The SL-Deck is produced on traditional casting beds of typically 80-150-meter length and up to 3.6-meter width in a 24-hour production cycle that involves the following steps:
1) Laying out mortar (optional)
A thin layer of mortar is automatically placed by a machine before the light-weight concrete is casted. The process ensures that the bottom surface of the slab will be smooth and appear similar throughout the production. This option is used when the raw concrete is painted and used as visible ceiling in the final construction.
If a ceiling with acoustic or architectural properties is needed in a project, the mortar can be left out and the light-weight concrete will be showing. Depending on the type of ceiling used, the exposed porous light-weight concrete will have a positive sound dampening effect in the room below. This solution is often used for schools, offices, museums and similar structures.
2) Automatic casting of light-aggregate concrete
The light-aggregate concrete is casted automatically using the LAC machine developed to create the special geometry needed in the SL-Deck. The machine is capable of casting up to 3 meters per minute and thus complete a 100-meter casting bed in app. 30 minutes. The light-weight concrete is casted as long continuous plates with raised portions of concrete forming the lengthwise and transversal grooves.
The machine is controlled by a computer using an input file generated by the production planning software for each day of production. The input file is used to determine where light-weight concrete should be casted and where it should be left out for openings, slab ends or zones of strong concrete such as is needed for slab incorporated reinforced beams. The operator can follow the casting process on an integrated control panel.
3) Placing reinforcement
After the light-weight concrete has been casted, the slab is reinforced with pre-stressed lengthwise and non-stressed steel crosswise using a machine capable of pulling the wire and placing the crosswise reinforcement. During this process any fittings, steel plates for welding or other details are also placed in their correct position.
4) Casting of self-compacting concrete
The hydraulic sides of the casting bed are pushed in place and the closed form is filled with the self-compacting concrete. Lifting anchors are placed directly in the semi hardened concrete.
After 12 hours, when the self-compacting concrete has achieved sufficient strength, the sides are removed and the tension is removed from the pre-stressing cables. The slabs are cut by saw and each slab is ready to be lifted out of the casting bed and transported to the factory storage yard.