words, stone people often encounter such a situation:
customer: "Hey! Why is there a crack in your stone? Are you deliberately fooling us with defective products?"
Stone dealer: "No, dear, the physical properties of the natural stone you choose are prone to cracks, but our installation will not affect the use!"
some users reflect
found that there was a "crack" after buying stone"
thinks he's been cheated.
However, it is normal for natural stone to have cracks.
this is because natural stone is composed of different minerals
it's very difficult to achieve a precise arrangement in their natural state.
that the surface may crack
this also shows that cracks and cracks are not the same
cracks will not affect the use of stone
and cracks will affect the use
first, we should explicitly measureStonephysical traits of commonly used indicators:
1. Bulk density
the ratio of mass to volume of stone. High density indicates that the rock has a high proportion and capacity, and has a high stability in the process of sawing, grinding, throwing and cutting.
2, water absorption
refers to the water absorption capacity of the stone, which reflects 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 good weatherability and frost resistance, and the frost resistance test is not required.
3, flexural strength
refers to the ability of a certain gauge of facing board to resist fracture at two support points. The flexural strength of the tested stone is about 1/14 to 1/8 of the compressive strength. The flexural strength of the stone can be roughly inferred from the compressive strength. The greater the flexural strength, the more difficult the plate is to break.
4. Compressive strength
refers to the ability of rock to resist failure under unidirectional compression. The magnitude of the compressive strength indicates the hardness of the rock. The compressive strength is expressed in MPa, 1MPa = 10.2kg/cm².
So, what kind of natural stone is up to the standard?
Qualified marble should achieve physical performance indicators:
Bulk density ≥ 2.6 g/cm & sup3;
water absorption ≤ 0.5%
compressive strength ≥ 50MPa (according to the standard of "JC 79-92 natural marble building board", the compressive strength of marble is not less than 20MPa; the compressive strength of marble is generally between 70 ~ 110MPa)
flexural strength ≥ 7MPa
Qualified Granite shall meet the physical performance index:
Bulk density ≥ 2.56 g/cm & sup3;
water absorption ≤ 0.6%
dry compression strength (compressive strength) ≥ 100MPa (according to the standard of "JC 205-92 natural granite building board", the compressive strength is not less than 60MPa; Granite compressive strength is generally between 110 ~ 245MPa)
bending strength (flexural strength) ≥ 8MPa (according to the standard of "JC 205-92 natural granite building board", the flexural strength is not less than 8MPa)
because natural stone is naturally occurring
has its own physical characteristics
and the resulting differentiation
has been nurtured by nature for hundreds of millions of years.
will undoubtedly have some flaws, such as miscellaneous lines, spots, etc.
marble is not an industrial product
its impurities, colors have absorbed the essence of nature
different geography, environment and level of marble will produce different spots and color difference
so,
the stone has cracks is not defective, will not affect the use
should look at it with a normal mindset.
micro letter to read this article:stone defective with cracks?
