Water absorption is a parameter that determines the porosity of ceramic tiles. It is measured by the amount of water that ceramic tiles absorb under certain laboratory conditions, and is expressed as a percentage of the dry weight of the tiles.
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According to EN ISO 10545-3, the penetration of water into the open pores of samples is determined using two methods: boiling and water saturation in a vacuum. When boiling, water saturation occurs only in easily filled open pores; with the vacuum method, almost all open pores are filled.
According to EN ISO 10545-3, the penetration of water into the open pores of samples is determined exclusively using the water saturation method in a vacuum. The boiling method, as a test that does not allow determining open porosity and bulk density, is considered obsolete.
The lower the degree of water absorption, the more resistant the tile will be to intense mechanical and hydrothermal influences.
A low water absorption coefficient indicates that the structure of the tile is porous, and a high coefficient indicates that the structure of the material is more dense.
According to the EN 14411 standard, ceramic tiles and slabs are divided into three main groups based on water absorption. Where the third group corresponds to the lowest water absorption rates.
Material on this issue is presented in the article Water absorption .
Frost resistance - the ability of ceramic tiles to withstand freezing in a humid environment and at temperatures below 0 degrees Celsius. The freezing mechanism is divided into two stages. The first stage is the penetration of water from the environment into the pores of the tile. The second stage is the hardening (freezing) of water inside the pores. As is known, the transition of water from a liquid to a solid state is accompanied by an increase in volume, since the density of ice is less than the density of water. Thus, when water freezes inside the pores, the tile is subjected to mechanical stress, which can lead to cracks or chipping of part of the material.
According to EN ISO 10545-12:1997, tests confirming frost resistance properties are carried out as follows: ceramic tiles or slabs, after being saturated with water, are subjected to alternate temperatures of +5 ° C and minus 5 ° C. They are then completely frozen for at least 100 freeze-thaw cycles. After 100 freeze/thaw cycles, the faces and edges of ceramic tiles or slabs are examined for damage.
The frost resistance property of ceramic tiles is not guaranteed in extremely low temperature zones (below -40 °C). This is due to the test conditions of EN ISO 10545-12:1997, as they are carried out at temperatures between +5°C and -5°C. In this regard, manufacturers mark materials suitable for use in such an environment with a special EXTRA°C sign, which in turn indicates testing in the temperature range from -50 °C to +100 °C.
Based on the mechanisms described above, the frost resistance of a material is determined by the possibility of water penetration into the material, in other words, the degree of water absorption. Thus, if a material does not absorb water, it is frost-resistant, but if it does, it is not.
Based on the mechanisms described above, the frost resistance of a material is determined by two parameters: 1) The presence and number of pores that allow water to penetrate into the material; 2) The shape and size of the pores, the volume of voids of which, allows you to distribute the loads of the changing state of water. It follows from this that frost resistance is directly related to water absorption: the lower the water absorption, the greater the likelihood that the material is frost-resistant. However, there are also highly porous materials (with a high rate of water absorption) that are characterized by frost resistance. Frost resistance in this case is due to the shape and size of the pores, allowing moisture to penetrate into the material without destroying it as a result of hydrothermal loads.
According to EN ISO 10545-12:1997, tests confirming frost resistance properties are not carried out as such. A material is considered frost-resistant if it falls into group 1 of materials according to the degree of water absorption (<3%).
Frost resistance also prevents ice from forming on the face of the tile. This is due to the fact that water, without getting inside the material through the pores of the top layer, seems to “roll off” from the surface.
Material on this issue is presented in the article Frost resistance .
Abrasion resistance is a mechanical characteristic of a lined surface. Indicates the surface’s resistance to wear due to exposure to rubbing objects, surfaces, and materials. Which expressions do you think are correct?
The wear resistance requirements for unglazed ceramic tiles and slabs are set by EN 14411 and depend on water absorption and the method of their manufacture.
Abrasion resistance also affects other functional characteristics of the ceramic tile surface, such as chemical and stain resistance and ease of maintenance. Naturally, this aspect is equally important for glazed and unglazed tiles, because... abrasion leads to a weakening of the tile structure itself, the appearance of pores and microcracks invisible to the naked eye, into which dirt, etc. gets clogged.
Abrasion resistance is a property characteristic only of glazed ceramic tiles. Since intense and prolonged exposure to the surface over time can lead to partial loss of the glazed layer, and this, in turn, will lead to exposure of the ceramic mass and, as a consequence, to the loss of not only the aesthetic, but also the functional qualities of the facing surface. Damage to unglazed tiles is almost invisible, since abrasion of the top layer leads to exposure of the ceramic mass, which in unglazed tiles is no different from the top layer.
According to the test method EN ISO 10545-7:1998, glazed tiles are divided into wear resistance classes, from "0" to "5". Where fifth class tiles are least resistant to abrasion.
The important point is that unlike other quality tests on tiles, durability testing does not determine the value of the tile. The results of the study divide the tiles into classes, each of which corresponds to a specific purpose of the tile, and in no way to divide the tiles into “bad” and “good”.
Information on this issue is presented in the article Abrasion resistance, wear resistance .
Thermal resistance is the ability of ceramic tiles to withstand without damage the stress caused by dimensional deformations due to sudden changes in temperature, especially if such changes are repeated frequently. Which statements do you think are correct?
If we compare the thermal resistance testing methods of the EN ISO 10545-9 standard and GOST 27180-2001, we can conclude that the test requirements of the EN ISO 10545-9 standard are somewhat stricter than the requirements of GOST 27180-2001.
The test method described in GOST 27180-2001 is as follows: samples are subjected to 10 rapid cycles of temperature changes from 15 °C to 145 °C. The maximum temperature is achieved by placing the samples in an oven for at least 20 minutes, the minimum by completely immersing them in water at a temperature of 15°C. At the end of 10 cycles, samples are inspected for visible defects.
Thermal resistance is the ability of a material to resist the transfer of energy (heat exchange) from more heated parts of the body to less heated bodies, carried out by chaotically moving body particles (atoms, molecules, electrons, etc.).
Thermal resistance is an important physical property of ceramic tiles. Let's imagine, for example, the tiled surface of a kitchen countertop on which a hot pan is placed. The surface of the tile heats up sharply and, as a result, expands, and the lower layers become colder and less expanded as they move away from it. In this state of thermal inhomogeneity, the tile, which does not have the property of heat resistance, could be deformed and, being an inherently rigid material, could crack.
“Resistance to thermal shock” is a property characteristic only of refractory materials, the scope of which is the metallurgical, glass, chemical industries, as well as all other industries where work takes place using blast furnaces, shaft and rotary furnaces.
Material on this issue is presented in the article Thermal resistance .
Slip resistance is determined by the kinetic and dynamic conditions of motion of the body interacting with the surface. When it comes to flooring, it is obvious how the degree of slip is related to the safety of using the surface. Knowledge of surface properties is essential for the cladding designer, tiler, retailer and end user, as well as the safety inspector. Please mark the correct conclusions in your opinion:
Ceramic tiles, characterized by their smoothness and shine, form the most intimate contact between the surface and the sole, thereby increasing the coefficient of friction. While rough, uneven surfaces tend to allow water or other liquids to accumulate on them, as well as dirt, grease and other substances that act as lubricants. In addition, the area of contact with the sole, in this case, is limited by the protruding edges of the surface, which also reduces slip resistance. This factor must be taken into account when choosing tiles.
Friction coefficient is a parameter characterizing the degree of surface sliding. It is proportional to the force parallel to the interaction surface that must be applied in order to create relative motion between two bodies. The higher its characteristics such as smoothness and shine, the lower the coefficient of friction for floor surfaces, since this contributes to the appearance of a thin, continuous layer of water (as well as grease, dirt, etc.), which acts as a lubricant between the sole and the floor. Ceramic tiles, while smooth and shiny, create a slippery surface and increase the risk of falls and accidents.
According to the DIN 51097 method, in rooms where floors are often wet and where people walk on them barefoot (for example, swimming pool sides, children's pools, common shower rooms, saunas, etc.), the classification contains groups: A; B (A+B); C (A+B+C). Where A is the slipperiest tile.
The DIN 51130 and DIN 51097 methods, also called "incline plane methods", consist of a person walking back and forth on a platform covered with the tiles being tested. The inclination of the test section increases at a constant rate until an angle is reached at which the person begins to feel unsure when walking, that is, begins to slide.
According to the DIN 51130 method, floors in production facilities or work areas where there is a high risk of slipping are classified into the following groups (according to the average inclination angle): NC; R9; R10; R11; R12; R13. Where R13 is the slipperiest tile.
Material on this issue is presented in the article Slip resistance on dry and wet surfaces .
