Foundation requirements and treatment methods of flooring construction

2019-03-08
fsgrk
98

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The base surface is the foundation of the floor coating. The strength of the base surface and the adhesion of the floor coating will directly affect the service life of the painted floor. Therefore, the condition of the base surface and its treatment must be paid enough attention.
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The common base materials for floor coating are concrete, cement mortar, terrazzo and corundum floor. The main factors affecting the floor coating are shown in the following aspects.


1.Flatness
The flatness of the base surface refers to the degree of unevenness of the surface of the base surface.
Test Method:
Use 2m to measure the gap under the ruler with a feeler gauge, generally controlled below 3mm.


2. Strength

Insufficient strength of the base surface causes the floor coating to be pulled apart from the base surface, or the base layer is damaged by the force, causing damage to the entire ground. The basic surface compression strength is generally required to be MPa 25MPa.
Test Method:
Use a wire brush or a metal rod to rub the base surface. If sand is used, the strength is not enough. Use a small hammer to hit the base layer. If there is an hollowing, you must take corresponding measures such as grouting.


3. Dryness

The presence of moisture in the concrete and mortar floors reduces the bond strength of the coating to the substrate and also causes bubbling and delamination of the coating.
Test Method:
①The water content of the base surface is measured by a moisture content tester, and the general requirement is to control below 6%.

②Traditional test method: Take a 46cmX46cm plastic film on the concrete surface and seal the four sides with tape paper. After 16h, the water droplets appeared on the film or the surface of the concrete turned black, indicating that the concrete base layer was too wet and not suitable for construction.

②The drying time of the new concrete is generally required to be 28 days or more.


4. Base Attachment

On the surface of the cement base layer, cement dust during construction is generally attached. Especially for the newly constructed concrete surface of the new construction, there will usually be cement slurry (cement free body, loose, no strength), which will affect the floor coating. The adhesion of the layer to the base layer should be removed before construction.


5. Base Defect

(1)Shelling. The cement mortar leveling layer and the concrete joint surface are peeled off, and the adhesion is poor. The simple method of judging is to use a small hammer or metal object to strike the sound of an empty hollowing. If the entire joint surface is peeled off, the mortar leveling layer should be completely removed and the surface should be resurfaced. If only partial peeling is used, it can be repaired by means of a special infusion material perfusion method.

(2) Crack. A "V" shaped groove of about 1 cm width was cut with an electric cutter along the crack portion and repaired with a middle layer material.

(3) Gap. When there are pits or notches on the surface of the base layer, the dust and loose materials are first removed and smoothed with middle layer material.

(4) Poor strength. Due to insufficient cement labeling, unreasonable mortar ratio or poor curing, the strength is poor and the surface is loose. The concrete should be re-cast after removal or strengthened with concrete reinforced base oil.


Source:fsgrk
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