GB/T 3810.3-2006Test methods of ceramic tiles -- Part 3: Determination of water absorption, apparent porosity, apparent relative density and bulk density (English PDF)

5.1 Drying oven. Operating temperature (110 ± 5) °C; microwave, infrared, or other

drying systems that achieve the same test results may also be used.

5.2 Balance. The weighing precision of the balance is 0.01 % of the mass of the

specimen being tested.

5.3 Deionized water or distilled water.

5.4 Desiccator.

5.5 Microfiber cloth.

5.6 Wire loop, halter, or basket. Capable of suspending specimens in water for weighing.

5.7 Glass beaker, or a container of similar size and shape. The specimen is suspended

from one end of the balance (5.2) using a wire loop (5.6), ensuring the specimen is

completely submerged in water, with neither the specimen nor the wire loop in contact

with any part of the container.

5.8 Vacuum container and vacuum system. A vacuum container of sufficient capacity

to hold the required number of specimens and a vacuum system capable of achieving

(10 ± 5) kPa [(91 ± 5) kPa lower than standard atmospheric pressure 101 kPa] and

maintaining it for 30 min.

6.1 Sampling

Sampling shall be carried out according to the sample area in Table 1.Examples of

sampling of commonly used ceramic tile sizes are shown in Table 2.The number of

whole tiles and the number of specimens depend on the size of the whole tiles. Ceramic

tiles and specimens shall be untested and free from visible damage or cracks. Any loose

or contaminated materials, including mesh, paper, and adhesives used for mosaic tiling,

shall be removed.

If the mass of a single ceramic tile is less than 50 g, a sufficient number of ceramic tiles

shall be taken so that the mass of each specimen reaches 50 g ~ 100 g. For these

specimens, 6.2 does not apply.

The dried specimens are placed in a desiccator (5.4) containing silica gel or other

desiccants, but not acidic desiccants, to cool to room temperature.

Weigh the dried mass (m1) of each specimen, with a measurement accuracy of 0.01 %

of the specimen mass.

7.2 Water saturation

Place the specimens vertically with the cut edge facing down, and the specimens are

not in contact with the vacuum container (5.8). Evacuate to a pressure of (10 ± 5) kPa

[(91 ± 5) kPa lower than standard atmospheric pressure 101 kPa] and maintain it for

(30 ± 2) min. Then, while maintaining the vacuum, slowly inject sufficient water over

a period not exceeding 10 min to cover the specimens and extend it at least 5 cm beyond.

Release the vacuum, submerge the specimens for (15 ± 2) min, and then remove them.

Determine the suspended mass of the specimens according to 7.3.After determining

the suspended mass, remove the specimens. If the suspended mass does not need to be

determined, the specimens can be removed after submerging. Gently wipe each

specimen with a damp microfiber cloth to remove all visible water droplets from the

surface, and determine the saturated mass (m2) of each specimen, with a measurement

accuracy of 0.01 % of the specimen mass. A dry microfiber cloth shall be submerged in

water equal to two times its dry mass (e.g., 100 g of water for 50 g of cloth). This can

be done by placing the microfiber cloth in a bowl, adding the required amount of water,

squeezing the cloth to ensure all of the water is absorbed, and the cloth is saturated with

water, without any dry areas. The surface area of the microfiber cloth shall be at least

7.3 Suspension weighing

After the specimens absorb water under vacuum, weigh the mass (m3) of the specimen

suspended in water, with a measurement accuracy of 0.01 % of the specimen mass.

During weighing, hang the specimen on a wire loop, halter, or basket (5.6) at one end

of the balance (5.2). Before weighing, place the installed wire loop, halter, or basket

immersed in water on the balance and bring the balance to equilibrium. The depth of

the wire loop, halter, or basket in the water is the same as when weighing the specimens.

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