
In addition to the time intervals, proponents of pouring a foundation have another important question. It concerns specific pouring methods. There are two of these methods: block and layer-by-layer pouring of concrete. In this regard, it is recommended to adhere to the following rules:
- If the foundation is strip and the trench is poured underground, the formwork should be poured strictly along the ground. In this case, the formwork is poured exactly end-to-end, that is, it will be a layer-by-layer pour.
- If your foundation is strip monolithic, then it is recommended to do block filling. That is, the seams should be located perpendicular to the joints of the monolith blocks. An option with layer-by-layer filling is also possible here, but in this case it is necessary to provide for the presence of strong vertical reinforcement.
Considering all these tips, you can start pouring the foundation in parts. This process is carried out in most cases in the same way as regular pouring. But you just need to fulfill the main requirements regarding the filling method and time intervals.
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Overview of methods and sketching
Foundation construction.
Before you start pouring, draw up a small three-dimensional diagram of the foundation for yourself. The diagram involves designating places that will be divided into parts for pouring concrete. There are three main ways of division.
The first method is a vertical section. In this case, the base of the foundation must be divided into the required number of separate parts, which are separated from each other by partitions made of strong metal. After hardening, the partitions are removed and pouring continues. If such filling is expected, mark these parts immediately on the sketch.
The second method is oblique filling. This is the most complex method of filling, which is completely impractical and unprofitable to use for small residential buildings. It is used for complex structures and is produced in most cases by experienced professionals. The bottom line is that the territory is divided into parts by diagonals, between which there must be angles of a certain size (usually 45 degrees).
The third method is the horizontal type of pouring the foundation in parts. In this case, the depth of the entire foundation is conditionally divided into several parts (layers). There is no need to place partitions between the parts if you do not use the vertical pouring method. You can simply determine the height of the layers for yourself and put everything on the sketch. And then fill in according to the sketch.
It is advisable to even indicate on the sketch the specific dimensions and depth of the parts to be filled with mortar. And after each individual fill, cross out the treated areas on the sketch, and also mark the end time of the fill. This will make it much easier for you to navigate the process.
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Characteristics of the pouring process in parts
Scheme of lattice foundation formwork.
After drawing up a basic diagram, proceed directly to constructing the foundation - pouring it. First make the formwork and install it around the area you will be pouring first. After this, mix the concrete solution. Make sure it doesn't turn out too watery. Otherwise, you will have to wait a long time for it to harden, even in warm weather.
Now is the most crucial moment. The freshly prepared solution should be poured evenly onto the fenced area. Moreover, this must be done in one thread. The fact is that if you pour at different angles, the required uniformity will not be achieved, and the foundation may end up crooked.
Next, you need to level and compact the poured part of your foundation. This is done using a special tool that creates vibration. If you don't have one, use a flat piece of wood. Naturally, the effect will be slightly worse.
Now you need to maintain a certain interval before starting to fill the next layer (using the horizontal method). It is recommended to cover the flooded area with protective material if there is a threat of rain, snow or strong sun in the next three days.
In this case, be sure to leave gaps at the edges and make sure that the material does not touch the solution. In good weather, shelter can be neglected.
As you can see, you can fill the strip foundation in parts. And in some cases this is even necessary, as it allows you not only to save your money, but also to make the foundation better and more durable. Therefore, do not be afraid, read useful tips and try - then you will definitely succeed!
When a monolithic foundation is poured, there is a need for large volumes of concrete, which sometimes exceed several cubic meters. Construction companies approach this issue by using heavy equipment such as concrete pumps and mixers. They allow you to mix the solution and feed it into the formwork.
Private developers do not always have the opportunity to use such equipment, because it is quite expensive, and for small areas such an approach may be unacceptable due to the lack of access roads for equipment. This problem can be partially solved using a concrete mixer, but the volume of mixture that can be prepared in one load is limited. In this case, builders are wondering whether it is possible to fill the foundation in parts, because this sometimes affects the strength of the foundation and its operational properties.
Maturing of concrete
Concrete is a mixture of fillers and cement that are mixed with water. To increase fluidity, give the mixture special properties and increase frost resistance, plasticizers and additives can be added to concrete during mixing. At this stage, you may also be wondering whether it is possible to fill the foundation in parts. Pouring a liquid solution into a form called formwork involves the beginning of irreversible processes in concrete, namely:
- grasping;
- hardening.
During the first stage, the solution begins to come into a solid state, because water and cement components interact with each other. But the bonds between the ingredients remain not strong enough, and if a load is applied to the material, it may collapse, and the solution will not re-set.
What else you need to know about the stages
This phase can vary depending on the air temperature and lasts from 3 hours to a day. As the temperature decreases, concrete takes longer to set. At the initial stage, it remains liquid, without changes. If during this period a new portion of concrete is added to the formwork, then destruction of the cement bonds will not occur.
At a temperature of 20 °C, the liquid stage will last for 2 hours, but if the temperature drops to zero, then this period will last for 8 hours. The time before setting begins can be extended by constantly mixing the concrete, but its characteristics will be improved, so you should not abuse the method.
Pouring concrete at the hardening stage
If you are faced with the question of whether it is possible to fill the foundation in parts, you should also study the stage of concrete hardening. This phase will last quite a long time, because the components will gain strength over many years. The first 28 days are considered a mandatory period for the structure to remain in place until it gains strength. In this case, hardening occurs quickly, which is especially important for the first day; after that the speed slows down.
In the first hours after setting, the concrete will not have such a high hardness, and if you add another portion, this may cause small cracks to appear, because the load on the structure will increase. After three days, these loads do not have a similar effect on the first layers. Taking into account the peculiarities of the maturation of the solution, it can be argued that pouring the foundation in parts can be carried out, however, it is important to follow certain rules.
When a private developer wonders whether it is possible to fill the foundation in parts, first he must study certain rules for carrying out such work. They state that when mixing individual batches of concrete in succession, you should limit yourself to two hours or less between pours in warm weather. If work is carried out in the off-season, then this time can be increased to 4 hours. The strength of the foundation does not change, and seams are not formed.
If you are wondering whether it is possible to fill the foundation in parts, then you must remember that long breaks in work should not exceed three days. After the break, the base of the foundation, where a fresh portion is supposed to be poured, should be cleaned of moisture, dust and dirt. It is important to clean with a wire brush. In this case, the seam will have good adhesion.
Step-by-step instructions for pouring the foundation in parts
It is better to pour the foundation continuously; sometimes work is not stopped for this even at night. As a result, it is possible to obtain a monolithic structure that has a high load-bearing capacity. But continuous pouring can be achieved only if you use a purchased solution, which will be supplied to the formwork from the concrete mixer tank. If the solution is prepared directly at the construction site, then instead of this technology, the partial pouring technique is used.
When asking the question of whether it is possible to fill a strip foundation in parts, you should know that if certain conditions are met, such a structure will not be inferior in terms of strength to the one formed using the monolithic pouring method. The technology of intermittent casting is as follows: at the first stage, it is necessary to form a reinforcement frame, which will consist of horizontal rods. They need to be separated by vertical connections. The distance between the horizontal rods should be selected according to the volume of fill. Usually it ranges from 10 to 12 cm.
If you are thinking about the question of whether it is possible to fill the foundation in parts, you should read useful tips. From them you can find out that at the next stage you can prepare a solution to pour the first layer of concrete. In this case, the formwork should be filled evenly, while the thickness of the first layer should be equal to the distance between the horizontal rods, which should be reduced by 1.5 cm. This answers the question of how the foundation can be filled in parts with reinforcement. The second layer will flow under the horizontal reinforcement. As soon as the filling of the first layer has been completed, you can begin to prepare the second portion of the solution, which is poured from above.
This technique should be followed until the desired base height is achieved. The technology is also called layer-by-layer, and the individual layers will be fastened together with reinforcement. However, if the first layer has already begun to set and has reached the hardening stage, then the second pour can begin only after the first layer has hardened.
Many novice home craftsmen wonder whether it is possible to fill the foundation in parts; the instructions presented in the article will help you understand this. From it you can learn that after pouring the first layer, when it is not intended to immediately begin forming the second, the surface should be wrapped in polyethylene, which will prevent unwanted evaporation of water. In this case, the second layer can be formed the next day; first, concrete milk must be removed from the surface.
If you have not had experience pouring a foundation before, then you first need to think about what brand of concrete you will use. It is recommended to pay attention to the operating conditions of the future design. This is due to the fact that different brands are characterized by a certain moisture resistance and frost resistance. If you are faced with the question of whether it is possible to fill the foundation in parts, and what kind of concrete to carry out this work, you must definitely decide.
For difficult conditions, varieties M-300 and M-450 are usually used. If the conditions are not so severe, then concrete grades M-100 and M-200 can be used. M-100 and M-450 are prepared from the same ingredients, but the recipes are different. For example, M-100 is mixed from:
- 4 parts sand;
- 1 part cement;
- 6 parts gravel.
Whereas to prepare M-450 you should use:
- one part sand;
- one part cement;
- two parts gravel.
Conclusion
In order for cement stone to form, the solution will require 1 part water to 4 parts cement. But when you study the ratio of cement and water, you will understand that most often the proportions look like this: 3 to 2 and 2 to 1.
When pouring a monolithic foundation for a house, the required volumes of concrete often exceed several cubic meters. Large construction companies solve this problem with the help of heavy special equipment - a mixer and a concrete pump, with their help the solution is mixed and fed into the formwork. However, private developers cannot always afford such equipment, and in small areas there may be no access roads for heavy equipment. A concrete mixer will help partially solve the problem, but the volume of solution prepared in one load is limited. Builders then have a question: is it possible to fill the foundation in parts? Will this affect the performance properties and strength of the foundation?
Is it possible to fill the foundation in parts?
Stages of concrete maturation
Concrete is a mixture of cement and fillers - sand, gravel, expanded clay - with water. To improve the fluidity of the solution, increase frost resistance and give it special properties during mixing, various additives and plasticizers are also added to the concrete.
After preparation, the liquid solution is poured into a form called formwork, after which irreversible processes begin in the concrete:
- Setting of concrete. During this stage, the liquid concrete solution turns into a solid state due to the interaction of the components of cement and water. However, the bonds between the components are still very fragile, and under the influence of a load they can break, but the solution does not re-set.
This phase lasts, depending on the air temperature, from 3 hours to 1 day. The lower the temperature, the longer it takes for the concrete to set. At the same time, in the initial stage of setting it remains liquid without any changes in structure. If during this period of time a new portion of concrete is added to the formwork. No destruction of cement bonds will occur. At a temperature of 20°C, the “liquid” stage lasts approximately 2 hours; at zero temperature it lasts approximately 6-8 hours.
You can extend the time before setting begins by constantly stirring the concrete, but this will worsen its characteristics, so you should not abuse this method.
- Hardening of concrete. This phase lasts for quite a long time; due to the gradual hydration of the concrete components, the foundation gains strength over many years. The first 28 days is the mandatory period of curing of concrete until it gains strength corresponding to its grade. Hardening occurs quite quickly in the first day, then its speed slows down.
- In the first hours after setting, the hardness of concrete is still low, and adding the next portion of concrete can lead to microcracks due to increased load. After three days of hardening, as a rule, these loads do not have such an effect on the first layers of concrete.
Based on the characteristics of concrete maturation, we can say: it is possible to fill the foundation in parts. In this case, you need to follow some rules:
- When mixing batches of concrete sequentially, the time between pouring them into the formwork should not exceed 2 hours in warm weather and 4 hours in the off-season. In this case, no seams are formed, the strength of the foundation does not change.
- If you need to take a long break from work, it should be at least 2-3 days. After the break, the surface of the foundation on which a fresh portion of concrete will be poured must be cleaned of dust, moisture, and also cleaned with a wire brush. The seam will have good adhesion.
- When pouring the foundation in parts, it is necessary to follow all recommendations for reinforcement.
Methods for reinforcing corners at the foundation
Layers or blocks? (fill in parts)
Another question that worries developers is how to properly distribute portions of concrete? Three types of seam placement are possible:
- Horizontally;
- Vertical;
- At an angle.
SNiP gives specific instructions in this regard: the seam between sections of a monolithic foundation should be directed perpendicular to the axis. That is, for columns and piles only layer-by-layer pouring of concrete with the formation of horizontal joints is suitable.
For a strip monolithic foundation, the seams can be located both vertically and horizontally. To maintain the strength of the foundation, high-quality reinforcement is necessary, directed perpendicular to the joints of monolithic blocks. If the seams are made vertically, then the longitudinal reinforcement must firmly connect the corners of the building. When layer-by-layer horizontal pouring, the installation of vertical reinforcement is mandatory. In practice, strip foundations are usually poured in layers, since pouring individual vertical blocks requires the installation of additional formwork.
The process of pouring the foundation in parts
When pouring a strip foundation in layers, it is necessary to take into account one feature: if the formwork is erected only in the above-ground part of the foundation, and the underground part is poured into a dug trench, then the joints of the rows are made at the ground level. Before pouring the base, it is necessary to wait for the concrete to harden in the underground part for several days, otherwise the mass of concrete poured into the formwork may, with its weight, destroy insufficiently hardened cement-hydrated bonds. Microcracks will appear in the concrete, it will become more hygroscopic and will begin to collapse over time.
Pouring strip foundation
When pouring a slab foundation, the seams are placed either horizontally or vertically in a direction perpendicular to the short side of the slab. This arrangement of seams will reduce the likelihood of fracture under non-uniform loads and heaving of the soil.
Technology for pouring a monotonous foundation
Plasticizers
The addition of additives and plasticizers can improve the fluidity of concrete, so that vibration of the concrete can be eliminated from the pouring process. This will reduce the impact of a new portion of solution on already filled layers.
The solution is mixed after preliminary calculation. When adding plasticizers, you must strictly follow the manufacturer's recommendations regarding dosage, since failure to comply with the proportions can lead to the opposite result.
Concrete mixing process
Video - main mistakes when pouring a foundation
The question of pouring the foundation in layers or in parts quite often arises among private developers. They do not have the capabilities of large construction companies that have their own mixers that deliver concrete mixture to the construction site on schedule, and concrete pumps that supply the solution to any point on the formwork. The owner of a land plot who decides to independently construct the underground part of the structure may only have a small-volume concrete mixer, which can only partially satisfy the needs for the required amount of solution, since its resources are limited. But is it possible to fill the foundation in parts, in several stages, if some time passes between mixing cycles? This is worth looking into.
Stages of concrete maturation
After installing the formwork and installing the reinforcement, the foundation is poured with concrete mortar. It is mixed in a certain proportion from the required grade of cement using fillers in the form of sand, gravel or crushed stone, possibly expanded clay, and, of course, water. The properties of concrete are improved by plasticizers and various additives that increase frost resistance and other necessary characteristics, depending on the required conditions.
After concrete has been poured into the foundation formwork, either completely or in parts, irreversible processes begin to occur in the solution, consisting of two main stages:
- grasping;
- hardening.
The first phase lasts several hours - from 3 to 24. The time directly depends on the air temperature - the fewer degrees the thermometer shows, the longer the concrete mixture will set. The setting process, in turn, has a so-called “liquid” stage, during which the internal structure of the material undergoes virtually no changes. At a temperature of 20 degrees, for example, the “liquid” period lasts about two hours, and at a temperature close to zero degrees, the initial stage of setting can last up to eight hours. This statistics applies to both strip and slab foundations.
It is during the “liquid” setting phase that it is possible to fill the foundation in parts without fear of breaking the cement bonds. As a result of hardening, such concrete turns into monolithic stone.
It is not recommended to prolong the time for complete setting of the concrete solution by constantly stirring it. Firstly, this can significantly worsen the characteristics of the future foundation. Secondly, there will be a possibility that the reinforcement or embedded parts will shift from the design position, even if the elements are installed quite rigidly. Thirdly, uneven mixing will lead to different stages of setting of the concrete solution, which will sharply reduce the service life of the object.
When asked whether it is possible to pour the foundation at least in parts immediately after the mortar has finished setting, experts answer that in no case is it possible. The fact is that during this period the concrete is still too weak, and the load from the next portion of the mixture will certainly lead to the appearance of microcracks in its thickness. Layer-by-layer pouring “with a break” is permitted only after three days of hardening of the concrete mass. Further, the loads on the lower layers of concrete will no longer have such a fatal effect.
The concrete hardening stage takes a long time. It gains its final strength after a few years. But there is no need to wait for such a long time, so further work on the construction of the above-ground part can be carried out after the mandatory holding period of 28 days. The maximum rate of hardening of the monolith occurs during the first 24 hours, slowing down more and more every day. After a month, the concrete acquires the required strength and characteristics corresponding to its brand.
conclusions
When asked whether it is possible to fill the foundation in parts, experts, based on the characteristic features of the maturation of the concrete mixture, answer positively. But at the same time, they recommend following certain rules:
- To prevent the appearance of delaminations in the thickness of the foundation, sequential filling should be carried out taking into account temperature conditions. In the warm season, a time interval of no more than two hours is allowed between pouring layers of concrete, and in colder periods - no more than four hours. The strength of the monolith, in this case, will not be affected;
- When work is stopped for some time, pouring onto a previously completed concrete layer can be done no earlier than three days later. At the same time, you will need to remove moisture and dust from the concrete surface by first cleaning it with a wire brush. The foundation is usually covered with film during “rest”.
When pouring concrete in parts, it is necessary to observe not only the conditions associated with pauses between laying layers. Important requirements may relate to issues of correct installation of fittings. In this regard, the work should be strictly guided by the instructions of the project documentation.
Options for phased pouring of strip foundations
Building codes provide for three options for phased foundation pouring:
- horizontal – in layers;
- vertical - in blocks;
- diagonal - in parts, at an angle.
The latter method of dividing pouring areas is quite complex and irrational when constructing foundations for small residential buildings. It is used in the case of construction of complex and bulky objects, and is carried out only by professional teams.
For strip foundations, it is advisable to use horizontal and vertical methods of dividing or placing seams.
The strength of the foundation after it is poured in parts and subsequent hardening is ensured by the correct placement of the working reinforcement in relation to the joining seams of the monolith. It should be perpendicular to the joints. For example, when pouring horizontally layer-by-layer, the presence of vertical reinforcement is a prerequisite. And when laying a concrete mixture in blocks, it is necessary not only the presence of longitudinal reinforcement, which is present in any strip foundation, but also its strong adhesion at the corners of the building and at the locations of the interface nodes.
In practice, horizontal pouring is most often used for strip foundations. Its technology is simpler, more accessible and understandable. The option with vertical seams requires the installation of auxiliary formwork and, as a result, additional labor and material costs. Strong metal partitions are installed between the blocks, which are removed during the process of filling the adjacent area with concrete.
When dividing layers horizontally, the question often arises: is it possible to fill a strip foundation with parts of indefinite volume? To which experts respond that the filling level of the formwork and the thickness of the layers should depend on the location of the vertical reinforcement. Situations where the horizontal joints of the foundation and the reinforcing bars are at the same level are not acceptable!
Another nuance that should be taken into account when installing a strip foundation in parts. If the underground part of the structure is poured simply into a trench, and the formwork is installed only for the base, then one of the horizontal joints must be made at the ground level. After this, the monolith is left to harden for several days, otherwise, under the weight of the mortar laid in the formwork, the cement bonds of the underlying concrete layer may be destroyed.
Is it possible to fill the foundation in parts?
Private developers do not always have the financial and organizational ability to pour the foundation in one go. This is due to the impossibility of uninterrupted delivery of concrete mortar to the construction site, the lack of capacious concrete mixers, and efficient pumps for preparing and supplying the mortar to any formwork area. In addition, there are not always convenient transport routes for the access of heavy special equipment.
As a rule, most owners of private plots who independently construct the underground part of the building have a small concrete mixer. It prepares the concrete mixture in batches and can partially satisfy the needs for concrete. The required volumes of concrete to form a strip foundation, even for a small building, are calculated in tens of cubic meters. This depends on the length of the perimeter of the building’s contour and the depth of the trench. In one day of light, doing manual work on a small electric concrete mixer, it is problematic to obtain the required volume of solution.
When building a house, in any case, the question arises: is it possible to fill the foundations in parts and will such pouring affect the quality of the foundation?
Naturally, most developers have a question: is it possible to fill in several stages? Will this affect the strength characteristics and performance properties of the base? After all, a certain amount of time passes between the stages of preparing and pouring the mixture. Let's take a closer look at the hardening stages.
Concrete: stages of hardening
According to the technology, the foundation is poured with concrete after installing the formwork panels and the reinforcement cage. The solution is mixed according to the recipe.
Special plasticizers and additives affect the characteristics of the mixture, increase the resistance of concrete to negative temperatures, and also improve the fluidity of the composition. The concrete solution vibrates less when feeding subsequent portions, which reduces their negative impact on previously poured layers.
After the formwork begins to be filled with a liquid mixture, the solution irreversibly begins to change its structure under the influence of the ongoing processes. Regardless of whether the solution is poured in one step or in several stages, the changes are irreversible and the processes occurring consist of two main stages:
- Setting of the composition.
- Hardening of concrete.
Today there is a technology for pouring the foundation in parts, which does not reduce its quality
Different brands of concrete solutions differ in their characteristics. However, the correct determination of time intervals during hardening and setting for any type of mixture affects the quality of the foundation. Each phase is characterized by its own characteristics and time parameters, which we will consider further.
Setting Features
The first phase is setting. This process, during which the flowable concrete composition gradually turns into a solid phase, begins immediately after pouring into the formwork or trench. The solution thickens when cement interacts with water and fillers.
At the initial stage, there are weak bonds between the components of the mixture, which can easily be broken under the influence of forces, after which it is impossible for the composition to re-set. The setting period requires special care with concrete, which must not be touched as this may damage the structure.
At the “liquid” stage of the setting process, topping up can be done, since the internal structure of the mixture remains constant. The setting time is determined by the ambient temperature. The duration of the “liquid” phase decreases with increasing street temperature.
The minimum duration of the first phase is 3 hours at an ambient temperature of at least 15 degrees Celsius. The worst setting occurs at subzero temperatures. In this case, the time interval until the end of the first stage is 24 hours.
Before you start pouring, draw up a small three-dimensional diagram of the foundation for yourself.
- Reducing the strength properties of the formed base.
- Shift of embedded elements, reinforcement bars from the coordinates provided for by the project.
- Uneven setting of the mixture due to non-uniform mixing of the composition.
If pouring the foundation in parts takes no more than a shift, then new, not very thick layers of the mixture can be poured during this interval. This will not affect the quality of the base, which after hardening will turn into a monolithic mass. After 24 hours, topping up is strictly not allowed, since simultaneous setting will not occur, and delamination of the massif will cause cracks.
While maintaining a liquid structure at the beginning of the stage, setting gradually moves into the second stage - hardening.