Causes and preventive measures of hollow stone floor

01. The concept of stone hollow

After the marble slab is laid, there is a gap between the slab and the bonding layer, or the bonding layer and the base layer are not tightly bonded, we call it empty drum.

Empty drums will cause the loose corners of the stone to produce a "breathing" effect, reducing the bearing capacity of the stone on the ground. The settlement and tearing of the foundation part of the ground can also cause the ground stone to crack.

02. Detection method of stone hollow

● Percussion method: when testing, tap the stone with a hollow hammer to make a thumping sound, which is an empty drum.

● Coring method: drill the core and observe the hollowing condition.

03. Analysis of the reasons for stone hollowing

1. Temperature

When the temperature is lower than 5 degrees during construction, the cement mortar does not have a complete hardening reaction, resulting in the cement mortar not reaching its due strength;

2. Back treatment

The floating ash on the back of the stone is not cleaned, or the water is not wet enough, which affects the bonding;

3. There is no effective protection on the bottom surface of the stone

The stone protection has been in the alkaline environment of the cement mortar layer and the geothermal heating environment for a long time to gradually form thermal melting, mildew, degumming, separation and peeling, which makes the stone and the bottom mortar separate, resulting in the deformation and cracking of the hollow drum;

4. Materials and proportions

The sand in the cement sand is too fine or the mud content is too much, or the cement parameter is too small;

5. Basic treatment

The dust and oil stains on the base layer are not cleaned up, resulting in the weak bonding layer, or the bonding layer is too thin and not thick enough;

The base layer is too dry, the grout is not brushed in place when the ground is swept, or it has been dried before the stone is laid, resulting in insufficient adhesion between the mortar and the plain cement grout bonding layer, forming an empty drum;

The thickness of the finished surface of the stone is too large from the base layer of the floor, and it is easy to sink and hollow after pasting

6. Construction technology

Combined with the layer of mortar is not compacted, stone shop paste is not hit solid;

7. Maintenance

Maintenance period did not end, people walk on the car, resulting in loose ground empty drum.

8. Environmental and seasonal reasons

Due to seasonal changes, the stone paving in the cement mortar has not been completely dry, if the temperature drops suddenly, it will cause the water in the mortar can not be completely dry.

When the temperature rises, due to the reasons of thermal expansion and contraction, there will be a hole between the stone and the base, then loose, fall off, the formation of empty drum.

04. Preventive measures of empty drum

1, before paving stone, understand the structure of the ground, observe whether the structure is rigid body, cushion with cushion is empty drum, cracking. When laying stone materials on the building expansion joint and settlement joint, we must choose the corresponding approach in accordance with the atlas. The construction must be disconnected from the construction, and it is not simple to remember that the map can not be laid directly.

2, in the stone paving before, to check the board, found dark cracks, sandwicked and other hidden quality stone to remove;

3, in the construction of large area of ground stone, it is best to leave 1~2mm natural seam between plate and plate, do not completely close seam paving, to prevent the future due to temperature difference, water pressure in the stone caused by stone drum cracking.

4, in the stone shop paste, to choose rubber hammer to hit the stone, the percussion strength is moderate, should be light, scattered percussion. During the use of stone ground, due to the pressure of excess load, will also lead to ground cracking, should be prohibited, the project in the completion phase of the use of instructions, should be emphasized.

5, maintenance: after the ground stone paving paste, the maintenance time is best not less than 7 days, during the maintenance period to ensure that the ground is wet, between this is not allowed to people, if you need people should lay the covering for the corresponding finished product protection.