What test results does a terrazzo supplier hand you?
Reference photographs. They show the material and the finish; they are not photographs of goods we made, and the colour on screen is not a colour-match.
The figures, and where each one comes from
| Grade | Water absorption | Flexural strength, average | Minimum single value |
|---|---|---|---|
| Standard terrazzo | not more than 8.0% | not less than 5.0 MPa | not less than 4.0 MPa |
| High-performance terrazzo | not more than 6.0% | not less than 8.0 MPa | not less than 6.5 MPa |
| Cement artificial stone | not more than 4.0% | not less than 10.0 MPa | not less than 8.0 MPa |
| High-performance cement artificial stone | not more than 1.0% | not less than 15.0 MPa | not less than 12.0 MPa |
Why the processes are not interchangeable
Three reasons a number moves. First, the standard reports the WORST specimen: JC/T 507-2022 clause 7.5.3 takes the single highest absorption result in the group, while many laboratories report the average. One bad tile in ten and the two numbers diverge. Second, the two systems test different properties under different names: ASTM C880 measures flexural strength by quarter-point loading on dimension stone, and the specimen and span are not the same as the 150 by 100 millimetre specimen at a 100 millimetre span used in JC/T 507. Third, and most often skipped, the tests are not equivalents. A report to ASTM and a report to JC/T are two separate test programmes, and neither laboratory is wrong. What is wrong is reading one number as if the other standard required it.
What these figures are, and what they are not
The four grades and their figures are from JC/T 507-2022 table 7. The reporting differences described are from clauses 7.5.2 and 7.5.3 of the same standard and from the published scopes of ASTM C880/C880M-18 and ASTM C97/C97M-18, which cover dimension stone. ⛔ We have not tested any panel we have supplied and we do not publish test results of our own. Ask us for what we hold, and we will say so.
If you are specifying this
We have not published products against this question yet. Send us the process, thickness and quantity and we will quote it against what we can actually form, rather than against a catalogue.