Volakas marble — Technical properties and laboratory tests

The report gives Volakas an apparent density of 2812 kg/m³ and an open porosity of 0.88% (TS EN 1936:2010), water absorption at atmospheric pressure of 0.36% (TS EN 13755:2014) and a water absorption coefficient by capillarity of 0.768 g/m²·s^0.5 (TS EN 1925:2000). Each value is the average of six specimens.

1. Page 3 of the report marks these two values as “not accredited”.
2. The report prints the total porosity of specimen 5 as “331”; the average (3.21) is consistent with a value of 3.31.
3. The report gives the result of this test as four quantities (flow rate, transmission rate, permeability, diffusion resistance factor), so the table shows no single value. Some of the report’s summary values do not agree with the specimen values: the flow rate of specimen 3 against the average and standard deviation, and the standard deviation of the diffusion resistance factor. The values below are as printed in the report.

Volakas has a compressive strength of 146 MPa, the average of ten specimens (TS EN 1926:2013). Flexural strength depends on the method: 5.46 MPa under constant moment (TS EN 13161:2014); under concentrated load, 4.98 MPa with 250 mm between supports and 7.27 MPa with 150 mm (TS EN 12372:2022).

1. The report gives this property in three separate series. Under constant moment the load is applied at two points, under concentrated load at one; the specimens are 300 and 180 mm long. The series are kept apart and not merged into one average.
2. Specimen values are in N and the average in kN; the report gives the standard deviation as “0.23” with the unit (N).

In the pendulum test Volakas has a slip resistance of 56.48 SRV dry and 8.33 SRV wet (TS EN 14231:2004, corrected average). Its abrasion value is 22.23 mm (TS EN 14157:2017) and its Mohs hardness 3.5; polished specimens measured 54.25 Gloss at 60°.

1. Corrected average value. The report gives no slip class or field of use for slip resistance, and it does not state the surface finish of the test specimens.
2. Laboratory note: polished specimens measured 54.25 Gloss, and the slabs were accepted as able to take a polish.
3. Colour scale of the International Commission on Illumination; measured on a slab, as three tests. The report gives the test method as “-”.

In the salt crystallization test the Volakas specimens had an average mass change of −19.16% (TS EN 12370:2020). After 56 frost cycles the compressive strength was 136.3 MPa and the flexural strength 4.52 MPa (TS EN 12371:2011); after thermal shock the average flexural strength was 4.91 MPa (TS EN 14066:2015).

1. Specimen values range from −0.38 to −43.59. The photograph taken after the test, on page 16 of the report, shows pieces broken off some of the specimens.
2. The after-frost values belong to separate groups of specimens; the report gives no rate of change against specimens that were not frozen.
3. Before thermal shock the values are 4.98 MPa, 1776.67 m/s and 0.89%; the first two equal the averages on pages 10 and 12 of the report, while page 3 gives open porosity as 0.88. The report’s rates of change (%) are −1.42, −8.82 and 17.42. The average mass goes from 2156.86 g to 2156.81 g, a change (%) of −0.0023. None of the ten specimens showed oxidation, discoloration, spots, cracks, exfoliation or swelling.
4. None of the six specimens showed oxidation, discoloration, spots, cracks, exfoliation or swelling.
5. Solution A is 150 ml distilled water + 500 ml H₂SO₃, solution B 500 ml distilled water + 150 ml H₂SO₃.

According to the petrographic examination the rock is a dolomitic marble: crystalline in macroscopic texture, granoblastic in microscopic texture, fine and medium in particle size (TS EN 12407:2019). In the XRF analysis the main oxides are CaO (36.6859%) and MgO (16.0924%), with a loss on ignition of 46.6835% (TS EN 15309:2008).

Petrographic examination* (accredited by TÜRKAK)

TS EN 12407:2019, on a thin section. Report pp. 27–28.

Chemical analysis by XRF* (accredited by TÜRKAK)

TS EN 15309:2008. Report p. 21.

Tested between 25.09.2025 and 30.09.2025 at 22.1 °C and 33.0% humidity.

Denomination

TS EN 12440:2017. Report p. 26.

Ohiro, Dolomitic Marble, White, Pale Green

1. The report gives a single distribution value (99) for dolomite and calcite; there are no separate proportions. Figure 1 on page 28 of the report shows dolomite, calcite and quartz.
2. XRF gives the oxide composition, not mineral proportions. LOI: loss on ignition (A.Z., ateş zayiatı, in the Turkish text).

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Tests without an asterisk in the report: roughness (p. 2), water vapour transmission properties (p. 19), colour by spectrophotometer (p. 20), Mohs hardness (p. 24), gloss (p. 25) and denomination (p. 26). On page 3, real density and total porosity are marked “not accredited”.

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