|Production Guide - Fibre or Micro Concrete Tiles (SKAT, 1992, 67 p.)|
|3. Production process|
After tiles have been cured for 24 hours in a horizontal position, they are carefully moved to the curing tank where they are kept completely under water in a vertical position for at least 5 days, provided the water temperature is above 20°C.
Mark the date on the curing tank to avoid confusion. (See also Production Management Guide)
After demolding, the tiles must immediately be moved to the curing tank. Never allow the tiles to dry in the sun or wind before water curing.
The water level in the curing tank should be checked daily. The tiles should be covered by at least 20 mm.
Curing at Low Temperature
If the water temperature is below 20°C, the curing time must be increased.
For a temperature of 15°C, the curing time must be at least
For a temperature of 10°C, the curing time must be at least 11 days.
Make sure that the water temperature is measured because it is lower than the average daytime air temperature.
Curing Time for Tiles Cast with a high Water to Cement Ratio
If the water to cement ratio is higher than 0.5, the curing time must be increased as well.
Change of Water
If the water becomes too aggressive on the skin, it should be changed, this may be once a week, but at least every two months. At the same time the tank should be cleaned.
Curing in clean water is especially important when producing colored tiles. Old water may cause white stains.
There are different possibilities for storing the tiles in the tank:
Stacking the tiles in a row
Stacking the tiles in sets of three tiles.
Stacking in sets is a space and time saving method, but is only possible with tiles that have a nib at the top. It involves a certain risk of damage to the nibs.
Another method is to cure the tiles above water in air saturated with water vapor.
This can be achieved by placing only a little water in the curing tank. The tiles are stored above the water level. The tank is then made airtight by covering it with a black plastic sheet. As the tank is exposed to the sun, the enclosed air becomes saturated with humidity and the temperature rises, thus accelerating the setting process.
The water level must be checked at least every morning.
This environment, where the curing temperature is higher, favors the curing process. The result is a strong product with a smooth and clean surface.
The method is especially advantageous for colored tiles, giving a proper coloring without white stains.
Properly mark the daily batches with the date of production and product number so that the curing time can be checked.
(See also Production Management Guide)