Is it possible to fill the foundation in parts: step-by-step instructions, features and recommendations. Pouring the foundation in parts When you can pour the second layer of concrete
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.
Why layer filling?
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 a break, where you are supposed to pour a fresh portion 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, 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.
The durability of any building depends on the reliability of its foundation. What kind of soil, what height of the building it will support, what kind of foundation to choose for a given building - all these questions are important for the strength of buildings. But often when deciding to build a building, they decide on their own only what type of foundation will be chosen
A strip foundation does not require special equipment for delivery to the site, which is why home craftsmen prefer it.
For buildings in suburban areas, block or strip foundations are most often used. The first ones require special equipment: they must be somehow delivered to the site, somehow lifted for installation on site. Therefore, home craftsmen give preference to strip foundations. So that the source material can be delivered to the site without much difficulty.
Preparatory work
The width of the trench channel prepared for installation of the foundation of the building is 40 cm.
So, you need to pour concrete by installing a strip foundation. All work of the previous stages has been completed: the area has been cleared and marked according to the project. The trench must be prepared for the installation of the foundation of the building. The optimal channel width is about 40 cm. A 15 cm layer of sand is poured and compacted onto the bottom, then a layer of crushed stone is laid. Waterproofing made of roofing felt or plastic film is placed on top of the resulting cake. After this, you can begin constructing the formwork. It is assembled from available materials. It should rise above the ground surface by at least 30 cm. All sewer openings and water pipes must be provided in advance. The reinforcement is laid in two layers in the form of a lattice, fastening the rods with wire. To ensure that the entire structure is inside a concrete monolith, a 5 cm indentation from the formwork walls is provided along the entire perimeter.
You can determine the required amount to fill. To do this, we find the volume of the internal part of the formwork by multiplying its height, width and length. The mortar recipe consists of three parts sand, five parts crushed stone and one part cement. Water is added in parts until the required consistency is obtained. However, it is unlikely that you will be able to prepare the required amount for a one-time filling yourself.
First way
According to SNiP 3.03.01-87 “Load-bearing and enclosing structures”, two laying methods have been developed for monolithic concreting.
The first method, called a “hot seam,” consists of pouring without interruption until the previous layer begins to set, that is, without forming a working “cold” seam.
To do this, you can take a break from pouring concrete for no more than twelve hours. The resulting layer is covered with film or roofing felt at night. Before continuing the pouring, the whitish liquid formed overnight, the so-called concrete milk, is removed from the surface of the previous layer.
Second way
The method of pouring concrete with the formation of a “cold” joint allows you to stop pouring concrete for a longer period.
The second method involves pouring intermittently after the previously laid layer has set, forming a working “cold” seam. Such seams are also called construction seams, working seams and concreting seams. This method allows you to stop pouring for a longer period than one night. But in this case, you should wait until the previous layer has completely hardened. If you pour on a poorly hardened layer, you can get a surface that begins to break, unable to withstand the pressure. The concrete of the joint will become brittle, and the formation of cold bridges that can conduct water will be ensured. Subsequently, such bridges will cause the destruction of the structure’s support. Before pouring the next layer, the surface of the resulting joint is cleared of any dirt or cement film. This will reduce the negative impact of construction joints.
The same SNiP 3.03.01-87 allows not only layers, but also parts. In this case, the working seams will be vertical. To form them, partitions are installed, like formwork.
Fill options
The height of the level of concrete poured into the formwork should not exceed half a meter.
After installing the formwork and calculating the required amount of concrete, you can determine the method of pouring the foundation, as well as the amount of time this work is expected to take. It is more rational to order concrete from a factory and pour the foundation from a machine and not alone. But is there room on the site for machines to operate? Is it possible to order all the necessary equipment within the time frame required to continue the work?
The foundation formwork can be added in layers of about 20 cm. In any case, the height of the level should not exceed half a meter. Each layer is distributed evenly along the entire perimeter of the formwork and along its entire length. To prevent voids from forming, the poured layer is compacted. Tamping is completed when a white liquid appears on the surface of the layer. The walls of the formwork are tapped. These actions are designed to remove air from the concrete and prevent the formation of voids in the monolith. The procedure is carried out until the layer reaches the level of the fixed rope, which indicates the height of the “sole”. After this, the surface is leveled with a trowel. The fittings also make several punctures to release air. The formwork is tapped again.
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. At the same time, 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:
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 improvised 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.
So is it possible to fill your own foundation in parts? You can, if you follow all the conditions and recommendations. This is not advisable, but if there is no other way out, then the stages of work must be carefully followed. In cases where this is not possible, it is better to invite specialists who will carry out such work as quickly as possible.
Pouring a monolithic foundation requires a large amount of concrete, which is not always possible to prepare at one time. Large construction sites are equipped with special equipment and large concrete mixers, but in private construction, it is not always possible to rent or order this equipment. In this case, the question arises: is it allowed to fill the foundation in parts? We will find out the answer to this further.
Concrete for foundation: characteristics and stages of maturation
To make concrete, cement and additional fillers such as gravel, sand or expanded clay are used. Water helps improve the fluidity of the solution, and plasticizers and additives are added to the composition to protect against frost.
After preparing the concrete composition, it is poured into the formwork, followed by maturation:
1. The first stage is setting of the concrete composition. The substance, getting into the formwork, begins to harden; this occurs when cement interacts with water. The bonds between the components are not yet particularly strong, and when loaded on the surface, they are easily destroyed. At the same time, it is impossible to achieve re-setting.
The duration of this stage is determined by the temperature of the external environment and air humidity and ranges from four hours to a day. Reducing the temperature increases the setting time of concrete. At the same time, at the beginning of setting, the consistency of the composition remains liquid. If at this time another solution is added to the composition, then the bonds between them are not broken. At a temperature of 18-19 degrees, the liquid stage lasts about two hours. At a temperature of 0-1 degrees - more than six hours.
It is possible to increase this indicator by mixing the composition, but do not abuse this method, as this negatively affects the performance properties of concrete.
2. The second working stage is the hardening of the concrete composition. This process is quite lengthy and involves gradual hydration of concrete components to give the concrete maximum strength characteristics in relation to the grade of the working mixture. The hardening process on the first day of pouring occurs at an accelerated rate, then the rate of development of this process decreases.
In the first hour after setting, concrete has minimal strength; adding a new portion of the solution will lead to cracking of the surface. Only 3 days after pouring the composition gains the required strength.
Depending on the characteristics of the working cycle of concrete, we can conclude that gradual pouring of the foundation for a house with your own hands is possible, subject to certain recommendations:
- sequential mixing of each portion of concrete, the time between pouring of which does not exceed two hours in warm weather and four in cool weather, no seams are formed, the concrete remains as strong as with continuous pouring;
- during long breaks in work, it is allowed to fill a maximum of 64 hours, no more than after a break, the surface is cleaned of dust and moisture, cleaned with a brush, thus increasing the adhesion between the seams.
When pouring the foundation in parts, do not forget about reinforcement. It is mandatory in any case.
Partial foundation pouring - advantages and disadvantages
The process of periodically pouring the foundation has the following advantages:
1. No need to use heavy special equipment.
Quite often, during construction work, there is no possibility of access to the site with specialized equipment and even a concrete mixer. In this case, the only option is to periodically fill the foundation. Since it is impossible to prepare large quantities of solution without specialized concrete mixers.
2. Increasing comfort during construction work.
It is not always possible to completely fill the foundation; there are reasons when the construction process stops. In this case, gradual pouring of the foundation solves this issue.
Despite this, there are the following disadvantages of pouring the foundation in parts:
- reduction in foundation strength;
- If the work is carried out incorrectly, cracks will appear on the foundation;
- the need to strictly follow the technology.
Complete pouring of the foundation allows you to obtain a monolithic structure with maximum strength characteristics. In any case, the quality of the foundation after partial filling is at a lower level compared to monolithic structures.
Technology of pouring the foundation in parts - calculating setting intervals
Before you start pouring the foundation, read the rules for determining the time and interval for hardening of the concrete composition. Incorrect filling will negatively affect the quality of the foundation.
There are only two stages of concrete hardening:
- grasping;
- hardening.
Each of these processes has individual characteristics and completion times. Immediately after pouring the concrete composition into the formwork, setting begins. The individual components are connected to each other. It is strictly prohibited to touch the concrete solution at this time, in order to avoid compromising its integrity. In warm and hot weather, the concrete solution sets within three hours. In late autumn or early spring, this time increases to 24 hours.
After setting, the structure of the composition remains liquid, therefore, during this process, it is allowed to pour concrete in small portions. However, filling after 24 hours is no longer acceptable.
The next process is hardening. Its duration is about four weeks. After this time, the concrete has completely hardened and is able to bear loads. Three days after the start of hardening, it is allowed to additionally pour concrete onto the already finished coating. In the period from 1 to 3 days after the start of hardening, it is strictly forbidden to pour the solution. Since concrete, without gaining additional strength, cracks under the load of the new composition, although microcracks are not visible, their consequences will appear after the construction of the house. Through these defects, water will enter the foundation, gradually destroying it.
Please note that pouring times in summer and winter are significantly different. So, at high temperatures in summer, the second layer is poured four hours after the main pour; in winter, this time increases to eight hours. When pouring after the mortar has dried, first dry, clean and brush the base.
In addition to determining the time for partial filling, decide on the technology for performing this process. There are two of them:
- block;
- layer by layer
When pouring a strip foundation and constructing an underground trench, the formwork is poured strictly along the soil. In this case, the filling is carried out in compliance with the joints, that is, layer by layer.
When building a strip monolithic foundation, stop at block pouring. That is, the seams are located in a position perpendicular to the joints. When pouring such a foundation layer by layer, it is necessarily reinforced.
Before you start pouring, decide on the method and draw up drawings in the form of a three-dimensional diagram of the foundation. On it, the total area of the foundation is indicated and it is divided into several parts, in relation to the type of fill. In relation to division, we highlight three variants of the scheme:
- vertical division - the base of the foundation is divided into separate parts, separated by steel partitions; after complete hardening, the partitions are removed and concrete is poured;
- oblique pouring is the most difficult method, in this case the territory is divided diagonally, its implementation requires certain experience, it is used in complex structural foundations;
- horizontal partial pouring - the foundation is divided into parts by depth, no partitions are installed between them, it is enough to determine the height of each layer, further pouring is carried out in relation to the scheme and interval of introducing a new portion of concrete.
In addition, on the sketch, indicate the dimensions of the part to be poured, in relation to these indicators, determine the amount of concrete to be poured.
Features of manually pouring the foundation in parts
After drawing up the drawings, proceed to the immediate partial filling. First, build the formwork in the areas where the primary pouring is taking place. Wood, metal or plastic are used to make it. Wooden formwork must have a laminated coating to prevent excessive moisture absorption by the wood.
When using metal structures, choose materials with anti-corrosion coating. Plastic formwork is lightweight and easy to use.
In addition, there are two types of formwork depending on its design:
- national team;
- whole.
- welded;
- anti-corrosion.
There should be two versions of this marking on the foundation reinforcement. Welded reinforcement is durable and prevents cracking of the foundation. Before pouring concrete structures, add sand to the bottom of the structure. Compact it using special equipment. Next, start preparing the concrete solution.
The main ingredients for preparing the solution are:
- sand;
- cement;
- water;
- filler.
The foundation is poured with a high-quality compound of grade 300 or 400. If you have about 85 kg of dry compound, you will need about 42 liters of water. Use only dry sand for work.
It is recommended to pour the foundation in dry and warm weather. When working in the summer, cover the concrete with film to prevent excessive evaporation of moisture. Gradual pouring involves batch preparation of concrete. To calculate the composition for a specific area, first determine its volume. Measure the height, width and depth of the structure, multiply the resulting values and you will get the number of cubic meters of concrete to work with. Prepare concrete in a concrete mixer; this composition is characterized by maximum homogeneity and high quality.
Next comes creating the foundation with your own hands. When pouring the foundation in the form of a strip horizontally, divide the structure into several parts. For example, with a foundation height of 1 meter, it is recommended to perform concreting in three or four layers.
After pouring the concrete, compact the mixture with a vibrator. This device will remove excess air from the structure and improve its adhesion to the reinforcement. In addition, each layer is leveled with a special device or an ordinary wooden plank.
After waiting a certain time, prepare a new portion of the solution and repeat the process. Be sure to compact each layer with a vibrator. If you do not have this device, replace it with regular reinforcement, which is used to pierce the mortar along the foundation. Just keep in mind that this must be done at maximum speed, before the solution begins to harden.
Cover each layer of concrete with plastic film to prevent rapid evaporation of moisture or rain on the surface. If the interval between pouring layers exceeds a day, then before starting to pour the next layer, clean the surface from dust and dirt.
If the gradual pouring of the foundation is carried out on a completely dry base, then pre-treat it with a metal brush to improve roughness and adhesion to concrete.
Pouring a strip foundation is a complex process, but if you approach it responsibly and correctly calculate the hardening time of the solution, the result of the pour will be no worse than that of monolithic structures.
Pouring the foundation video:
An important component of the construction of a building is the construction of a reliable, strong and sound foundation. The basis of the structure is the foundation that carries the load of the entire building and proportionally distributes its pressure on the soil. The strength and durability of the constructed building directly depends on the constructed support, giving it immunity to the appearance of cracks, curvature and warping of walls, window frames and door jambs. For error-free foundation design, it is necessary to take into account the landscape, soil structure, groundwater, and the degree of freezing of the soil layers. But the main stage is pouring, and most novice builders wonder whether it is possible to fill the foundation in parts?
Taking into account time intervals when concreting in parts
To ensure that the quality of the foundation being built does not decrease, it is important to correctly determine the intervals and setting time of the concrete solution. The process of hardening the working mixture includes setting and hardening. The duration of the processes and their parameters depend on the brand of concrete.
The setting of the concrete solution is the initial stage after laying the working mixture. At this stage, it is important not to touch the poured surface, so as not to damage the structure and spoil the quality of adhesion. To combine the individual components of the solution, it will take at least three hours at an ambient temperature of more than 15 degrees Celsius.
The upper setting time interval reaches 24 hours at negative air temperatures. Thus, concrete will set faster at high ambient temperatures. It is worth understanding that the mixture sets only on the top layer; in the middle the solution remains liquid. Pouring in layers for 8 hours allows you to lay a new layer of thin concrete on top.
Hardening of concrete takes about a month. Hardening of concrete occurs after it sets and lasts for a month. After 30 days, the solution finally hardens and is able to withstand various loads. The need for such a long period is due to the use of a thick layer for pouring foundations. The next layer of concrete is poured during the hardening process only on the third day; until this time the poured concrete cannot be touched. Because it is capable of cracking.
Cracks on the surface are not always visible, but they exist, which means they can manifest themselves at the end of the construction of buildings and structures. Thus, laying the working mixture in two layers should take no longer than 8 hours in the cold season, no more than four hours in the autumn and spring, and no more than three hours in the hot season. Laying of subsequent layers should be carried out on a flat, cleaned and dried surface.
Laying concrete in parts requires not only compliance with time intervals, but also pouring methods, of which there are two: block and laying the mortar in layers. With a strip foundation with a filled trench underground, laying the working solution into the formwork should be carried out exclusively on the ground. This method will allow you to pour the mixture evenly end-to-end. With a monolithic strip foundation, block mortar should be laid. In this case, the seams will take a perpendicular position relative to the block joints.
Methods for pouring the foundation in parts
Concrete mortar can be laid in several ways, which depend on the time of the planned pouring. If the concreting process stops for less than 12 hours, then laying the mortar will consist of several parts. Upon completion of laying the part, the finished surface should be covered with roofing felt or film, which will prevent the solution from drying out. Before proceeding with subsequent installation on an already poured surface, you need to remove the concrete mortar from it.
Laying the mortar on the part of the mixture that has not yet hardened is called a “hot joint”. If the interval between laying the mortar exceeds 12 hours, then it is necessary to wait until the previous poured surface has completely hardened. If you neglect this advice, a crust will form on the laid concrete, under which the mixture will not have time to harden. When a new solution is laid on the crust, it will begin to crack under pressure, which will lead to undesirable consequences in the further operation of the foundation.
Layers when pouring the solution can be vertical and horizontal. The latter are laid at ½ half the height of the formwork and do not require delimitation. It is important to take into account the seam when laying the mortar; it should not be in the place where the reinforcing thread is located; it should be laid below or above the steel wire. Vertical pouring requires dividing the formwork using partitions.
Partial filling process technology
To build a strong monolithic structure, concrete should be supplied to the workplace continuously.
The mixer machine will ensure uninterrupted pouring of concrete. This supply will be provided by a mixer machine, which will speed up the concreting process and simplify it. The concrete mixer contains eight cubes of the working mixture; it is delivered to the construction site for further work. However, it is not always possible to carry out concreting in one step. The reasons for this are various: the machine with the concrete mixture is not delivered on time, there is not enough daylight hours, or the mixture is prepared with one’s own hands in a special concrete mixer, which requires time, which means it will not be possible to carry out concreting in one day. Therefore, it is necessary to lay the working mixture in parts.
Before starting concreting, it is important to prepare the formwork; it is installed around the area to be poured. When the formwork is fixed, concrete composition begins to be poured into it. You can prepare a concrete mixture yourself or purchase it at hardware stores. But in the first and second cases it should be diluted with water. Therefore, it is important to monitor the amount of liquid poured, because the brand of concrete will directly depend on it. The solution should resemble sour cream and not be too watery, otherwise it will take a lot of time to harden even at above-zero temperatures.
After the concrete mixture is prepared, you should start pouring it. Pour it into the formwork evenly in one stream. If you pour liquid on different sides, then the foundation will not be level. When the mortar is laid, it should be leveled and compacted. The compaction of the poured surface is carried out with a special tool, with the help of which vibration waves are created. If you don’t have such a tool, you can use a regular wooden plank, but you shouldn’t expect an ideal effect from it. The mixture must be compacted until the air bubbles leave the mixture.
Before proceeding with subsequent concreting, you need to maintain a time period, this applies to the horizontal method. When the area is filled, it must be covered with a special material that will protect the laid surface from precipitation and direct sunlight.
To improve strength, plasticizers are added to concrete. To improve the strength characteristics of concrete mortar, plasticizers can be added to it. Their use eliminates vibration of the poured surface and reduces the pressure from the new part of concrete on the previously laid one. In order for the results from additives to be positive, it is important to observe proportionality when adding them to the mixture.
To ensure that the poured surface is strong, reliable and free of cracks, it is important to adhere to the following recommendations:
- It is important to plan out the steps of the process.
- The area where work is planned should be divided into sectors.
- Taking into account the laying plan of the mixture, distribute its volume that should be supplied to the construction site.
- The working mixture must be laid evenly over the entire surface.
- To maintain the strength of the base and avoid seams, time intervals must be observed.
- When pouring the foundation of buildings in parts, it is important to take into account the recommendations for reinforcement.
