The traditional double-layer terrazzo tile is made up of two layers, indipendently prepared, which become a single body during the moudling operation in the press.
The sight face of the tile is the first layer, so called because it is the first to be introduced in the mould of the press. It is made of marble or granite granulates, marble powder, white or grey cement, mixed with water.
The dry second layer works as absorbent of the water in excess from the wet first layer and as a “support” of the same. It is made of sand, crushed stone powder and grey cement.
The double-layer terrazzo tiles are produced in a 6 or 7-station revolving hydraulic press where the moulding process is sequentially carried out in stages. Then the fresh moulded tiles undergo the curing process, at the end of which they are strong enaugh for the subsequent operations of calibration, polishing, chamfering. The curing can be “natural”, that permanence of 2-3 days in a covered area at room temperature or “accelerated”, that is 1 day in closed chambers with programmed addition of steam to raise temperature and humidity.