Today, there are a lot of people who build houses without projects, and from this there is a need to complete the construction of various rooms, and, accordingly, foundations. All sorts of extensions are made to existing houses: rooms, porches, and those who live on the ground floors of old apartment buildings (in Khrushchevs) attach balconies. Some people remember about fireplaces, but catch up too late, so the foundation for a brick fireplace turns out to be a free-standing structure inside the house.
But what to do so that the new foundation does not move away from the old one over time and a crack opens between the two structures?
The answer is simple: both foundations are linked into a single structure.
To connect both foundations, it is important to anchor correctly, and not in the way most builders do when hammering rebar into concrete. A clogged reinforcement calms only the owner himself that it is there, but does not protect the structure from deformations at all.
In fact, the tensile force in the foundations is so strong that it even breaks concrete and tears the reinforcement, and you say "hammer"?
With this approach, one end of the reinforcement is in concrete, and the other end is simply in the hole, from which the bar can be easily removed when pulled out. In this case, the reinforcement works only for shear and not for tension.
The steel rod has ribs, which must be in the concrete without voids, and only in this case a reliable coupling of the rod and the hardened concrete mixture is ensured.
Correct anchoring
Correct anchoring involves gluing the reinforcing bar into the concrete, and this approach eliminates the effect of slipping of the bar inside the structure.
It is done like this:
1. A hole is drilled in a concrete structure with a depth of 25-30 reinforcement diameters and a thickness of 2.5-3 reinforcement diameters (for example: when using an anchor based on a 10 mm rod, the hole depth will be 30 cm, and its diameter will be 25 mm)
2. The hole is thoroughly blown out of dust and spilled with water for good adhesion of already hardened concrete and only hardening mixture. The hole treated in this way ensures good adhesion.
3. The hole is filled with anchoring mixture. There are 4 options:
a) As a mixture, a ready-made anchorage mixture with a hardening time of 5-15 minutes is used, for example, Ceresit CX15 or GLIMSPRO ANCHOR (not advertising). A 25 kg bag costs from 1000 to 1500 rubles.
b) A mixture based on self-expanding alumina cement in a ratio of 1: 4 to sand. Hardening is achieved in 20-25 minutes. This solution is non-shrinking. Cement ГЦ-40 50 kg costs ~ 2500 rubles, but enough for two hundred anchors.
v) A common cement-sand mixture (cement M-500) in a ratio of 1: 3 with the addition of PVA glue (hardening for 1-2 days). The disadvantage of such a mixture is that it slightly decreases in volume (shrinks).
G) Using a chemical anchor. Here it is allowed to reduce the diameter of the hole, but the method itself is expensive due to the cost of the chemical tanker.
To make 3-4 anchors, you need to spend on average 1000 rubles. Very expensive!
Many people still use tile adhesive for street mounting, but I cannot advise it, since I have never used it ...
4. The rod is placed in the hole, squeezing out excess mixture. Then, we give time for the anchoring mixture to harden.
This describes the correct approach to anchoring, which guarantees reliable adhesion of structures under various loads acting on the structure.