When pouring a monolithic foundation, there is a need for large volumes of concrete, which sometimes exceed several cubic meters. Construction companies approach this issue using heavy equipment such as concrete pumps and mixers. They allow you to mix the solution and feed it into the formwork.
Why layer-by-layer filling
Private developers do not always have the opportunity to use such equipment, because it is quite expensive, and for small plots this approach may be unacceptable due to the lack of access roads for equipment. This problem can be partially solved with the help of a concrete mixer, but the volumes of the mixture, which can be prepared in one load, are limited. In this case, builders are wondering whether it is possible to fill the foundation with parts, because this sometimes affects the strength of the foundation and its operational properties.
Ripening concrete
Concrete is a mixture of fillers and cement that mix with water. To increase fluidity, impart special properties to the mixture and increase frost resistance during kneading, plasticizers and additives can be added to concrete. At this stage, you may wonder whether it is possible to fill the foundation with parts. Pouring a liquid solution into a form called formwork implies the beginning of irreversible processes in concrete, namely:
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 the load acts on the material, then it can break, and the re-setting of the solution does not occur.
What else you need to know about the stages
This phase can vary depending on air temperature and lasts from 3 hours to a day. With decreasing temperature, the setting of concrete takes longer. At the initial stage, it remains liquid, unchanged. If during this period a new portion of concrete is added to the formwork, then the destruction of cement bonds will not occur.
At a temperature of 20 ° C, the liquid stage will last for 2 hours, if the temperature drops to zero, then this period will continue for 8 hours. The time before the start of setting can be extended, for this the concrete is constantly mixed, but its characteristics will be improved, therefore it is not worth abusing the method.
Hardening concrete
If you are faced with the question of whether it is possible to fill the foundation with parts, you should also study the stage of hardening of concrete. This phase will last quite a while, because the components will gain strength over many years. The first 28 days are considered a mandatory period of exposure of the structure to curing. Hardening occurs quickly, which is especially true for the first day, after which the speed slows down.
In the first hours after setting, the concrete will have not so high hardness, and if you add one more portion, this can cause small cracks, because the load on the structure will increase. After three days, these loads do not have a similar effect on the first layers. Given the characteristics of the maturation of the solution, it can be argued that the foundation can be filled in parts, but it is important to follow certain rules.
Recommendations for pouring the foundation in parts
When a private developer asks whether it is possible to fill the foundation with parts, he must first study certain rules for such work. They say: mixing separate lots of concrete in series, it should be limited to two hours or less between pouring, this applies to warm weather. If the 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 the seams are not formed.
If you wondered whether it is possible to fill the foundation with parts, you should remember that long breaks in work should not exceed three days. After a break, the foundation foundation, where it is supposed to be filled with 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 filling the foundation with parts
It is better to fill the foundation continuously, sometimes for this work is not stopped even at night. As a result, it is possible to obtain a monolithic structure, which has a high bearing capacity. But continuous pouring can be achieved only if you use a purchased mortar, which will be fed into the formwork from the concrete mixer tank. If the solution is prepared directly at the construction site, then instead of such a technology, a partial pouring technique is used.
When asking a question about whether it is possible to fill the strip foundation with parts, you should know that, subject to certain conditions, such a structure will not concede in terms of strength to the one that was formed by the method of monolithic casting. The technology of intermittent casting is as follows: at the first stage, it is necessary to form a reinforcing cage, which will consist of horizontal rods. They need to be separated by vertical ties. The distance between the horizontal rods should be selected according to the volume of filling. It usually ranges from 10 to 12 cm.
If you thought about the question of whether it is possible to fill the foundation in parts, useful tips should be read. From them you can learn that at the next stage you can prepare a solution to fill the first layer of concrete. The formwork should be filled evenly, while the thickness of the first layer should be equal to the distance between the horizontal bars, which should be reduced by 1.5 cm. This answers the question of how to fill the foundation with parts with reinforcement. The second layer will flow under the horizontal reinforcement. Once 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 adhered to until you can reach the desired height of the base. The technology is also called layered, and between each individual layers will be fastened with reinforcement. However, if the first layer has already begun to set and has reached the hardening stage, then the second filling can only begin after the first layer has hardened.
Many beginner home masters are wondering if it is possible to fill the foundation in parts, the instructions presented in the article will make it clear. From it you can find out that after pouring the first layer, when it is not supposed to immediately start forming the second, the surface should be wrapped in polyethylene, which will eliminate unwanted evaporation of water. In this case, the second layer can be formed the next day, first you need to remove concrete milk from the surface.
Recommendations for choosing a concrete brand
If you did not have experience in pouring the foundation before, then you need to first think about which brand of concrete you will use. It is recommended that you 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 with parts, what concrete to carry out these works, you must definitely decide.
For difficult conditions, grades M-300 and M-450 are usually used. If the conditions are not so severe, then concrete of the M-100 and M-200 brands can be used. M-100 and M-450 are prepared from the same components, but the recipes are different. For example, M-100 is mixed from:
- 4 parts of sand;
- 1 parts of cement;
- 6 pieces of gravel.
Whereas for the preparation of M-450 should be used:
- one piece of sand;
- one part of cement;
- two parts of gravel.
Conclusion
In order for a cement stone to form, a solution will require 1 part water to 4 parts cement. But when studying the ratio of cement to water, you will realize that most often the proportions look like this: 3 to 2 and 2 to 1.