Good afternoon, dear guests and subscribers of the "Build for myself" channel!
Lack of concrete during the construction of a structure is an infrequent occurrence, but unfortunately it does occur!
With the aim of economic benefits, many land owners decide to build a house on their own and starting such work without experience, there is a very high probability of making a mistake somewhere. It is experience that makes you reconsider your mistakes, but just - without it, it is almost impossible to take into account all the nuances.
Many novice self-builders do not take into account the formwork errors, and what is even sadder, due to insufficient fastening - the formwork can break anywhere and a cube or two of concrete is already overboard.
Undoubtedly, such situations arise among experienced builders, because, in addition to inattention, force majeure cases arise: the mixer driver decided to deceive and not deliver the mixture or the concrete mixer broke down on the way, as well as an accident at the plant for the production of commercial concrete.
Lack of concrete
Of course, the ideal design is one piece continuous concreting, but partial casting can be very close in quality if a number of conditions are met.
In fact, if there is not enough concrete mix, then we need to fill the structure in two or even more stages. The situation in which there was not enough concrete refers to partial concreting, which in turn is subdivided into horizontal joint (layered) and vertical joint (block).
Important! In case of partial concreting - do not make an oblique seam!
Block concreting
So, block concreting is concreting by sections (blocks) with a vertical "cold" seam. With this method of laying individual blocks, it is imperative to wait for the mixture to harden by at least 30% of the brand strength, which under normal weather conditions at + 25 ° C is 3-5 days.
When it turns out that there is not enough concrete to fill the grillage or monolithic tape and there is nowhere to take it, then a section of the foundation is allocated and limited on both sides by shields with sawn holes for the rods fittings. This section is equal in volume to the volume of the missing mixture and will be concreted later using the "cold seam" technology, i.e. must be filled no earlier than 3 days later.
Layer concreting
The second option is layered concreting. When a shortage of concrete is detected, we accelerate the laid concrete along the entire belt and leave a space of the same height around the entire perimeter of the house. It is important here that the thickness of this layer should not be less than 10 cm and the seam should not be located along the longitudinal reinforcement.
Of course, you need to evaluate all the nuances locally. If we were not delivered 1 cubic meter, then it makes no sense to disperse concrete across the entire belt, we will not get the required layer thickness of 10 cm. and expose the upper belt of the reinforcing cage. Then the builders use the following option:
For example: 3 walls of the house are poured completely to the top of the formwork, and the fourth wall of the foundation is fenced off on both sides with vertical shields, then a layer for future pouring with a thickness of 10-15 cm remains. - this is the best option.
Layer concreting also means hot seam concreting if the interval between coats is less than 12 hours.
A prerequisite for this event is the care of each layer, namely, each poured layer is covered with a film and is not allowed concreting later than 12 hours, and if such a delay occurs, then we postpone the work for 3 days and resort to work using the "cold seam ".
Important!
Shabai or beginners - make a number of mistakes and lay a new layer before the full grasp of the previous one occurs. It is possible to pour a new portion of concrete when the previous layer has not yet hardened (less than 12 hours), or when it has exceeded the stage of initial hardening and gained strength 30% of the brand one (more than 72 hours).
In the case of a hot seam, before pouring, the cement film formed from the cement laitance over the entire contact area of the layers must be cleaned off with a metal brush.
It's important to have a side track
Before constructing a structure, in order to prevent situations with a shortage of concrete, you need to objectively assess a number of factors:
- an alternative to a concrete manufacturer (is there a place where you can quickly buy some concrete, because not all of them release small volumes);
- evaluate your strength or labor force in the case of manual mixing;
- availability of retail outlets where several bags of cement can be picked up quickly.
Unfortunately, we will see a shortage of concrete only after the fact, when the last mixer truck finished its delivery.
According to experience, most often there is not enough concrete volume - up to 2 cubic meters, so I advise you to always have a dozen bags of cement, a pile of rubble and sand on a construction site. These are the materials that are always in demand and even if they are not needed now, they are used in the construction process.
Also, it is better to order an extra cube before pouring, then the headache will be less! And if the concrete remains, you can knock down the forms for curbs or lintels over the windows in advance, then the extra concrete will be very useful for you!
Thank you for attention!
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