Abrasion resistance, wear 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. A variety of objects can intentionally or unintentionally come into contact with and affect the cladding. If we are talking about the floor surface, then these are shoe soles, cart wheels, etc., furniture, chairs and other loads that are often dragged along the floor. At the same time, the surface is exposed to water, dirt, snow, sand, organic matter, etc. Even cleaning and routine care of the tiled surface (using a broom, mop, rags, powder cleaning agents, etc.) is already a source of abrasion due to friction of relatively solid substances against the surface of the tile. As a rule, this leads to the following consequences:

1. The top layer of the tile is abraded;
2. Changes in the surface itself, loss of shine, change in color, etc.

Although these effects are related, they do not always occur simultaneously, especially when it comes to glazed tiles. In any case, when using glazed tiles, it is logical to assume that intense and prolonged exposure to the surface will eventually lead to partial loss of the glazed layer, and, consequently, exposure of the ceramic mass, as well as to a significant loss of not only aesthetic, but and functional qualities of the facing surface.

Damage to unglazed tiles is less noticeable. Abrasion of the top layer leads to exposure of the ceramic mass, which in unglazed tiles is no different from the top layer. A method for testing the abrasion resistance of glazed tiles is given in the EN ISO 10545-7:1998 , IDT standard. The assessment of the degree of abrasion of the tile is determined by visual observation, based on the results of friction against the surface of the tile of a special abrasive material, the test involves the use of an instrument specifically designed for this study (laboratory abrasion circle). Based on the results of these observations, glazed tiles are divided into the following wear resistance classes (in accordance with CEC/EUF recommendations):

1. Class 0 . Glazed ceramic tiles and slabs of this class are not recommended for floor coverings;
2. Class 1 . For non-abrasive indoor floors using soft-soled or bare footwear (e.g. residential bathrooms and bedrooms without direct access from the outside);
3. Class 2 . For floor coverings in rooms with a minimum amount of abrasive contaminants, using soft or ordinary shoes (for example, living areas in houses, excluding kitchens, hallways and similar areas with frequent walking). This does not apply to special shoes, such as stiletto heels;
4. Class 3 . For floor coverings in rooms with a small amount of abrasive contaminants, with the use of ordinary shoes and with frequent walking (for example, kitchens, hallways, corridors, balconies, loggias and terraces). This does not apply to special shoes, such as stiletto heels;
5. Class 4 . For floor coverings of premises with a certain amount of abrasive contaminants, with regular walking, with loads greater than for class 3 (for example, industrial kitchens, hotels, exhibition and retail premises);
6. Class 5 . For floor coverings in areas with a certain amount of abrasive contaminants, with intense foot traffic over long periods of time, as a result of which the glazed ceramic tiles and slabs used are subject to extreme stress (for example, public areas such as shopping centers, airport lobbies, hotel lobbies, public pedestrian paths and industrial areas).

In this regard, it must be emphasized that, unlike other quality tests of tiles, this study does not determine the value of the tiles; the results of the study divide the tiles into classes, each of which corresponds to a specific purpose of the tile. In this case, the requirements depend on the terms agreed between the manufacturer-seller and the buyer-consumer. That is why abrasion resistance is the most suitable criterion for selecting tiles, depending on their purpose.

Methods for testing the abrasion resistance of unglazed tiles are given in EN ISO 10545-6:1997 , IDT. Abrasion occurs as a result of friction against the surface of a ceramic tile by a rotating disk with a special abrasive material, and is expressed by the volume of material removed from the surface of the tile. The results of this test have more to do with the technical characteristics of the tiles than with the aesthetic effects of wear.

There is another aspect that is not always given due attention (even in the summary of standards). We are talking about the effect of abrasion on other functional characteristics of the surface, such as, for example, resistance to chemical attack and staining, 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.  

CEC - Federation Europeene des Fabricants de Carreaux Ceramiques.
EUF - Europaische Union der Fliesenfachverbande.