Tiles are a type of thin unit that comes in square or rectangular shapes, and can be made from a variety of materials such as natural stone, ceramic, baked clay, glass, metal, terrazzo, and quartz. The selection of tiles for flooring purposes is based on various factors such as their strength, aesthetics, cost, and other such characteristics.
One of the essential requirements that tiles need to satisfy is their transverse strength. This refers to the amount of weight a tile can support and is represented numerically. In order to estimate the breaking load of a tile, transverse strength tests are conducted in a laboratory setting. These tests include both wet and dry testing methods. The strength of a tile determines the type of application it is suitable for, making it an important factor to consider in the selection of tiles for flooring purposes.
Apparatus
The tile testing machine is comprised of an angle iron frame with a double lever system for applying load. The lower lever is supported on a ball bearing and contains a counterbalanced weight and a receiving pan. Lead shots are supplied into the pan and can be transferred to a storage pan by removing a pin. The storage pan is permanently fixed to the top plate.
The upper lever is connected to the lower lever with straps and can be adjusted with an adjustable capstan. A loading yoke is connected to the upper lever through vertical rods passing through the top plate. The loading yoke cross head can be locked in place after mounting the specimen. Three self-aligning bearing rollers, with a diameter of 40mm, are provided on metal blocks. Guide pins are fixed to the block and corresponding holes are drilled on the top plate to adjust the center distance of bearing rollers to 250mm and 270mm for 320mm and 345mm long tiles, respectively.
The third rolling roller, also with a diameter of 40mm, is attached to the loading yoke and can be adjusted to sit centrally on the specimen while loading. The load is applied to the specimen by allowing the lead shots to flow into the receiving pan through a supply pipe with a valve. The valve’s orifice is adjusted to load the specimen at a rate of 45-55 Kg/min.
An L-shaped plate is attached to the lower lever and will automatically strike the valve’s shutter as soon as the specimen fails, cutting the flow of lead shots. Twelve times the weight of lead shot collected in the receiving pan gives the failure load. The counterbalancing weight slides on the screw of the lower lever and can be locked in position with two nuts after balancing the lever. A stop is provided to restrict the movement of the lower lever when the specimen fails.
Tile Specimen
To ensure the quality of the tiles, it is necessary to conduct tests on their dry strength and wet strength. The testing process will involve six tiles for dry strength and another six tiles for wet strength. By testing a sufficient number of tiles, it will be possible to obtain accurate and reliable results regarding the strength of the tiles.
Testing for dry strength is important because it determines the amount of weight a tile can bear without cracking or breaking when it is dry. On the other hand, testing for wet strength is crucial because it indicates how well a tile can withstand moisture and other wet conditions. By conducting tests on both dry and wet strength, it will be possible to assess the overall durability and resilience of the tiles in different conditions.
Therefore, it is important to adhere to the specified testing requirements and ensure that the appropriate number of tiles are tested for both dry and wet strength. This will provide valuable information about the quality and strength of the tiles, which can be used to make informed decisions about their use in various applications.
Machine Operation
To begin with, attach the counter balance weight to the screw located on the lower lever. Proceed to adjust the loading roller and the yoke according to the thickness of the specimen. It is crucial to ensure that the counter weight is appropriately adjusted so that the lower lever is in a balanced position.
Once the specimen is securely placed on the loading rollers, the lead shots can be introduced into the system. This can be achieved by operating the shutter lever, which can be done by pressing it down. During this process, it is important to keep a close eye on the lower lever as it will strike the shutter with significant force when the specimen fails. This impact will cause the shutter to close, stopping the flow of lead shots.
Dry Test Procedure
To conduct a tile specimen test, the first step is to place the air-dried tile horizontally on bearers. It is important to ensure that the wearing surface of the tile is facing upwards and that its sides are parallel to the bearers. To provide additional support, a 3mm thick and 25mm wide plywood packing should be placed between the tile and the bearers, as well as between the tile and the loading bar.
The load should be applied to the mid-span of the tile specimen, starting from zero and increasing steadily and uniformly. It is important to ensure that the rate of increase does not exceed 200kg per meter width, which is measured along the bearer, per minute. The load should be increased until the specimen fails, and the breaking load should be noted.
To ensure accurate results, the experiment should be repeated on the remaining tile specimens. The breaking load of each specimen should be recorded, and the average breaking load should be calculated. By following these steps, researchers can accurately determine the strength of the tile specimens being tested.
Wet Test Procedure
To conduct a test on tile specimens, it is recommended to immerse them in water for a duration of 24 hours. This step allows the tile to absorb water and simulate its behavior under wet conditions. Once the 24-hour period has elapsed, the specimen should be carefully removed from the water and wiped dry to eliminate any excess moisture.
After the specimen has been dried, it is ready for testing using the dry test method. This test involves evaluating the specimen’s properties and characteristics in a dry state. By comparing the results of the wet test and the dry test, it is possible to gain insights into how the tile will perform under different conditions and to identify any potential issues or weaknesses. Overall, the combination of the wet and dry tests provides a comprehensive assessment of the tile’s suitability for its intended use.
Results
The given context describes a scenario where breaking load due to dry test and breaking load due to wet test are recorded, and the transverse strength can be computed using a specific equation. However, there is no further information provided about the specific context in which this scenario occurs.
In general, the breaking load of a material refers to the amount of force that is required to break or rupture the material under certain conditions. In this case, two different tests have been conducted: one under dry conditions and one under wet conditions. It is not clear what type of material is being tested or what the specific conditions of the tests are.
The concept of transverse strength refers to the ability of a material to resist forces that are applied perpendicular to the material’s surface. This type of strength is important in a variety of applications, such as in the construction of bridges, buildings, and other structures.
The equation that is mentioned in the context is not provided, so it is not possible to discuss the specifics of how the transverse strength is calculated. However, it is likely that the equation takes into account the breaking load measurements that were recorded during the dry and wet tests, along with other factors that may be relevant to the material being tested.
Overall, the given context provides a brief description of a scenario involving breaking load tests and the calculation of transverse strength. However, without additional information, it is difficult to fully understand the context and the significance of the results that were obtained.
Where:
P: breaking load, N
I: span between supports, mm, see Table 1.
b: tile width, mm
t: tile thickness, mm
Table 1 designated span for tiles to be tested for transfer strength
| Size of tile, mm | Span, mm |
| 200×200 | 150 |
| 250×250 | 200 |
| 300×300 | 250 |
| 400×400 | 300 |