Travertine used for outer wall

- Mar 14, 2021-

Travertine is composed mainly of calcium carbonate.The environment in which caverns form is mainly the ocean floor, at least at the bottom of large lakes.Commercially valuable cavestone mines require uniform material with beautiful grain.Only at the bottom of the ocean or the bottom of a large lake, where hydrodynamic conditions are very weak, can hot springs from underground flow smoothly around, and the calcium carbonate in them can settle evenly and form beautiful lines.One of the major defects of commercial caverns is the curved lines, which are the result of disturbances when hot springs are gushing out.

The mainstream color of the hole stone is light beige, and yellow hole stone, coffee hole stone, super white hole stone, red hole stone, gray hole stone.Cave stone makes people feel mild, rich in texture, prompting the decoration of buildings often have a strong cultural and historical flavor, so it is favored by architects;

 Travertine is characterized by low strength, loose texture, easy water in the hole, frost and thaw resistance and weather resistance are poor.Some of the very low strength cave stone, processed stone even in the process of transportation fracture, broken.In view of this, taking into account the safety function of the curtain wall, the cave stone curtain wall should also have a certain scope of application and a certain use restriction.

1, Travertine should not be used in schools, kindergartens, nurseries, hospitals, the elderly living on the outside of the building wall.

2, Travertine should not be used in shopping malls, railway stations, airports, exhibition halls, grand theater, office buildings and other personnel mobility of the building wall.

3, Travertine should not be used in the T-junction is opposite the road wall.

4, Travertine should not be used in high-rise and super high-rise building wall.

5. Travertine should not be used in heavily polluted, acid rain environment areas and Marine environment areas.

6, Travertine should not be used in cold areas, cold areas and large annual temperature change areas.

7, when the Travertine is used on the outer wall, the single area of the Travertine should be less than the area of granite;And the long and short sides should be determined according to the texture of the cave stone.

8. The weakness of the edge strength of the Travertine should be considered in the connection form between the Travertine and the steel skeleton.

9, Travertine water absorption rate should be lower than granite.

10. When the Travertine is used on the outer wall, the bending strength of each batch of Travertine should be checked. The unqualified ones are strictly prohibited to be used.

11. When the Travertine is used on the outer wall, there should be certain strengthening measures to ensure the safety of the cave stone curtain wall.

12. When the Travertine is used on the outer wall of the super high-rise building, experts should be organized to carry out feasibility demonstration. It can be adopted when the demonstration is feasible, and reliable safety measures should be taken.

Test requirements for cavitation application

Due to the great difference in the quality of cave stone from different producing areas, basic material quality tests should be carried out before determining the ore veins for the market.

13.5. Bending test

When ore veins are determined, stone specimens are selected to carry out drying and saturation bending tests. Drying and bending tests are the basic indexes of material properties.The saturated bending strength is helpful to understand the sensitivity of stone to water.Clean stone specimens should not be attached with reinforcement layer and composite layer.

13.6. Water absorption rate

Without surface waterproof treatment of stone and waterproof treatment of stone should be tested, after waterproof treatment of stone, water absorption rate should not be greater than 1%.

13.7. Freeze-thaw coefficient

Freeze-thaw coefficient refers to the ratio of the bending strength after a certain number of freeze-thaw cycles to the bending strength without freeze-thaw cycles.It determines whether the stone can be used in cold areas.This test should be carried out in areas where negative temperatures are likely to occur.

Only after the basic material property test is carried out and these basic conditions are confirmed, the tunneling can be processed as a panel and used in curtain wall engineering.

13.8. Thickness of plate

The flexural test shows that the flexural strength of the thick panel stone is lower than that of the thin one.But because the bearing capacity of the plate is proportional to the square of the thickness, the bearing capacity of the thick stone is larger than that of the thin stone.

The minimum thickness of the cavern stone plate can be determined by the standard bending strength value FK:

When FK ≥8.0MPa, the minimum thickness is 35mm.

When 4.0≤ FK < 8.0MPa, the minimum thickness is 40mm.

The standard value of bending strength, Fk, is its test mean minus 1.645 times standard deviation.When this value is less than the test minimum value, the test minimum value shall be adopted.

The allowable deviation of plate thickness is +2mm, -0mm, and no negative deviation is allowed.

13.9. Dimensions of plates

Cave stone strength is low, so the size of the plate should not be too large, generally should be controlled within 1.0㎡.

It is not suitable to use slender strip stone, this kind of SLATE is easy to break in the process of transportation and installation.Of stone material become than had better be in 1:2 within, unfavorable exceed 1:3.

13.10. Surface treatment

Cave stone water absorption is very high, waterproof coating should be used to reduce its water absorption rate to less than 1%.

The stone curtain wall with the glue injection plate seam, the stone stone can only do the outer surface of the large surface waterproof;When the open plate is used, the stone should be waterproof on six sides.

The hole is large, the hole number is too much hole stone, should carry on the sealing treatment.

Waterproof treatment should be carried out after all the slots and holes are machined, cleaned and dried.