- Ceramic Tile
Ceramic products are varied and depending on their manufacturing processes, they exhibit their own special qualities and properties. The hardness of the ceramic material is directly attributed to its manufacturing process, and generally references the Mohs Scale to categorize its hardness.
The Manufacturing Process
Ceramic tile production begins with the excavation of clays to be used in the manufacturing process. Depending on the type of tile being produced, any number of two to six different types and colors of clay may be necessary to blend together in a mixture.
The selected bulk clays are mixed with water and this mixture is pumped into large, rotating cylindrical mills, where extreme grinding action pulverizes the clay into uniform and homogeneous particles. This substrate is called “body-slip,” and has the consistency of a milk shake.
Next, moisture from the body-slip is evaporated by a spray dryer burner, creating fine particles of uniformly sized dry clay called “powder.” The powder is then fed into molds within a hydraulic press, where it is molded under pressure (approximately 4,000 PSI) to form “green ware” (what the tile is called prior to being fired). The green ware is dried again to further reduce the moisture content, and then travels down “glaze lines” where various types of glazes are applied to the surface.
The glazed green ware travels through a kiln and undergoes a 45-50 minute firing where temperatures can reach 2300°F causing the glaze to fuse to the body. The tile that emerges from this process is very hard, durable and impact resistant.
Hardness of Ceramic Tiles
- Water absorption rate, glazes, compression and material all determine the hardness of ceramic tile
- The percentage of water absorption by the tile body determines whether the ceramic tile is Impervious, Vitreous, Semi-Vitreous, or Non-Vitreous. From Impervious, where absorption rates of 15% and higher, hardness factors change
- Most glazes fall in the 5 to 6 Mohs Scale range. However, certain types of floor and porcelain tiles can have compressive strengths of 10,000 PSI and a Mohs hardness factor of 8
Hot Mix Asphalt (HMA) is a mixture of Asphalt Cement (a petroleum-based “glue” that comprises less than 8%, by weight, the total pavement mixture) and Aggregates (various sized stones, dust, hard inert materials and sand, comprising approximately 92%, by weight, the remaining pavement mixture.)
Asphalt does not cure in the sense that concrete does, and once spread and rolled, it can be cut or drilled almost immediately. Unlike cured concrete, sand in asphalt never bonds as firmly, and the slurry created when sawing will be extremely abrasive. A bond matrix similar to cutting green concrete and undercutting protection steel cores are important factors when undertaking asphalt cutting operations. Some unique factors should be observed when cutting asphalt:
- Hard & large sized Aggregates in the asphalt will cause the blade to cut slower
- The greater the Aggregate-Sand ratio, the faster the blade will cut, but total footage may decrease
- Total asphalt depth can vary. It is common to cut through the asphalt layer into the sub-base. Generally, the sub-base contains a high content of very abrasive materials such as sand, dirt, dusts and like materials. This undesirable situation causes rapid wear of the diamond blade
- Chunks or broken-up asphalt to be cut often attract dirt and sand fillers within the cracks. This, too, will make the asphalt more abrasive and affect the life of the diamond blade