In other words, stone people often encounter such situations:
Customer: "Hey! How come your stone is cracked? Are you deliberately fooling us with inferior products?"
Stone dealer: "No, dear. The physical characteristics of the natural stone you choose are easy to crack, but our installation will not affect the use!"
Some users reported that
"Cracks" appear unexpectedly after purchasing stones
Thought he was cheated
However, it is normal for natural stone to have cracks
This is because natural stone is composed of different minerals
They are difficult to achieve precise arrangement in natural state
So that cracks may appear on the surface
It also shows that cracks are different from cracks
Cracks will not affect the use of stone
The cracks will affect the use
First of all, we should define the common indicators for measuring the physical characteristics of stone:
1. Bulk density
The ratio of stone mass to volume. High density means that the rock has a large specific gravity and volume, and it has a high stability in sawing, grinding, throwing, cutting and other processing processes.
2. Water absorption
Water absorption refers to the water absorption capacity of the stone, reflecting the number, size, distribution and connectivity of the pores contained in the stone. The water absorption rate of rock is generally less than 1.5%. If it is less than 0.5%, it can be regarded as having good weather resistance and frost resistance, so the frost resistance test can be omitted.
3. Flexural strength
It refers to the ability of facing plate of a certain specification to resist fracture at two supporting points. The flexural strength of stone is about 1/14~1/8 of the compressive strength. The flexural strength of stone can be roughly inferred from the compressive strength. The greater the bending strength, the less likely the plate is to break.
4. Compressive strength
It refers to the anti failure ability of rock under unidirectional compression. The compressive strength indicates the hardness of the rock. Compressive strength is expressed in MPa, 1MPa=10.2kg/cm ²。
So, what kind of natural stone is up to standard?
Physical performance indexes of qualified marble:
Volume density ≥ 2.6g/cm ³
Water absorption ≤ 0.5%
Compressive strength ≥ 50MPa (according to the standard of "JC 79-92 Natural Marble Building Plate", the compressive strength of marble is not less than 20MPa; the compressive strength of marble is generally between 70 and 110MPa)
Bending strength ≥ 7MPa
Physical performance indexes of qualified granite:
Volume density ≥ 2.56g/cm ³
Water absorption ≤ 0.6%
Dry compressive strength (compressive strength) ≥ 100MPa (according to the standard of "JC 205-92 Natural Granite Building Plate", the compressive strength is not less than 60MPa; the compressive strength of granite is generally between 110 and 245MPa)
Bending strength (bending strength) ≥ 8MPa (according to the standard of "JC 205-92 natural granite building board", the bending strength is not less than 8MPa)
Because natural stone is naturally generated
It has its own physical characteristics
And the resulting differentiation features
It was nurtured by nature through hundreds of millions of years
Undoubtedly, there will be some defects, such as mixed lines, spots, etc
Marble is not an industrial product
Its impurities and colors have absorbed the essence of nature
Marbles with different geographical locations, environments and layers will produce different spots and color differences
So
Cracks in stone are not inferior products, which will not affect the use
We should look at it in a normal way
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