Reinforcement of cast-in-place reinforced concrete slab

In most people's impression, concrete looks hard like a stone, it can withstand the impact of foreign objects and unharmed. However, the fact is not the case. Due to the limitations of raw materials and manufacturing technology, there are a lot of micro cracks and inhomogeneity inside the concrete, and the internal structure is extremely complex. Compared with steel and even wood, it is quite fragile in some aspects. These are all because of the "crisp" of the concrete.

Reinforcement of concrete slabs is usually carried out under the following conditions:

1. Errors in the early stage of design or construction lead to the failure of concrete floor to meet the expected use conditions.

2. The corrosion of steel bars is serious and the bearing capacity of floor slab is insufficient.

3. Cracks occur in the concrete during use, resulting in the reduction of floor bearing capacity.

4. Change the use of construction in the later period and increase the use of load.

There are many kinds of reinforcement methods for the concrete floor defects caused by the above reasons.

First of all, from the reinforcement point of view, can be divided into from the existing floor reinforcement and from the existing floor reinforcement below. From the existing floor reinforcement, mainly for the lack of upper reinforcement is more effective; from the existing floor reinforcement, mainly for the lack of lower reinforcement is more effective. Of course, for specific projects, it is necessary to strengthen the lower part of the lower bending moment bearing capacity, and the strengthening of the upper part can also be strengthened. Even some projects will be strengthened at the upper and lower parts.

Secondly, according to the current industry situation, the reinforcement methods of concrete floor are as follows: the new concrete layer, the reinforcement of the stick steel, the reinforcement of the carbon fiber cloth and the reinforcement of the new beams. The construction specialty of bonded steel and bonded carbon fiber fabric is relatively strong, and the new beam will change the distribution of bending moment of the plate, it is possible to increase the upper steel bar at the same time.

The new concrete layer is reinforced. First of all, if the floor is more cracks around the room, or the lower reinforcement itself is good, only a little lack of reinforcement or insufficient concrete strength, then the basic can be strengthened from the top of the existing floor not less than 40mm of the new concrete layer. Theoretically, the greater the new thickness, the better, but at the same time, the heavier the weight of the new concrete layer, we should consider the existing floor reinforcement and foundation bearing capacity.

The construction methods are as follows:

Repair large cracks;

When necessary, the floor is supported downstairs during the construction period.

Chisel the existing concrete floor, if necessary hit the upper protective layer, clean up the floor;

Lay the upper negative reinforcement and intermediate reinforcement mesh (8 @200), if necessary, the negative reinforcement is long, and the negative reinforcement is implanted into the beam or wall.

Planted connection bars, generally 8 mm in diameter, spacing 600 mm staggered arrangement, if necessary, encryption;

The old concrete interface agent treatment, pouring new concrete (generally new concrete using high-grade shrinkage-free fine stone concrete).