In August this year, four ceramic companies in Jiajiang County were interviewed by the Jiajiang County Market Supervision and Administration Bureau due to the problem of unqualified water absorption of ceramic products and were required to make rectifications within a time limit. In addition, as of September, a total of 16 ceramic companies across the country have been administratively punished for illegal activities of producing substandard products and passing them off as qualified products. Among them, 9 ceramic companies' unqualified products include water absorption.
As one of the indicators specified in the quality sampling inspection of ceramic tiles, the importance of water absorption to the quality of ceramic tiles is beyond doubt. How important is it? In one sentence, it is the basis of the quality of all ceramic tiles. A ceramic production expert once told Zhongtaojun that the quality of ceramic tiles actually depends on the water absorption rate. If the water absorption rate is in place, the quality will generally not be too bad.
01
What is the water absorption rate of ceramic tiles?
During the firing process of ceramic tiles, the raw materials of the green body will produce gas. Most of the gas will be discharged from the green body, but some gas will remain in the green body in the form of bubbles of different sizes and shapes. The ways of existence are: open and closed. There are two types, the opening part has the ability to absorb moisture. The water absorption rate of ceramic tiles refers to the percentage of the weight of the absorbed water to the weight of the product after the opening pores of the product are filled with water.
Water absorption is a key indicator that determines the quality of ceramic tiles. It is the basis of the quality of all ceramic tiles. It affects the hardness, strength, wear resistance and other properties of ceramic tiles to a large extent. Within the standard range, the lower the water absorption rate, the higher the density of the ceramic tile, the better the hardness, strength and other properties of the product, and the higher the inherent stability. Ceramic tiles with low water absorption will not crack or peel due to thermal expansion and contraction due to climate change. If the water absorption rate is higher than the national standard, the ceramic tiles will absorb too much water and may easily appear discoloration, hollowing, falling off, cracking and other quality defects after laying, which may easily lead to consumer disputes.
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But this does not mean that the lower the water absorption rate of all ceramic tiles, the better. Certain products or ceramic tiles used in certain indoor spaces require ceramic tiles with a higher water absorption rate to ensure the paving effect, such as interior wall tiles.
According to the national testing standards for ceramic tiles in my country, ceramic tiles can be divided into:
Porcelain tiles (water absorption rate E≤0.5%);
Stone tiles (water absorption 0.5%≤E≤3%);
Stone brick (water absorption rate 6%≤E≤10%);
Ceramic bricks (water absorption rate is above 10%).
Different ceramic tile products are suitable for different home spaces, and their water absorption standards are also different. Generally speaking, the water absorption standard of interior wall tiles is 3%-12%, which is generally fine stoneware, stoneware bricks or ceramic tiles; the water absorption standard of floor tiles is 0.5%-3%, and most of them are porcelain. Or stoneware.
02
Is the lower the water absorption rate of ceramic tiles, the better?
As more and more consumers pay attention to the water absorption of ceramic tiles, many ceramic manufacturers have gradually reduced the water absorption of ceramic tiles and used low water absorption as a sales point. But is the lower the water absorption rate of ceramic tiles, the better? Zhongtaojun believes that there is no standard answer to this question and requires specific analysis of specific circumstances.
From the perspective of ceramic tile laying, ceramic tiles with too low water absorption will encounter problems with weak adhesion when they are laid on the wall. At present, ceramic tiles still use cement mortar as the main adhesive, and the moisture contained in the cement slurry can be absorbed and solidified by the ceramic tiles, thereby forming the grip of the ceramic tiles on the wall. If the water absorption rate of the wall tiles is too low, this grip cannot be formed, and the chance of the tiles falling off is greatly increased. Therefore, for tiles laid on the wall, it is not good if the water absorption rate is too low.
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From the perspective of ceramic tile quality, the lower the water absorption rate of ceramic tiles, the better the quality. There is no doubt about this. The reason is also mentioned earlier. The lower the water absorption rate of ceramic tiles, the higher their density and the better the hardness, strength and other properties of the product. As for the problem of weak adhesion that may be caused by low water absorption ceramic tiles on the wall, it is due to the use of inappropriate adhesive materials. For laying low water absorption ceramic tiles on the wall, you can use materials such as tile adhesive with better bonding effects..
So many times, you may buy good ceramic tiles (referring to ceramic tiles with low water absorption), but due to inappropriate paving methods and materials, it will also cause a series of problems such as the tiles falling off.
03
How to buy good ceramic tiles with suitable water absorption?
The water absorption rates of ceramic tiles on the market range from high to low. As a consumer, how do you buy ceramic tiles suitable for your home decoration? At this time, the qualification standards for ceramic tile water absorption mentioned above come in handy.
Generally speaking, it is generally not wrong to buy ceramic tiles according to the qualified standards for water absorption of ceramic tiles (floor tiles: 0.5%-3%, interior wall tiles: 3%-12%). When purchasing ceramic tiles, you can ask the merchant to produce a product quality test report to confirm whether the water absorption rate of the product you want to purchase is qualified; or check the relevant instructions on the outer packaging of the ceramic tile to understand the water absorption rate of the product. It should be noted that different spaces and locations have different requirements for the water absorption of ceramic tiles, so when purchasing ceramic tiles, you should consider the actual situation.
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For example, if the bathroom is in a humid state for a long time, water stains are likely to remain. If the water absorption rate of the ceramic tiles is too high, discoloration, mildew spots, hollowing, etc. may easily occur; in the kitchen, wall tiles must be resistant to oil stains and scrubbing because they are infested by oil fumes. , also consider ceramic tiles with low water absorption. Therefore, in spaces such as bathrooms, showers, kitchens, and balconies that have high humidity, are prone to dirt, and require frequent cleaning, it is generally recommended to choose ceramic tiles with relatively low water absorption rates.
If consumers want to measure the water absorption of ceramic tiles by themselves, Zhongtaojun provides two simple test methods here.
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The first method is to drop water on the back of the ceramic tile and observe the diffusion of the water droplets. Bricks that diffuse faster have a greater water absorption rate, and vice versa. This method is relatively simple. It can only roughly understand the water absorption rate of ceramic tiles, but cannot obtain accurate values.
The second method is to record the weight of a ceramic tile before and after it is soaked in water for a period of time, and substitute the two sets of data into the formula for calculating the water absorption rate of the ceramic tile (weight of the tile soaked in water - weight of the tile before soaking in water)/(weight of the tile before soaking in water) The water absorption rate of the ceramic tile can be accurately calculated (the weight of the ceramic tile that has been exposed to water) × 100%.
04
What should we pay attention to when laying ceramic tiles soaked in water?
One of the most important things before laying ceramic tiles is to fully soak them in water. We all know that tiles need to be fully soaked in water before laying them, but many people don’t know why. In fact, soaking ceramic tiles in water before laying has a close relationship with their water absorption rate.
In fact, the purpose of soaking tiles in water is to prevent the tiles from absorbing the moisture in the cement mortar after they are laid, and avoid problems such as hollowing, falling off, and cracks, especially when laying wall tiles. Before the wall tiles are laid, the wall needs to be sprinkled with water, which is the same reason. But whether the ceramic tiles are soaked in water needs to be judged based on the water absorption rate. For ceramic tiles with a water absorption rate below 0.5%, it will not have much impact if they are not soaked in water before paving. However, for ceramic tiles with a water absorption rate greater than 0.5%, it is best to soak them in water before paving. Ceramic tiles with higher water absorption rates require more attention to fully soaking in water.
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When soaking ceramic tiles in water, keep the glaze side up and the ceramic side down. If the glaze is facing down and the corners of the tiles bump into each other, the porcelain will easily fall off. At the same time, it is necessary to pay attention to the fact that the water should not cover the surface of the tiles, so that the tiles can fully "drink water". The tiles should be soaked in water until bubbles no longer appear. Ceramic tiles with high water absorption will take longer to soak. Be careful not to over-soak in water, otherwise it may cause the tiles to turn yellow and discolor.
In addition, considering that laying low water absorption ceramic tiles on the wall may cause problems with weak adhesion, it is recommended to contact theThe paving master must communicate carefully and understand the adhesion strength of the adhesion auxiliary materials in advance to avoid hollowing out of the tiles after they are laid.
(Author: Sitao)
